Unveiling the role of the PI3K/Akt signaling pathway in follicular development and non-malignant ovarian dysfunction: a comprehensive review

Abstract

Phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) is an important signaling pathway that regulates cell survival, metabolism, and proliferation, with pivotal roles in key stages of follicular development, including primordial follicle activation, granulosa cell function, and oocyte maturation. Dysregulation of this pathway is closely related to follicular development disorders and decreased female fertility. This review synthesizes current knowledge on the regulatory mechanisms of the PI3K/Akt pathway in ovarian physiology and its dysregulation in non-malignant ovarian dysfunctions. It further examines how environmental pollutants disrupt this pathway to impair ovarian function and evaluates preclinical evidence for therapeutic interventions targeting this axis in models of polycystic ovary syndrome and premature ovarian insufficiency, including pharmacological agents, Traditional Chinese Medicine, and innovative techniques like ovarian tissue activation. While these findings highlight the pathway’s pivotal role and therapeutic potential, most evidence remains preclinical. Future translation to clinical practice requires addressing interspecies differences, advancing human studies, ensuring the safety of follicle-activating strategies, and developing targeted delivery systems to ultimately improve outcomes in female reproductive health.

Introduction

Follicular development is a complex and highly regulated biological process, involving the precise regulation of multiple signaling pathways. Among these, the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway is one of the core pathways regulating follicular development. Akt plays an important regulatory role in follicle survival and activation, granulosa cell proliferation and differentiation, as well as the meiotic maturation of oocytes [1, 2]. Abnormal activation or inhibition of the PI3K/Akt signaling pathway is closely related to various severe non-malignant ovarian dysfunctions in women. In premature ovarian insufficiency (POI), this pathway may induce either excessive activation or inhibition of follicles, both of which can result in premature follicular depletion or inadequate function [3, 4]. Similarly, in patients with polycystic ovary syndrome (PCOS), abnormal activation of the PI3K/Akt signaling pathway correlates with granulosa cell proliferation disorders and hormonal secretion irregularities [5–7]. Additionally, abnormalities in the PI3K/Akt signaling pathway during follicular development can lead to developmental disorders of follicles, affecting female fertility [8–10]. This review aims to comprehensively explore the regulatory mechanisms of the PI3K/Akt signaling pathway in follicular development, synthesizing current knowledge and highlighting the implications of these pathways in non-malignant ovarian diseases. By elucidating these molecular mechanisms, this review not only seeks to deepen our understanding of follicular biology but also identifies potential therapeutic targets for clinical intervention in non-malignant ovarian dysfunction such as POI and PCOS. The insights gained from this review will contribute to advancing treatment strategies and improving the reproductive health of women affected by these conditions.

Literature search strategy

For this narrative review, we searched PubMed and the CNKI (China National Knowledge Infrastructure) database for literature published between 2009 and 2025. The search combined keywords and, where applicable, MeSH (Medical Subject Headings) terms related to ‘PI3K’, ‘Akt’, ‘follicle’, ‘granulosa cell’, ‘oocyte’, ‘polycystic ovary syndrome (PCOS)’, and ‘premature ovarian insufficiency (POI)’. Inclusion criteria were: (1) studies on the PI3K/Akt pathway in follicular development or non-malignant ovarian dysfunction; (2) studies on environmental/chemical modulators of this pathway in the ovary; (3) therapeutic studies targeting this pathway; (4) peer-reviewed original research, clinical reports, or reviews in English or Chinese. Exclusion criteria were: (1) non-peer-reviewed publications; (2) studies for which the full text was unavailable; (3) duplicate publications; and (4) non-original research (e.g., editorials, letters). After screening titles, abstracts, and full texts against these criteria, 94 articles were selected for inclusion in this synthesis.

The PI3K/Akt pathway in follicular development

The PI3K/Akt signaling pathway is a central regulator of ovarian follicular development. Gene expression and activity of this pathway are dynamically regulated across different follicular stages [11], enabling it to orchestrate a series of critical, stage-specific events. These include the initial activation of primordial follicles, the subsequent proliferation and steroidogenic function of granulosa cells, and the final growth and meiotic maturation of the oocyte [10, 12–14]. This section details the context-specific roles and regulatory mechanisms of the PI3K/Akt pathway in each of these key physiological processes (Fig. 1), highlighting its indispensable function in female reproduction. A summary of the cell-type-specific roles of the PI3K/Akt pathway in these key ovarian compartments is provided in Table 1.

Fig. 1.

Schematic diagram showing the regulation of follicular development by the PI3K/Akt signaling pathway. The PI3K/Akt pathway may influence follicular development by regulating granulosa cell apoptosis, oocyte maturation, hormone secretion from granulosa cells, and oxidative stress. Furthermore, this pathway is regulated by environmental pollutants, non-malignant ovarian diseases, and therapeutic agents. GAB2: GRB2-associated binding protein 2; IRS: insulin receptor substrate; SH: src homology; PI3K: phosphatidylinositol 3-kinase; PIP2: phosphatidylinositol 4,5-bisphosphate; PIP3: phosphatidylinositol 3,4,5-trisphosphate; PTEN: phosphatase and tensin homolog; PDK1: phosphoinositide-dependent kinase 1; Akt: protein kinase B; TSC1: tuberous sclerosis complex 1; TSC2: tuberous sclerosis complex 2; NFE2L2: Nuclear factor erythroid 2-related factor 2; FOXO3: forkhead box O3; FZR1: fizzy and cell division cycle 20-related protein 1; mTORC: mammalian target of rapamycin complex; mTOR: mammalian target of rapamycin; APC: anaphase-promoting complex; MPF: maturation-promoting factor; eIF4E: eukaryotic initiation factor 4E; S6K: ribosomal protein S6 kinase; rpS6: ribosomal protein S6; NF-κB: nuclear factor kappa B; SOD: superoxide dismutase; GSH-Px: glutathione peroxidase; HO-1: heme oxygenase 1; NQO1: NAD(P)H dehydrogenase [quinone] 1; GCLC: glutamate-cysteine ligase, catalytic subunit; FasL: fas ligand; BimEL: bcl-2 interacting mediator of cell death, el isoform; Bax: bcl-2-associated X protein; Bcl-2: B-cell lymphoma 2; CDK1: cyclin-dependent kinase 1; CDK2: cyclin-dependent kinase 2; ROS: reactive oxygen species

Table 1.

Role of the PI3K/Akt pathway in key ovarian follicular compartments

Cellular Compartment	Key Upstream Signals / Regulators	Major Downstream Effects & Outcomes	Representative References
Primordial Follicle / Oocyte (Activation)	IGF-1, Insulin, EGF, PDGF, CDC42, PTEN (inhibitor)	1. Activation: Akt-mediated FOXO3 phosphorylation and nuclear export release the brake on follicle quiescence. 2. Growth & Synthesis: Akt inhibits TSC1/2, activating mTORC1. This promotes rpS6 phosphorylation (protein synthesis) and Cyclin D1 expression, driving initial follicle growth.	[15–24]
Granulosa Cells	FSH, GH (via JAK/STAT), BMP4/BMP7, Kallistatin, FGF21 (via FGFR1/β-Klotho), IL-4 (context-dependent)	1. Survival/Anti-apoptosis: Akt phosphorylates FOXO3, inhibiting pro-apoptotic BimEL; also inhibits Caspase-9. 2. Proliferation: Promotes CDK2/Cyclin D1 activity. 3. Steroidogenesis: Activates mTOR, upregulating StAR, CYP11A1, and CYP19A1 to enhance estrogen synthesis. 4. Antioxidant Defense: Activates NFE2L2 (Nrf2), upregulating SOD, GSH-Px, HO-1.	[25–36]
Oocyte (Growth & Meiotic Resumption)	IGF-1, LPA, PDK1	1. Maturation & Anti-apoptosis: Regulates CDK1/Cyclin B (MPF) activity; inhibits Bax/Caspase-9, promotes Bcl-2. 2. Translation & Growth: mTORC1 activates rpS6 and eIF4E for protein synthesis. 3. Meiotic Progression: Akt phosphorylates FZR1, activating APC to degrade Cyclin B and inactivate MPF, enabling the metaphase I to anaphase I transition.	[37–42]

This table summarizes the primary, cell-type-specific inputs and outputs of the PI3K/Akt pathway. For comprehensive details on cross-talk and context-dependent regulation, please refer to the main text (Sect. 2.2, 2.3, 2.4).

PTEN is a key negative regulator (phosphatase) of the pathway, included here among upstream regulators for its critical inhibitory role

IL-4 can exhibit context-dependent effects, promoting apoptosis in certain POI settings as described in the text

Abbreviations: APC Anaphase-Promoting Complex, BMP Bone Morphogenetic Protein, CDK Cyclin-Dependent Kinase, CYP11A1 Cytochrome P450 Family 11 Subfamily A Member 1, CYP19A1 Cytochrome P450 Family 19 Subfamily A Member 1 (Aromatase), EGF Epidermal Growth Factor, eIF4E Eukaryotic Initiation Factor 4E, FGF21 Fibroblast Growth Factor 21, FGFR1 Fibroblast Growth Factor Receptor 1, FOXO3 Forkhead Box O3, FSH Follicle-Stimulating Hormone, GH Growth Hormone, GSH-Px Glutathione Peroxidase, HO-1 Heme Oxygenase 1, IGF-1 Insulin-like Growth Factor 1, IL-4 Interleukin-4, JAK/STAT Janus Kinase/Signal Transducer and Activator of Transcription, LPA Lysophosphatidic Acid, MPF Maturation-Promoting Factor (CDK1/Cyclin B complex), mTORC1 Mechanistic Target of Rapamycin Complex 1, NFE2L2 (Nrf2) Nuclear Factor Erythroid 2–Related Factor 2, PDGF Platelet-Derived Growth Factor, PDK1 3-Phosphoinositide-Dependent Protein Kinase 1, rpS6 Ribosomal Protein S6, SOD Superoxide Dismutase, StAR Steroidogenic Acute Regulatory Protein, TSC1/2 Tuberous Sclerosis Complex 1/2

Basic pathway components

The canonical PI3K/Akt pathway comprises several key components. PI3K is activated by upstream signals such as receptor tyrosine kinases or G protein-coupled receptors, leading to the phosphorylation of PIP2 (phosphatidylinositol 4,5-bisphosphate) and the generation of the critical second messenger PIP3 (phosphatidylinositol 3,4,5-trisphosphate) at the plasma membrane [43]. PIP3 then recruits both Akt and its activating kinase, PDK1 (3-phosphoinositide-dependent protein kinase 1), resulting in the phosphorylation of Akt at Thr308 and Ser473 and its full activation [12, 44–47]. A major negative regulator of this pathway is the lipid phosphatase PTEN, which antagonizes PI3K signaling by catalyzing the dephosphorylation of PIP3 back to PIP2, thereby attenuating the signal [48, 49].

Activated Akt subsequently phosphorylates a network of downstream effector molecules that are central to ovarian function. Among the most critical are the forkhead box O (FOXO) family transcription factors (e.g., FOXO3). Akt-mediated phosphorylation of FOXO proteins promotes their nuclear export and functional inactivation, which relieves FOXO-dependent repression of genes involved in cell cycle progression and apoptosis [50–53]. Another pivotal downstream node is the mammalian target of rapamycin complex 1 (mTORC1). Akt activates mTORC1 by phosphorylating and inhibiting the TSC1/TSC2 (tuberous sclerosis complex 1/2). Once activated, mTORC1 drives protein synthesis, cellular growth, and proliferation, largely through phosphorylation of ribosomal protein S6 (rpS6) and modulation of the translational machinery [18, 19, 54]. Beyond these core effectors, Akt also phosphorylates a wide array of other substrates involved in metabolism, cell survival, and transcriptional regulation, allowing it to coordinate diverse biological outputs [55].

Primordial follicle activation

The transition of primordial follicles from a quiescent to a growing state is tightly controlled by PI3K/Akt signaling within the oocyte. Key upstream activators in this context include insulin, insulin-like growth factor 1 (IGF-1), and CDC42 (cell division cycle 42) [15, 22]. As detailed in Sect.  2.1 and Fig. 1, activation of this pathway leads to Akt-mediated phosphorylation and nuclear exclusion of FOXO3, releasing its brake on follicle activation [16, 17, 23]. Simultaneously, Akt activates mTORC1, driving cyclin D1 expression and rpS6-mediated protein synthesis, which are essential for initiating oocyte growth [18–21, 23]. Notably, pharmacological manipulation of this pathway (e.g., with PI3K activators or PTEN inhibitors) can promote activation in both mouse and human ovarian tissue models [56], highlighting its pivotal role. However, its dysregulation (e.g., excessive PI3K activity) can cause premature follicle depletion, contributing to POI [57].

The Hippo signaling pathway is another key regulator of follicle activation [58]. Yes-associated protein (YAP) and its paralog transcriptional coactivator with PDZ-binding motif (TAZ) are the core co-activators and effectors of the Hippo pathway [59]. YAP/TAZ activity is negatively regulated by the Hippo kinase cascade. Importantly, cross-talk exists between the PI3K/Akt and Hippo pathways. PI3K can positively regulate YAP/TAZ activity [60], promoting their interaction with TEA domain family members to drive transcriptional programs essential for follicle activation. Conversely, YAP/TAZ can also influence AKT phosphorylation, indicating that the Hippo pathway reciprocally modulates PI3K/Akt signaling [61]. Thus, during primordial follicle activation, the PI3K/Akt and Hippo pathways engage in coordinated cross-talk, jointly serving as a critical switch that releases follicles from their dormant state.

Granulosa cell proliferation and hormone secretion

Granulosa cells are indispensable for follicular development, providing metabolic support to oocytes and, after ovulation, differentiating into progesterone-secreting luteal cells. Dysfunction of granulosa cells can lead to ovulation disorders and luteal phase deficiency [62]. The PI3K/Akt pathway integrates a multitude of extracellular signals to precisely regulate granulosa cell proliferation, survival, apoptosis, and endocrine function.

Proliferation and survival signals

Follicle-stimulating hormone (FSH) is a master regulator that activates PI3K/Akt signaling in granulosa cells. A key downstream mechanism involves the Akt-mediated phosphorylation and nuclear export of the transcription factor FOXO3 (as detailed in Sect.  2.1). This relieves FOXO3-mediated repression of cyclin D, driving cell cycle progression, while concurrently inhibiting the expression of the pro-apoptotic gene BimEL (bcl-2 interacting mediator of cell death, el isoform) to promote survival [25, 26].

The proliferative response is further refined through extensive cross-talk with the MAPK (mitogen-activated protein kinase)/ERK (extracellular signal-regulated kinase) pathway, which is also activated by FSH [63]. FSH upregulates the expression of Ras, a shared upstream node that concurrently activates both PI3K/Akt and MAPK signaling to promote proliferation [24, 64]. A key point of intersection is Raf1: Akt phosphorylates Raf1 at Ser259 to inhibit its activity [55, 65], while Raf1 itself activates ERK1/2 [66]. Thus, the activation status of ERK1/2 is modulated by a balance between activating inputs (e.g., phosphorylation at Ser338) and this inhibitory input from Akt [67, 68]. This multi-layered, dynamic molecular dialogue between the PI3K/Akt and MAPK pathways underscores their synergistic role in driving granulosa cell proliferation.

Integration of metabolic and stress signals

Growth hormone activates PI3K/Akt via the JAK/STAT (Janus kinase/signal transducer and activator of transcription) pathway, enhancing the expression of antioxidant enzymes like SOD (superoxide dismutase) and GSH-Px (glutathione peroxidase) to protect granulosa cells from oxidative stress [27, 28]. It is critical to recognize that reactive oxygen species (ROS) play a dual role. At physiological levels, ROS are essential signaling molecules required for normal folliculogenesis and ovulation [69–71]. The PI3K/Akt pathway helps maintain this delicate balance, as exemplified by the role of growth hormone in mitigating excessive ROS and apoptosis in PCOS granulosa cells [29]. However, pathological ROS accumulation, as seen in PCOS, disrupts this balance and impairs fertility [29, 72, 73].

Other vital regulators utilizing the PI3K/Akt axis include members of the TGF-β superfamily (e.g., bone morphogenetic protein 4/7) and kallistatin, which promote survival and proliferation [30–32]. Conversely, negative regulators such as ubiquitin-specific peptidase 25 (which stabilizes PTEN) and the adaptor protein LNK can suppress pathway activity and cell growth [74, 75]. The outcome is highly context-dependent, as illustrated by IL-4, which activates PI3K/Akt in POI settings to paradoxically induce granulosa cell apoptosis [34].

Regulation of steroidogenesis

The PI3K/Akt/mTOR axis is a crucial modulator of estrogen biosynthesis. It upregulates the expression of key steroidogenic enzymes, including StAR (steroidogenic acute regulatory protein), CYP11A1 (cytochrome P450 family 11 subfamily A member 1), and CYP19A1 (cytochrome P450 family 19 subfamily A member 1) [35]. This regulation is mediated by factors such as fibroblast growth factor 21 and endoplasmic reticulum oxidoreductase 1 alpha, which activate the pathway to enhance estrogen production [35, 76]. Furthermore, the circadian regulator Bmal1 (brain and muscle ARNT-like protein 1) influences granulosa cell steroidogenesis by affecting the expression and phosphorylation levels of PI3K, Akt, and mTOR [25, 77, 78].

Oocyte growth and meiotic resumption

During oocyte growth, PI3K/Akt signaling is stimulated by factors like IGF-1 and lysophosphatidic acid [37, 38]. This pathway is essential for cytoplasmic maturation, as its inhibition suppresses the expression of key maturation-related genes (e.g., bone morphogenetic protein 15, growth differentiation factor 9) and reduces the rate of polar body extrusion, while promoting pro-apoptotic signals [79]. Conversely, pathway activation enhances maturation [80]. Pharmacological inhibition of the PI3K/Akt/mTOR axis (e.g., by juglone) similarly compromises oocyte maturation [81]. It also suppresses apoptosis by modulating Bcl-2 family members and caspases [37, 38].

For the resumption of meiosis, PI3K/Akt signaling plays a direct and indispensable role. Both Akt1 and Akt2 are present and functional in mouse oocytes [82]. Inhibition of Akt hinders germinal vesicle breakdown and severely disrupts meiotic progression [83]. Akt activity peaks at metaphase I, where it orchestrates the metaphase I-to-anaphase I transition [84]. A central mechanism involves Akt phosphorylating the APC (anaphase-promoting complex) co-activator FZR1 (fizzy and cell division cycle 20-related protein 1), which promotes the degradation of cyclin B and the consequent inactivation of the master regulator CDK1 (cyclin-dependent kinase 1)/Cyclin B, thereby driving the cell cycle forward [40–42]. Furthermore, activated mTORC1, downstream of PI3K/Akt, facilitates meiotic resumption by targeting rpS6 and eukaryotic initiation factor 4E to promote the protein synthesis required for this process [39]. The precision of this regulation is underscored by meiotic failures observed when upstream components, such as the nucleolar protein DCAF13 (DDB1- and CUL4-associated factor 13), are deficient [85, 86].

Environmental and iatrogenic modifiers of PI3K/Akt in ovarian function

During follicular development, environmental factors and chemicals can disrupt the PI3K/Akt signaling pathway, resulting in impaired follicular growth and ovarian dysfunction. The key pollutants, their mechanisms, and levels of evidence are summarized in Table 2.

Table 2.

Environmental pollutants and iatrogenic agents modulating the PI3K/Akt pathway in ovarian function

Pollutant / Agent	Primary Source(s)	Experimental Model	Affected PI3K/Akt Node(s)	Main Ovarian Effect(s)	Type of Evidence	Reference(s)
Perfluorooctane sulfonate (PFOS)	Cosmetics, shampoos, food packaging, and medical devices	Human granulosa-like KGN cell line	PI3K/Akt/mTOR ↓	Granulosa cell autophagy ↑, apoptosis ↑, and follicular development ↓	In vitro	[87, 88]
B[a]P/BPDE	Cigarette smoke, smoked/grilled foods	Mouse	PI3K/Akt ↓	Oxidative stress ↑; follicular development and maturation ↓	In vivo	[89]
Fine particulate matter (PM2.5)	Air pollution	Mouse	PI3K/Akt/FOXO3 ↑	Primordial follicle activation ↑, ovarian reserve ↓, and granulosa cell apoptosis ↑	In vivo	[90]
BPA	Plastics, PVC, food-can linings, dental sealants	Mouse oocytes & ovarian tissue	PI3K/Akt ↓ (context-dependent)	Follicular growth ↓, meiotic progression ↓, and premature follicle activation ↑	In vitro / In vivo	[91–94]
Cadmium	Heavy metal contamination	Chicken follicular granulosa cells	Akt/FOXO3 ↓ (via PTEN)	ROS accumulation ↑, granulosa cell apoptosis ↑, and follicular atresia	In vitro	[95]

↑ indicates activation or increase; ↓ indicates inhibition or decrease

In vitro: cell culture model; In vivo: animal model

Abbreviations: B[a]P Benzo[a]pyrene, BPDE Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide, BPA Bisphenol A, FOXO3 Forkhead box O3, KGN cell line Human granulosa-like tumor cell line (a model for studying human granulosa cell function), mTOR Mammalian target of rapamycin, PI3K Phosphoinositide 3-kinase, PFOS Perfluorooctane sulfonate, PM2.5 Fine particulate matter (particles with aerodynamic diameter ≤ 2.5 μm), PTEN Phosphatase and tensin homolog, PVC Polyvinyl chloride, ROS Reactive oxygen species

Exposure to perfluorooctane sulfonate, an environmental endocrine disruptor, inhibits the PI3K/Akt/mTOR signaling pathway in human ovarian granulosa cells. This leads to increased expression of autophagy (LC3-II/I) and apoptosis (Bax, cytochrome c, cleaved caspase-9) related proteins, while decreasing p62 and Bcl-2, ultimately inducing granulosa cell death and impairing follicular development [87, 88]. PM2.5 (fine particulate matter) can activate both the PI3K/Akt/FOXO3 and NF-κB (nuclear factor kappa-B) pathways, promoting primordial follicle activation and granulosa cell apoptosis, thereby diminishing ovarian reserve capacity [90].

Bisphenol A (BPA), a widespread environmental estrogen, can competitively bind to estrogen receptors, interfering with PI3K/Akt pathway activation and adversely affecting follicular growth and meiosis [91–93]. It can also enhance PI3K expression and Akt phosphorylation in primordial follicles, potentially leading to excessive activation and contributing to premature ovarian aging [94]. B(a)P (Benzo[a]pyrene) and its metabolite BPDE (benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide) inhibit PI3K/Akt activation, disrupt antioxidant defenses, induce oxidative stress, and impair follicular development [89]. Furthermore, the heavy metal cadmium modulates the PTEN/Akt/FOXO3 axis, inducing ROS accumulation and triggering granulosa cell apoptosis, leading to follicular atresia [95]. Collectively, these pollutants may compromise female reproductive health by targeting the PI3K/Akt pathway.

Current understanding of how environmental chemicals affect the PI3K/Akt pathway relies heavily on rodent models and in vitro systems, with a notable paucity of direct human epidemiological data linking specific exposures to ovarian pathology via this mechanism. This translational gap warrants careful consideration of several limitations. First, significant interspecies differences exist in toxicokinetics, hormonal regulation, and folliculogenesis—humans are mono-ovulatory, whereas rodents are poly-ovulatory, which may lead to differential pathway modulation [96–98]. Consequently, “safe” or “effective” thresholds established in animals require cautious extrapolation to humans. Second, many environmental agents, such as BPA, exhibit non-monotonic dose-response relationships, where low and high doses can produce opposing ovarian effects [99, 100]. Third, real-world human exposure is characterized by complex mixtures (e.g., co-exposure to BPA and phthalates) [101] and multiple routes (dietary, inhalation, dermal), which are not fully captured by studies of single compounds administered via one route. Finally, most toxicological studies employ acute, high-dose exposure paradigms, which do not reflect the chronic, low-dose exposure scenarios typical of human environmental contact. Future research should prioritize more human-relevant models, including long-term, low-dose, and mixture exposure studies, to better assess the risks these pollutants pose to ovarian health.

Therapeutic implications targeting the PI3K/Akt pathway in non-malignant ovarian disorders

The PI3K/Akt pathway, as a crucial regulator of follicular development and ovarian function, has emerged as a promising therapeutic target for non-malignant ovarian dysfunctions [102]. It is important to note that the efficacy data discussed below are predominantly derived from preclinical models (in vitro and animal studies), and robust clinical evidence in humans remains limited, as summarized in Table 3.

Table 3.

Targeting strategies of PI3K/Akt in non-malignant ovarian disorders

Intervention	Target Condition	Experimental Model/Subjects	Main PI3K/Akt-Related Effect(s)	Level of Evidence	Reference(s)
Metformin	PCOS	Rat	PI3K/Akt/mTOR ↑; granulosa cell autophagy & oxidative stress ↓	Preclinical	[103]
Dehydroepiandrosterone	POI	Rat	PI3K/Akt (via PTEN) ↑; follicular development ↑; apoptosis & inflammation ↓	Preclinical	[104]
Growth hormone	PCOS	Human granulosa cells (in vitro)	PI3K/Akt ↑; ROS & apoptosis ↓	Preclinical	[29]
Guizhi Fuling Wan + Rosiglitazone	PCOS	Rat	Modulates PI3K/Akt/NF-κB; ovarian architecture & follicle development ↑; inflammation ↓	Preclinical	[36]
Dingkun Pill	Chemo-induced POI	Mouse	PI3K/Akt/FOXO3 (via PTEN) ↑; restores estrous cycle; follicle & corpora lutea count ↑	Preclinical	[105]
Cangfudaotan Decoction	PCOS	Rat	IGF-1/PI3K/Akt ↑; improves insulin resistance & follicular development; inflammation ↓	Preclinical	[106]
Quercetin	POI	Rat	PI3K/Akt/FOXO3↑; AMH & estrogen ↑; oxidative stress ↓	Preclinical	[107]
Plumbagin	PCOS	Human granulosa cells (in vitro)	PI3K/Akt ↓; granulosa cell apoptosis ↑	Preclinical	[108]
Liquiritin	PCOS	Human granulosa cells (in vitro)	miR-206 ↑ ; PI3K/Akt ↓; proliferation ↓; apoptosis ↑	Preclinical	[109]
Melatonin	Chemo-induced POI	Rat	Modulates PTEN/PI3K/Akt/mTOR/AMPK; oxidative stress, apoptosis & inflammation ↓	Preclinical	[110]
Lithium	POI	Mouse	PI3K/Akt; promotes FOXO3 nuclear export ↑; growing follicles ↑	Preclinical	[23]
Theophylline derivative	POI (aging)	Mouse	cAMP/PI3K/Akt; promotes follicle activation ↑; MII oocytes & fertility ↑	Preclinical	[86]
Qilin Pill	POI	Rat	PI3K/Akt & MAPK ↓; restores estrous cycle; FSH & follicle depletion ↓	Preclinical	[111]
Ovarian tissue fragmentation/transplantation	POI / Diminished reserve	Human tissue / Xenograft	PI3K/Akt & disrupts Hippo ↑; promotes follicle activation & growth (risk of burnout)	Preclinical / Early Clinical	[58, 112]
PRP + Stem Cell activation/transplantation	POI	Human patients	PI3K/Akt ↑; resulted in follicles (64% of patients), oocytes (25%), and pregnancies (3)	Clinical	[113]
PI3K activator + PTEN inhibitor activation/transplantation	POI	Human patients	PI3K ↑; led to oocyte retrieval (4/14 patients) and one live birth	Clinical	[114]

The “Level of Evidence” is categorized as Preclinical (evidence derived from in vitro cell culture or animal model studies) or Clinical (evidence from studies involving human participants)

↑ indicates activation or upregulation of the pathway/effect; ↓ indicates inhibition or downregulation

Abbreviations: PCOS Polycystic Ovary Syndrome, POI Premature Ovarian Insufficiency, AKT (PKB) Protein Kinase B, AMPK AMP-activated Protein Kinase, AMH Anti-Müllerian Hormone, cAMP Cyclic Adenosine Monophosphate, FSH Follicle-Stimulating Hormone, FOXO3 Forkhead Box O3, IGF-1 Insulin-like Growth Factor 1, MAPK Mitogen-Activated Protein Kinase, miR-206 microRNA-206, mTOR Mammalian Target of Rapamycin, NF-κB Nuclear Factor Kappa, PI3K Phosphoinositide 3-Kinase, PRP Platelet-Rich Plasma, PTEN Phosphatase and Tensin Homolog, ROS Reactive Oxygen Species

PCOS

Several pharmacological and herbal interventions targeting the PI3K/Akt pathway have shown potential in PCOS models. Metformin, a widely used insulin sensitizer, reduces excessive autophagy in granulosa cells of PCOS rats via the PI3K/Akt/mTOR pathway, thereby alleviating ovarian oxidative stress [103]. Growth hormone activates PI3K/Akt signaling and inhibits ROS accumulation and apoptosis in in vitro cultured granulosa cells from PCOS patients [29].

Traditional Chinese Medicine (TCM) formulations have also demonstrated therapeutic effects in preclinical PCOS models. Guizhi Fuling Wan, when combined with rosiglitazone, improved ovarian architecture and promoted follicular development in a rat model of PCOS. Its effects, which include reducing inflammatory cytokines and elevating antioxidant enzymes, may be mediated through the PI3K/Akt/NF-κB pathway [36]. Similarly, Cangfudaotan decoction ameliorated PCOS symptoms in rats by improving insulin resistance and follicular development, potentially via the IGF-1-PI3K/Akt pathway [106].

Specific bioactive compounds from TCM can also modulate this pathway. Plumbagin and liquiritin induce apoptosis in human granulosa cells in vitro by inhibiting the PI3K/Akt pathway, thereby ameliorating polycystic ovarian pathology [108, 109].

POI and ovarian reserve

Strategies to enhance ovarian reserve or counteract POI also involve the PI3K/Akt axis. Dehydroepiandrosterone promotes follicular development in a rat model of POI by upregulating the PI3K/Akt pathway via PTEN modulation, reducing apoptosis and oxidative stress [104]. Melatonin protects against cisplatin-induced ovarian dysfunction in rats by regulating steroidogenesis, inflammation, apoptosis, oxidative stress, and multiple signaling nodes, including PTEN, PI3K/Akt, mTOR, and AMPK [110].

TCM approaches show similar promise. Dingkun Pill restored ovarian function in a mouse model of chemotherapy-induced POI by modulating PTEN and its downstream PI3K/Akt/FOXO3 pathway, leading to improved estrous cyclicity and increased follicle numbers [105]. Qilin Pill, a multi-herb formula, restored the estrous cycle and reduced follicle depletion in POI rats by concurrently inhibiting the MAPK and PI3K/Akt pathways [111]. Quercetin alleviated cyclophosphamide-induced POI in rats by enhancing the PI3K/Akt/FOXO3 pathway and reducing oxidative stress [107].

Emerging techniques like ovarian tissue activation and transplantation offer a direct translational avenue. Manipulation of both the PI3K/Akt and Hippo pathways is central to these strategies. For instance, tissue fragmentation disrupts Hippo signaling, while PI3K activators (e.g., PTEN inhibitors) directly stimulate the PI3K/Akt pathway, collectively promoting follicle activation [58, 112]. Promising early clinical results have been reported: one study using platelet-rich plasma and stem cells with tissue activation resulted in follicle development in 64% of POI patients and pregnancies in three women [113]. Another study using a PI3K activator and PTEN inhibitor led to successful oocyte retrieval in 4 out of 14 POI patients, with one live birth [114].

Overall, the PI3K/Akt pathway is a vital regulatory node in the treatment of non-malignant ovarian dysfunctions such as PCOS and POI, highlighting its potential as a target for innovative therapeutic strategies, although further clinical validation is warranted.

Future directions and knowledge gaps

The insights into the PI3K/Akt pathway reviewed herein are primarily derived from preclinical rodent models and in vitro systems, which, while invaluable, present inherent limitations for human translation. First, notable species differences exist. For instance, the role of FOXO3 in maintaining primordial follicle quiescence appears more absolute in mice than in the heterogeneous follicle populations of the human ovary [115–118]. Second, experimental models themselves have constraints; prolonged culture of granulosa cells can alter receptor expression, potentially skewing pathway activity data [119, 120]. Third, when considering therapeutic applications, the promising effects of TCM observed in preclinical studies face translational hurdles due to the complexity and lack of standardization of multi-component formulas. Similarly, emerging techniques like ovarian tissue activation and transplantation face the challenge of achieving controlled, balanced follicle activation to avoid premature reserve depletion [56, 121]. Fourth, a critical overarching gap is the paucity of direct evidence from human studies linking specific PI3K/Akt alterations to clinical reproductive outcomes.

To bridge these gaps, future research must prioritize several interconnected strategies. First, there is an urgent need to develop more human-relevant models and to conduct high-quality clinical studies, which are essential for validating preclinical findings and directly linking pathway biology to patient outcomes. Concurrently, efforts should focus on deconstructing complex TCM formulations to identify their key bioactive compounds, enabling the development of standardized, targeted therapies. Furthermore, the refinement of protocols for ovarian tissue activation and transplantation must advance. This may include optimizing the safety and exposure parameters of existing pharmacological activators, as well as exploring non-pharmacological activation methods, such as those advanced in human follicle culture systems [122]. A paramount focus must be placed on achieving precise spatiotemporal control and thoroughly evaluating long-term safety to mitigate the risk of premature ovarian reserve exhaustion. Finally, innovating targeted delivery strategies, such as those utilizing stem cell-derived exosomes [123], holds promise for enhancing the efficacy and safety of pathway modulation. Pursuing these directions cohesively is essential for translating our mechanistic understanding of the PI3K/Akt pathway into safe, effective, and personalized clinical strategies for non-malignant ovarian disorders.

Conclusion

The PI3K/Akt signaling pathway is a crucial regulator of ovarian follicular development, orchestrating essential biological processes such as primordial follicle activation, granulosa cell proliferation, differentiation, apoptosis, oocyte growth, and meiotic resumption. This pathway influences multiple facets of follicular growth, recruitment, selection, and ovulation. Dysregulation of this pathway is associated with significant non-malignant ovarian disorders, including PCOS and POI, highlighting the necessity of understanding these mechanisms for effective diagnosis and treatment. Environmental toxins further exacerbate these conditions by impairing the integrity of the PI3K/Akt signaling pathway, leading to granulosa cell apoptosis and diminished ovarian reserve. However, both Western medicine and TCM present promising avenues for therapeutic intervention targeting this pathway, offering a multifaceted approach to restore ovarian function and improve fertility outcomes. Additionally, techniques such as ovarian tissue activation and transplantation represent important potential approaches for rescuing ovarian reserve in patients with diminished ovarian function or POI. Consequently, the PI3K/Akt pathway is increasingly recognized as a strategic target for pharmacological interventions and bioengineering strategies aimed at ovarian protection and treatment. Continued in-depth investigation into its regulatory roles in follicular development, coupled with the development of more effective therapeutic agents and techniques, will substantially advance the preservation of female reproductive health and the enhancement of fertility potential.

Abbreviations

PI3K

Phosphoinositide 3-kinase

Akt

Protein kinase B

POI

Premature ovarian insufficiency

PCOS

Polycystic ovary syndrome

CNKI

China National Knowledge Infrastructure

MeSH

Medical subject headings

PIP2

Phosphatidylinositol 4,5-bisphosphate

PIP3

Phosphatidylinositol 3,4,5-trisphosphate

FOXO

Forkhead box O

mTOR

Mammalian target of rapamycin

PTEN

Phosphatase and tensin homolog

IGF-1

Insulin-like growth factor 1

CDC42

Cell division cycle 42

YAP

Yes-associated protein

TAZ

Transcriptional coactivator with PDZ-binding motif

MAPK

Mitogen-activated protein kinase

ERK

Extracellular signal-regulated kinase

JAK/STAT

Janus kinase/signal transducer and activator of transcription

mTORC1

Mammalian target of rapamycin complex 1

rpS6

Ribosomal protein S6

IRS

Insulin receptor substrate

FSH

Follicle-stimulating hormone

SOD

Superoxide dismutase

GSH-Px

Glutathione peroxidase

ROS

Reactive oxygen species

Bmal1

Brain and muscle ARNT-like protein 1

StAR

Steroidogenic acute regulatory protein

CYP11A1

Cytochrome P450 family 11 subfamily A member 1

CYP19A1

Cytochrome P450 family 19 subfamily A member 1

PDK1

Phosphoinositide-Dependent Protein Kinase 1

FZR1

Fizzy and cell division cycle 20-related protein 1

DCAF13

DDB1- and CUL4-associated factor 13

BPA

Bisphenol A

PM2.5

Fine particulate matter

B(a)P

Benzo[a]pyrene

BPDE

Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide

TCM

Traditional Chinese Medicine

SH

Src homology

TSC1

Tuberous sclerosis complex 1

TSC2

Tuberous sclerosis complex 2

NFE2L2

Nuclear factor erythroid 2-related factor 2

APC

Anaphase-promoting complex

MPF

Maturation-promoting factor

eIF4E

Eukaryotic initiation factor 4E

S6K

Ribosomal protein S6 kinase

NF-κB

Nuclear factor kappa B

HO-1

Heme oxygenase 1

NQO1

NAD(P)H dehydrogenase [quinone] 1

GCLC

Glutamate-cysteine ligase, catalytic subunit

FasL

Fas ligand

BimEL

Bcl-2 interacting mediator of cell death, el isoform

Bax

Bcl-2-associated X protein

Bcl-2

B-cell lymphoma 2

CDK1

Cyclin-dependent kinase 1

CDK2

Cyclin-dependent kinase 2

Authors’ contributions

Jiaqi He was responsible for the selection of the topic and writing of the manuscript. Hongxia Gao contributed to literature retrieval and manuscript revision. Xiaoyan Pan was responsible for research guidance, manuscript revision, and funding support. All authors read and approved the final manuscript.

Funding

This study was supported by the Scientific and Technological Research Project of Jilin province (20240305074YY) and the Industrial Technology Research and Development Project of Jilin Province Development and Reform Commission (2023C027-8).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.