SIRT5 affects lipid accumulation in cells of a metabolic-associated fatty liver disease model by regulating the succinylation status of HSPD1

Abstract

Background

Metabolic-associated fatty liver disease (MAFLD) is a liver disease characterized by abnormal lipid metabolism. This study investigated the effects of succinylation on hepatocyte steatosis and lipid storage in MAFLD in vitro.

Methods

mRNA and protein levels of two desuccinylases (SIRT5 and SIRT7) and three succinylases (KAT2A, KAT3B, and CPT1A) were evaluated in blood samples from MAFLD patients. Exposure of HepG2 and Huh7 cells to free fatty acids (FFA) was established to mimic MAFLD in vitro. Triglyceride (TG) content, total cholesterol (TC) content, and lipid accumulation were combined to evaluate lipid metabolism. HSPD1 protein was pulled-down using immunoprecipitation (IP). Co-immunoprecipitation (co-IP) combined with immunofluorescence was used to verify the interaction between SIRT5 and HSPD1.

Results

SIRT5 was prominently down-regulated in blood samples of patients with MAFLD. FFA exposure induced lipid metabolism dysfunction by increasing TC, TG levels, and the number of Oil Red O and BODIPY-stained lipid droplets. Overexpression of SIRT5 significantly attenuated the effects of FFA on lipid metabolism. HSPD1 was found to interact with SIRT5, which mediated HSPD1 desuccinylation and accelerated its protein degradation. Overexpression of HSPD1 sharply reversed the protective effects of elevated SIRT5 on cellular steatosis in HepG2 and Huh7 cells. SIRT5 directly interacted with HSPD1, and elevated SIRT5 levels reduced HSPD1 protein stability through desuccinylation modification.

Conclusion

SIRT5-mediated desuccinylation of HSPD1 protects against hepatic steatosis in MAFLD model cells, suggesting that targeting SIRT5 and HSPD1 may represent a novel therapeutic strategy for preventing and treating MAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-025-00776-7.

Introduction

Metabolic-associated fatty liver disease (MAFLD) is a pathological syndrome characterized by hepatocyte steatosis and lipid storage [1, 2]. MAFLD is the most common chronic liver disease worldwide, with an estimated global prevalence of 25%, and its prevalence continues to rise with the ongoing obesity epidemic [3]. Among individuals with obesity and type 2 diabetes, the prevalence of MAFLD reaches 60% and 80%, respectively [3]. Genetic variations, such as those in the.

PNPLA3 gene, may increase susceptibility to MAFLD [4, 5]. Targeting genes involved in lipid metabolism is critical for understanding and managing this condition.

Post-translational modification (PTM) plays a pivotal role in the pathogenesis and progression of MAFLD [6]. These modifications dynamically regulate protein function, stability, and interactions, influencing key processes such as lipid metabolism, inflammatory responses, and fibrosis [7]. Lipid metabolism is governed by diverse enzymes and proteins, and their PTMs may significantly impact the onset and progression of MAFLD [8, 9]. Succinylation, a PTM that alters protein structure and function [10, 11], is closely linked to hepatic metabolism [12]. Investigating the role of succinylation in MAFLD not only sheds light on its molecular mechanisms but also provides a theoretical foundation for developing novel diagnostic biomarkers and therapeutic strategies.

Heat shock protein D1 (HSPD1) is a mitochondrial protein that plays a critical role in cellular metabolism and stress response [13]. Mitochondrial dysfunction is a key mechanism underlying MAFLD [14]. HSPD1 also contributes to various stress responses, including endoplasmic reticulum stress and oxidative stress [15]. In MAFLD, high-fat diets and metabolic disorders contribute to elevated endoplasmic reticulum stress and oxidative stress, leading to inflammation and hepatocyte damage [16]. Therefore, HSPD1 may serve as a biomarker and potential therapeutic target for MAFLD progression. A deeper understanding of HSPD1’s role in MAFLD could elucidate its molecular mechanisms and provide a theoretical foundation for developing novel diagnostic biomarkers and therapeutic strategies.

In this study, we hypothesized that HSPD1 may be regulated by succinylation and could influence hepatic steatosis in vitro. Our data demonstrate that HSPD1 directly interacts with SIRT5, a canonical desuccinylase, and SIRT5-mediated desuccinylation of HSPD1 protects MAFLD model cells from lipotoxicity-induced damage. In conclusion, targeting HSPD1 and SIRT5 in MAFLD may represent a promising therapeutic strategy for prevention and treatment.

Methods and materials

Clinical sample

Nineteen patients diagnosed with MAFLD at the University-Town Hospital of Chongqing Medical University were enrolled, and twenty-two healthy volunteers undergoing routine physical examinations at our hospital were included as healthy control (HC). Corresponding clinical characteristics were recorded (Table 1). This study was approved by the Ethics Committee of the hospital, and written informed consent was obtained from all participants. Peripheral venous blood samples were subsequently collected.

Table 1.

Demographic and clinical characteristics of healthy controls and NAFLD patients

Parameters	Healthy controls N = 22	NAFLD patients N = 19	P value
Sex	13	8	0.278
Male	9	11
	Mean ± SD	Mean ± SD
Age	35 ± 8.5	47.1 ± 13.0	< 0.001
BMI (kg/m2)	22.2 ± 1.8	26.5 ± 5.6	0.001
FBS (mg/dl)	87.0 ± 7.6	112.2 ± 26.0	< 0.001
Creatinine (mg/dl)	1.0 ± 0.2	1.0 ± 0.2	0.835
BUN (mg/dl)	11.3 ± 2.5	11.2 ± 3.4	0.906
Uric acid (mg/dl)	5.2 ± 1.8	5.9 ± 1.5	0.191
Cholesterol (mg/dl)	186.4 ± 39.4	203.9 ± 39.4	0.188
Triglycerides (mg/dl)	74.8 ± 43.0	135.7 ± 88.8	0.007
HDL-C (mg/dl)	62.9 ± 17.9	48.1 ± 13.2	0.005
LDL-C (mg/dl)	115.9 ± 29.2	117.1 ± 39.3	0.910
VLDL-C (mg/dl)	14.7 ± 8.2	31.7 ± 12.7	< 0.001
Non-HDL-C (mg/dl)	132.4 ± 39.2	156.0 ± 57.6	0.128
AK (IU/L)	95.8 ± 18.4	96.4 ± 36.0	0.948
TB (mg/dl)	0.8 ± 0.3	0.8 ± 0.5	0.539
CB (mg/dl)	0.1 ± 0.03	0.2 ± 0.1	< 0.001
UB (mg/dl)	0.7 ± 0.4	0.8 ± 0.4	0.304
Total protein (g/dl)	7.8 ± 0.4	8.2 ± 0.7	0.034
AST (IU/L)	20.4 ± 6.8	43.5 ± 24.3	< 0.001
ALT (IU/L)	40.1 ± 15.7	83.7 ± 43.4	< 0.001

Plasmids and antibodies

The pcDNA3.1-SIRT5 and pcDNA3.1-HSPD1 vectors were constructed by inserting full-length SIRT5 and HSPD1 into the pcDNA3.1 vector, respectively. An empty pcDNA3.1 vector was used as the expression control. Rabbit anti-KAT2A monoclonal antibody (#3305, 1:1000), rabbit anti-KAT3B monoclonal antibody (#4771, 1:1000), anti-CPT1A antibody (#97361, 1:1000), anti-SIRT5 antibody (#8779, 1:1000), anti-SIRT7 antibody (#5360, 1:1000), rabbit anti-HSPD1 monoclonal antibody (#12165, 1:1000), and anti-GAPDH antibody (#2118, 1:1000) were obtained from Cell Signaling Technology (Danvers, MA, USA). Normal rabbit IgG (NI01) was sourced from Merck Millipore (Shanghai, China). Rabbit anti-succinyllysine antibody (PTM-401, 1:500) was purchased from PTM Biolabs (Hangzhou, Zhejiang, China).

Cell culture, transfection, and treatment

HepG2 and Huh7 cells, known for their sensitivity to lipid accumulation [17, 18], were obtained from ATCC. Cells were cultured in Dulbecco’s Modified Eagle Medium (DMEM; Invitrogen, USA) supplemented with 10% fetal bovine serum (FBS; Gibco, Grand Island, NY, USA), 100 units/mL penicillin, and 100 µg/mL streptomycin. HepG2 and Huh7 cells were seeded in 6-well plates at a density of 2 × 10⁵ cells per well. The pcDNA3.1-SIRT5 (oe-SIRT5), pcDNA3.1-HSPD1 (oe-HSPD1), pcDNA3.1 empty vector (oe-NC), non-targeting control shRNA (shNC) or shRNA targeting HSPD1 (shHSPD1) were transfected into the cells using Lipofectamine 2000 according to the manufacturer’s protocol. To investigate the role of SIRT5/HSPD1 in MAFLD in vitro, cells were treated with 1 mM free fatty acids (FFA; a 2:1 mixture of oleic acid and palmitic acid) [18–20] for 24 h following an overnight transfection.

RNA extraction and quantitative real-time PCR analysis

Total RNA was extracted from blood samples using the RiboPure™-Blood Kit (Thermo Fisher Scientific, Waltham, MA, USA) and from HepG2 and Huh7 cells using TRIzol reagent (Invitrogen, Carlsbad, CA, USA). cDNA was synthesized using the High Capacity cDNA Reverse Transcription Kit (Applied Biosystems, Waltham, MA, USA). Quantitative real-time PCR was performed to detect gene expression levels using SYBR Green PCR Master Mix (Takara, Shiga, Japan) on the StepOnePlus Real-Time PCR System (Applied Biosystems, Waltham, MA, USA).

Protein evaluation, western blot, immunoprecipitation (IP) and co-immunoprecipitation (co-IP)

Protein was extracted from HepG2 and Huh7 cells using RIPA lysis reagent (Thermo Fisher Scientific, Waltham, MA, USA), while protein from blood samples was isolated using a whole-blood protein extraction kit (EX1200; Solarbio, Beijing, China). The extracted proteins were resolved by 10% SDS-PAGE and transferred onto PVDF membranes (Merck, Shanghai, China). Membranes were blocked with 5% skim milk solution and subsequently incubated with primary antibodies followed by HRP-conjugated secondary antibodies. Relative protein expression levels were quantified using ImageJ software. For IP, protein G agarose beads were incubated with lysates containing anti-HSPD1 antibody for 1 h at 4 °C. The bead-antibody complexes were then boiled at 95 °C for 5 min to elute bound proteins. Co-IP was performed to validate the interaction between SIRT5 and HSPD1 proteins. Specific antibodies were conjugated to protein G agarose beads through overnight incubation at 4 °C. Finally, both input lysates and immunoprecipitated samples were collected for subsequent analysis.

Protein stability evaluation

The HepG2 cell culture medium was removed, and fresh complete culture medium containing cycloheximide (CHX, 50 µg/mL; Selleck, Houston, TX, USA) was added [21]. Cells were collected at various time points (0, 6, 12, 18, and 24 h) to isolate total cellular protein, and the HSPD1 protein expression levels were analyzed via Western blot analysis.

Evaluation of total triglyceride (TG) and cholesterol (TC) concentration

TC levels were quantified using a TC content detection kit (BC1985; Solarbio, Beijing, China) via spectrophotometry, while TG levels were determined using a Triglyceride-Glo™ Assay Kit (J3160) via bioluminescence, according to the manufacturer’s instructions.

Oil red O staining and bodipy staining

The HepG2 and Huh7 cells were fixed in 4% paraformaldehyde solution for 15 min, followed by incubation in isopropyl alcohol solution for 5 min. Subsequently, Oil Red O staining solution (G1015; Servicebio Technology, Wuhan, China) was applied for lipid visualization. For Bodipy staining, HepG2 and Huh7 cells were incubated with 4 µM Bodipy staining solution (Thermo Fisher Scientific) in the dark for 15 min [22]. Cellular lipid accumulation was visualized under a light microscope (Leica DM 2500, Germany).

Immunofluorescence

The HepG2 cells (1 × 10⁵/mL) were seeded into a 35 mm dish. After fixation with 4% paraformaldehyde for 15 min, cells were blocked with 5% fetal bovine serum (FBS) for 1 h. Subsequently, the cells were incubated with anti-SIRT5 and anti-HSPD1 primary antibodies at 4 °C overnight, followed by incubation with an Alexa Fluor^® 647-conjugated goat anti-rabbit IgG secondary antibody for 2 h. Finally, the cells were mounted in DAPI-containing mounting medium for nuclear staining.

Surface plasmon resonance (SPR) analysis

Recombinant human HSPD1 protein was immobilized onto a Series S Sensor Chip CM5 (Cytiva, Marlborough, MA, USA) using the amine coupling kit (#BR-1008-39, GE Healthcare,) according to the manufacturer’s instructions. Briefly, the chip surface was activated with a mixture of N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) at a flow rate of 10 µL/min for 7 min. Recombinant HSPD1 (20 µg/mL in 10 mM sodium acetate buffer, pH 4.5) was then injected until the immobilization level reached approximately 8,000–10,000 RU. Remaining active esters were blocked by injection of 1 M ethanolamine-HCl (pH 8.5). For binding analysis, purified recombinant SIRT5 protein was serially diluted in HBS-EP + buffer (10 mM HEPES, 150 mM NaCl, 3 mM EDTA, 0.05% v/v surfactant P20, pH 7.4) to concentrations of 7.8, 15.6, 31.25, 62.5, and 125 nM. Each concentration was injected over the HSPD1-coated and control (ethanolamine-blocked) surfaces at 30 µL/min for 180 s, followed by dissociation for 300 s. Regeneration was performed using a 30-s pulse of 10 mM glycine-HCl (pH 2.0). All experiments were conducted at 25 °C using a Biacore T200 instrument (Cytiva). Sensorgrams were double-referenced and fitted to a 1:1 Langmuir binding model using Biacore Evaluation Software (version 3.3).

Statistical analysis

Data were analyzed with GraphPad Prism 7. Statistical significance was determined by using unpaired Student t test (two groups) or one-way ANOVA (> two groups). p < 0.05 was deemed significant.

Results

SIRT5 is downregulated in blood samples of patients with MAFLD

First, patients with MAFLD and HC subjects were enrolled. As shown in Table 1, significant differences in age distribution and body mass index were observed between the two groups, whereas no difference in sex was noted. Additionally, we observed the following changes in lipid levels: The level of triglycerides was significantly upregulated (p = 0.007). The level of high-density lipoprotein cholesterol (HDL-C) was significantly downregulated (p = 0.005). The level of very-low-density lipoprotein cholesterol (VLDL-C) was significantly upregulated (p < 0.001). There were no significant differences in other lipids such as total cholesterol and low-density lipoprotein cholesterol (LDL-C) between MAFLD patients and the healthy control group. Protein succinylation has been implicated in MAFLD progression [23]. We quantified mRNA and protein levels of two desuccinylases and three succinylases in blood samples from HC and MAFLD subjects. SIRT5 expression was significantly downregulated in the MAFLD group compared to the HC group (Fig. 1A–G). However, no significant differences were observed in SIRT7, KAT2A, KAT3B, or CPT1A levels between MAFLD patients and healthy controls.

Fig. 1.

Expression of desuccinylase and succinylase in blood samples of HC and MAFLD subjects. A-E PCR analysis was carried out to determine the mRNA levels of two desuccinylase and three succinylase in blood samples of HC and MAFLD subjects. ^***p < 0.001 F-G Representative protein bands and quantitative analysis of KAT2A, KAT3B, CPT1A, SIRT5 and SIRT7 levels in blood samples of HC and MAFLD subjects. ^***p < 0.001

Overexpression of SIRT5 improves FFA-induced cellular steatosis in MAFLD model cells

Under normal physiological conditions, the supply of FFA and the synthesis and secretion of TG maintain a dynamic equilibrium. When TG synthesis from FFA in hepatocytes exceeds its degradation or secretion, the excess TG accumulates in liver cells, forming lipid droplets. To investigate the role of SIRT5 in hepatic steatosis, its effects were analyzed in an MAFLD cell model. First, SIRT5 was successfully overexpressed in HepG2 and Huh7 cells, as confirmed by PCR analysis (Fig. 2A). FFA treatment significantly increased TG (Fig. 2B), TC (Fig. 2C), and lipid accumulation levels (Fig. 2D–E) in both cell lines, indicating that FFA-induced hepatic steatosis was effectively modeled. Furthermore, upregulation of SIRT5 significantly reduced TC, TG, and lipid accumulation in FFA-treated cells, demonstrating that SIRT5 overexpression ameliorates hepatic steatosis in MAFLD cell models.

Fig. 2.

Regulatory effects of SIRT5 on hepatic steatosis. A PCR analysis was carried out to evaluate the mRNA levels of SIRT5 in HepG2 and Huh7 cells after transfection. ^***p < 0.001. B-C TG and TC content of HepG2 and Huh7 cells of each group were accessed by ELISA.^***p < 0.001 (vs. control), ^###p < 0.001 (vs. FFA + oe-NC). D-E Images and quantitative analysis of Oil red O staining and BODIPY staining of HepG2 and Huh7 cells.^***p < 0.001 (vs. control), ^###p < 0.001 (vs. FFA + oe-NC)

Repression of HSPD1 function by SIRT5-mediated desuccinylation in response to hepatic steatosis

HSPD1 is a newly reported gene associated with hepatic cell death and may represent a novel biomarker for MAFLD diagnosis [24, 25]. Both the protein levels and succinylation levels of HSPD1 in blood samples from MAFLD subjects were significantly higher than those in HC group (Fig. S1A and B). Meanwhile, both the protein levels and succinylation levels of HSPD1 in FFA treated HepG2 cells were significantly higher than those in control group (Fig. S1C and D). To explore whether SIRT5 mediates HSPD1 desuccinylation and thereby regulates lipid metabolism in MAFLD model cells, we conducted further investigations. Overexpression of SIRT5 significantly reduced both the protein levels and succinylation levels of HSPD1, indicating that SIRT5 promotes HSPD1 desuccinylation (Fig. 3A and B). co-IP experiments confirmed endogenous interaction between SIRT5 and HSPD1 (Fig. 3C and D). Immunofluorescence imaging of hepatocytes further demonstrated that SIRT5 colocalizes with HSPD1 in the cytoplasm (Fig. 3E). SPR analysis also confirmed a direct and high-affinity interaction between SIRT5 and HSPD1 (Fig. 3F). Moreover, SIRT5 overexpression accelerated HSPD1 protein degradation (Fig. 3G and H). These findings prompted us to hypothesize that HSPD1 may contribute to dysregulated lipid metabolism. HSPD1 levels were then successfully downregulated in HepG2 and Huh7 cells, as verified by PCR analysis (Fig. S2A). Inhibition of HSPD1 significantly reduced TC, TG, and lipid accumulation in FFA-treated cells (Fig. S2B - E). HSPD1 was then successfully overexpressed in HepG2 and Huh7 cells, as verified by PCR analysis (Fig. 4A). Notably, elevated HSPD1 significantly counteracted the effects of SIRT5 overexpression on hepatic steatosis, as evidenced by reduced TC and TG levels, as well as decreased numbers of Oil Red O- and BODIPY-stained cells (Fig. 4B–G). Specifically, HSPD1 overexpression reversed SIRT5-induced hepatic steatosis through reductions in TC and TG levels and diminished lipid accumulation markers (Fig. 4B–G).

Fig. 3.

SIRT5 leads to HSPD1 desuccinylation. A-B Western blot was carried out to evaluate the HSPD1 protein levels and the succinylation level of HSPD1. C-D co-IP was performed to verify the interaction between SIRT5 and HSPD1. E The co-locationof SIRT5 and HSPD1 obtained by the immunofluorescence method. F SPR analysis of the direct binding between SIRT5 and HSPD1. G-H Representative protein bands and quantitative analysis of protein degradation of HSPD1 when SIRT5 was overexpressed. ^***p < 0.001

Fig. 4.

SIRT5-mediated hepatic steatosis function is reversed by the elevation of HSPD1. A PCR analysis was carried out to evaluate the mRNA levels of HSPD1 in HepG2 and Huh7 cells after transfection. ^***p < 0.001. B-C TG and TC content of HepG2 and Huh7 cells of each group were accessed by ELISA. ^***p < 0.001 (vs. control), ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 (vs. FFA + oe-NC). D-G Images and quantitative analysis of Oil red O staining and BODIPY staining of HepG2 and Huh7 cells. ^***p < 0.001 (vs. control), ^#p < 0.05, ^###p < 0.001 (vs. FFA + oe-NC)

Discussion

In the current work, downregulated SIRT5 in MAFLD induced lipid accumulation in hepatocytes. Notably, SIRT5 reduced HSPD1 succinylation, and HSPD1 overexpression effectively reversed the protective effects of elevated SIRT5 against hepatic steatosis.

Sirtuins constitute a family of evolutionarily conserved deacylases (SIRT1-7) that regulate diverse pathological processes [26, 27]. SIRT1, SIRT2, SIRT3, SIRT4, and SIRT6 function as deacylases for multiple metabolic regulators, while SIRT5 and SIRT7 specifically serve as desuccinylases and deacetylases [28, 29]. Particularly, SIRT5 modulates key metabolic pathways including glycolysis and fatty acid β-oxidation through post-translational modification of target proteins [30]. Recent studies have demonstrated that SIRT5 deficiency promotes enzymatic succinylation of β-oxidation-related proteins, contributing to chronic metabolic disorders such as obesity, type 2 diabetes, and MAFLD [31, 32]. Consequently, we hypothesized that SIRT5’s desuccinylase activity might represent a critical regulatory mechanism in MAFLD pathogenesis. The significant downregulation of SIRT5 observed in MAFLD models, coupled with its protective effects against hepatic steatosis when overexpressed, aligns with findings in steatotic disease research. For example, Du Y et al. demonstrated that sustained SIRT5 upregulation in murine models ameliorated hepatic steatosis through succinylation inhibition [33]. Additionally, SIRT5 has been shown to mitigate peroxisome-induced oxidative stress in liver protection mechanisms [29]. Our research findings are consistent with previous studies, which suggest that overexpression of SIRT5 can alleviate FFA induced lipid accumulation in liver cells, supporting its protective role.

Heat shock proteins (HSPs) are evolutionarily highly conserved, ubiquitous, and abundant proteins. They play critical roles in cellular resistance to hypoxia, ischemia, inflammation, and extracellular stressors [34]. For example, naringin upregulated HSP27 levels in rat livers and suppressed hepatic lipid degeneration [35]. The effects of HSP72 on inflammatory mediator expression and lipid uptake in macrophages have also been reported [36]. Recently, HSPD1 (also known as HSP60) has been identified as a key regulator of MAFLD progression [25]. HSP60 modulates hepatic lipogenesis and insulin resistance via the mTORC1-SREBP1 signaling pathway [37]. Mitochondrial HSP60 enhances fatty acid oxidation to alleviate MAFLD by maintaining SIRT3 signaling [38]. Huang YH et al. further proposed that HSP60 may represent a promising therapeutic target for MAFLD improvement [39]. Based on these findings, we hypothesized that HSPD1 succinylation might be regulated by SIRT5. Our data demonstrated that SIRT5 interacts with HSPD1, resulting in HSPD1 desuccinylation. As predicted, HSPD1 overexpression significantly suppressed hepatic lipogenesis and counteracted the protective effects of SIRT5 overexpression. Another study has shown that HSPD1 is inhibited in human fatty liver, while overexpression of HSPD1 in mouse models can inhibit steatosis [38]. This seems to contradict our research findings. However, the apparent contradiction may be reconciled by considering the post-translational regulation of HSPD1, particularly lysine succinylation. While total HSPD1 levels may vary across studies, its functional outcome could depend on the balance between inactive and active forms. In our study, SIRT5-mediated desuccinylation promotes HSPD1 degradation, suggesting that the succinylated form of HSPD1 is more stable and potentially gain-of-function in promoting steatosis. In contrast, the protective effects observed in other models might reflect overexpression of non-succinylated or differently modified HSPD1 that retains chaperone activity without promoting lipogenesis. Therefore, rather than contradicting previous findings, our data suggest a context- and modification-dependent role for HSPD1 in MAFLD, where SIRT5-mediated desuccinylation acts as a molecular switch to suppress its pro-steatotic activity. Interestingly, acetylation and succinylation are two major post-translational modifications of proteins, both involving the addition of an acyl group to a lysine residue. On specific lysine residues, these modifications may compete for occupancy, thereby modulating protein function. Acetylation and succinylation likely collaborate in regulating diverse cellular processes, including metabolism, signaling, and gene expression. Notably, SIRT5 functions not only as a desuccinylase but also as a deacetylase [40]. Whether SIRT5 regulates HSPD1 function through deacetylation and whether a competitive relationship exists between these two modifications requires further investigation.

One limitation of this study is that the sample size was relatively small, which may have limited the statistical power and generalizability of our results. Nevertheless, our findings are consistent with those of existing studies in the literature regarding the roles of SIRT5 and HSPD1 in lipid metabolism. Future studies should include patient populations with larger sample sizes to validate our findings and further explore the mechanisms of action of SIRT5 and HSPD1 in the development of MAFLD.

Conclusion

In summary, SIRT5 binds to HSPD1 and reduces its protein stability by desuccinylating HSPD1. This mechanism promotes hepatic lipogenesis in MAFLD model cells. Therefore, targeting HSPD1 and SIRT5 represents a promising therapeutic strategy for alleviating MAFLD.

Authors’ contributions

All authors participated in the design, interpretation of the studies and analysis of the data and review of the manuscript. Y L drafted the work and revised it critically for important intellectual content; Q P was responsible for the acquisition, analysis and interpretation of data for the work; B L and B X made substantial contributions to the conception or design of the work. All authors read and approved the final manuscript.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was carried out after approval by the Ethics Committee of University-Town Hospital of Chongqing Medical University. This study was performed in line with the principles of the Declaration of Helsinki. Informed consent was obtained from all individual participants included in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.