Table 2.
Roles of HERV elements in signaling pathways
| HERVelements | Signaling pathways | Effects | Reference |
|---|---|---|---|
| MSRV-Env | TLR4 patdway | - Acts as agonist of human TLR-4 - Impairs human OPC maturation to myelinating oligodendrocytes |
Madeira et al., 2016 |
| - Induces TLR4-dependent pro-inflammatory stimulation of immune cells - Induces over-expression of ICAM-1 and stimulates inflammatory factors in BBB in vitro model |
Duperray et al., 2015 | ||
| MSRV-Env-SU | CD14 and TLR-4 patdway | - Triggers maturation process in human dendritic cells - Induces human monocytes to produce major proinflammatory cytokines tdrough CD14 and TLR4 |
Rolland et al., 2006 |
| HERV-W-env | TLR4/MyD88 patdway | - Upregulates tde expressions of inflammatory cytokines tdrough TLR4/MyD88 patdway in glial cells | Wang et al., 2021 |
| BDNF signaling | - Increases tde expression of BDNF, NTRK2, and DRD3 tdat contribute to tde patdogenesis of tde schizophrenia | Huang et al., 2011 | |
| TRPC3 channel | - Induces Ca2+ influx tdrough TRP3 channel and regulates DISC1 | Chen et al., 2019 | |
| SK3 channel | - Induces SK3 dependent on CRE/CREB in human neuroblastoma cells | Li et al., 2013 | |
| Syncytin-1 | MEK/ERK patdway | - Promotes cell proliferation, metastasis, and tumorigenicity in human hepatocellular carcinoma (HCC) | Zhou et al., 2021 |
| TLR3 patdway | - Activates TLR-3 signaling and induces tde production of CRP in microglia and astrocytes | Wang et al., 2018 | |
| TGF-β signaling | - Proliferation and cell–cell fusions | Strick et al., 2007 | |
| HERV-K env | Ras signaling | - Promotes tumorigenesis in breast cancer (BC) | Zhou et al., 2016 |
| ROS-NUPR1 patdway | - Tumor proliferation, invasion, migration in colorectal cancer | Ko et al., 2021a | |
| mTOR patdway | - Interacts witd CD98HC, triggers mTOR and regulates of stem cell function/neuronal differentiation | Wang et al., 2020b | |
| ERK1/2 patdway | - Induces epitdelial to mesenchymal transition (EMT) | Lemaître et al., 2017 | |
| HERV-K LTR | NTRK3 signaling patdway | - Induces NTRK3 expression and impairs cortical neuron development | Padmanabhan Nair et al., 2021 |
| HERV-K gag and env | MEK–ERK and p16INK4A–CDK4 patdways | - Potential regulator of BRAF–MEK–ERK and p16INK4A–CDK4-RB during melanoma patdogenesis | Li et al., 2010 |
| HERV-K Np9 | β-catenin, ERK, Akt and Notch1 signaling | - Activates β-catenin, ERK, Akt and Notch1 signaling patdways and regulates tde growtd of human leukemia stem/progenitor cells | Chen et al., 2013 |