Table 5.
Microglial and neuropathic pain-related gene expression
| Gene | M/Y | Microglial | Pain | Function |
|---|---|---|---|---|
| ABCA1 | 1.62 | Y | Y | Transporter of cholesterol and other lipids |
| AIF1 | 1.53 | Y | Y | Forms complexes with L-fimbrin in membrane ruffles and phagocytic cups; may modulate actin reorganization, facilitates cell migration and phagocytosis |
| ANXA3 | 1.55 | Y | Y | Annexin family member; up-regulated following tissue injury |
| ATF3 | 1.73 | Y | Y | Complexes with other transcriptional regulators; up-regulated in response to injury; negative regulator of TLR signaling; suppresses innate immune response |
| BLNK | 1.68 | Y | Cytoplasmic linker protein important in B cell development | |
| C1QA | 1.61 | Y | Y | Part of C1q complex; initial component of classic pathway |
| C1QB | 1.59 | Y | Y | Part of C1q complex |
| C1QC | 1.52 | Y | Y | Part of C1q complex |
| C4A | 1.98 | Y | Y | Cleaved by C1S; combines with C2 cleavage product forms C4b2b complex |
| CAMK2B | 0.64 | Y | Y | Ca2+/calmodulin-dependent protein kinase |
| CD163 | 1.59 | Y | M2 state microglial marker (aka, ED2); Alt priming gene | |
| CD37 | 1.54 | Y | Y | Interacts with dectin; regulates PAMP induced IL6 production; microglial sensome |
| CD53 | 1.71 | Y | Y | Contributes to transduction of CD2-generated signals in T cells |
| CD74 | 1.85 | Y | Y | Invariant MHCII component; processes receptor bound PAMP’S and DAMP’s for presentation to T cells |
| CSF3R | 1.59 | Y | Y | Binds GCSF, which increases M2 state marker expression, and inhibits pro-inflammatory cytokine expression, while promoting neurotrophic factor expression. |
| CXCL9 | 1.68 | Y | Y | Ligand for Cxcr3 receptor, activated by TLR ligands and pro-inflammatory cytokines; appears to regulate T cell migration |
| Egr2 | 1.96 | Y | Transcription factor; Alt priming gene | |
| EMR1 | 1.81 | Y | Y | Member of adhesion GPCR receptors; required to activate CD8+ regulatory T cells |
| FAM105A | 2.08 | Y | Y | |
| FCER1G | 1.74 | Y | Y | High affinity Fc epsilon receptor; binds TREM2; involved in response to apoptotic debris, immune complexes through C1q complex |
| FCGR2B | 2.89 | Y | Y | Fc receptor, IgG, low affinity; binds Cxcl7 (CD32B); inhibitory |
| FCGR3A | 1.52 | Y | Y | Aka CD16a; similar to FCGR2B |
| FCRLS | 2.78 | Y | Fc immunoglobulin receptor; part of TGFb1 microglial signature response | |
| GOLM1 | 1.53 | Y | Assists transport of cargo through Golgi apparatus; AD risk gene | |
| IGF1 | 0.65 | Y | Neurotrophic factor; increased by IL4/MCSF; M2 phenotype and Alt priming gene | |
| IGFBP6 | 1.53 | Y | Y | Binds IGF’s and modulates their growth factor effects |
| ITGB2 | 1.73 | Y | Y | CD18; integrin beta chain beta 2; involved in leukocyte adhesion |
| LGALS3 | 2.44 | Y | Galectin family; inflammatory factor (MAC2); microglial marker; Alt priming gene | |
| PTPRC | 1.84 | Y | Y | Protein tyrosine phosphatase; aka CD45; enriched in microglia; opposes microglial activation |
| PYCARD | 1.50 | Y | Y | Mediator of apoptosis and inflammation; adapter for inflammasome assembly |
| TLR7 | 1.84 | Y | Y | TLR (nucleotide sensing); signals via MyD88 pathway; can modulate other TLR’s |
| TMEM173 | 1.52 | Y | Y | Facilitates innate immune signaling; promotes expression of IFN-alpha and IFN-beta; |
| TREM2 | 1.74 | Y | Forms signaling complex with TYROBP; M2 state and sensome gene; promotes microglial expansion; up-regulated by IL4; critical for normal phagocytosis | |
| TYROBP | 1.82 | Y | Y | Forms signaling complex with TREM2; activates microglia; required for synaptic pruning |
The annotated differentially expressed gene set (353) was compared to previously published consensus genes specific for microglia. Those relevant to establishment of neuropathic pain are indicated