Biology subjects

Gu, S. M.

Publications and source records attributed to Gu, S. M..

3 recordsLinked to original sources

bioRxiv2026

DTCAMD, a disease-associated truncated form of CRYAB in neovascular age-related macular degeneration: a potential driver of subretinal fibrosis

Abstract Purpose: Subretinal fibrosis causes irreversible vision loss in neovascular age-related macular degeneration (nAMD) and remains poorly controlled by anti-vascular endothelial growth factor (VEGF) therapy. We investigated the role of B-crystallin (CRYAB) in angiogenic and fibrotic pathology and evaluated disease-associated CRYAB truncation as a therapeutic target. Methods: Aqueous humor from patients with nAMD was analyzed by quantitative proteomics and receiver operating characteristic (ROC) analysis. CRYAB function was assessed using knockout and knockdown approaches in a choroidal neovascularization (CNV) mouse model. CRYAB truncation and associated proteins were examined by immunoblotting, co-immunoprecipitation, and liquid chromatography-tandem mass spectrometry (LC-MS/MS). C-terminal truncation was further examined in mouse retinal tissue using antibodies generated against full-length CRYAB and its C-terminal region. Primary human retinal pigment epithelial (hRPE)-THP-1 co-cultures were used to examine CRYAB truncation under fibrosis-associated conditions. Pharmacological effects were tested using ({+/-})-threo-3-methylglutamic acid (T3MG) and 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF). Results: CRYAB was upregulated in the aqueous humor of patients with nAMD. Higher CRYAB levels were associated with persistent lesions after initial anti-VEGF treatment. CRYAB knockout or knockdown reduced CNV pathology and decreased VEGFA and -smooth muscle actin (SMA) expression, without a significant substrain effect between C57BL/6N and C57BL/6J mice. A Ser45-phosphorylated truncated CRYAB species was detected in mouse laser-induced CNV model. We termed this species disease-associated truncated CRYAB in AMD (DTCAMD). Peptide mapping showed reproducible loss of distal C-terminal peptide coverage in truncated CRYAB. Consistent with this finding, C-terminal antibody recognition was reduced in CNV lesions. In hRPE-THP-1 co-cultures, DTCAMD accumulated with increased SMA expression. Proteomic analysis identified Prss1 as a candidate CRYAB-associated serine protease linked to truncation under CNV conditions. T3MG and AEBSF reduced DTCAMD-associated signals and CNV pathology. Conclusions: CRYAB contributes to angiogenic and fibrotic pathology in CNV. Disease-associated CRYAB truncation, particularly Ser45-phosphorylated DTCAMD, represents a potential therapeutic target for fibrotic remodeling in nAMD.

pathology↗

bioRxiv2026

Acute head shaking precedes chronic corpus callosum deficits during repeated cocaine exposure in common marmosets

Background: Stimulant exposure can induce acute stereotyped behaviors and chronic alterations in brain connectivity and white matter integrity. However, the temporal sequence and molecular changes linking these cocaine-induced phenotypes remain unclear. Methods: We combined LabGym-based behavioral analysis, longitudinal brain imaging, and cross-species molecular analysis in 11 common marmosets (Callithrix jacchus; seven male, four female): four underwent behavioral and imaging studies, six provided molecular data, and one provided immunohistochemical data. Male Cryab knockout and wild-type mice underwent functional studies. Results: Acute cocaine (5 mg/kg, intraperitoneally) induced rapid, repetitive lateral head movements, defined as head shaking. After 1 and 10 months of repeated exposure, resting-state functional connectivity was altered in sensory, parietal, prefrontal, motor, and hippocampal regions. Changes were detected at 1 month, whereas diffusion tensor imaging showed reduced fractional anisotropy and axial diffusivity in the corpus callosum splenium at 10 months, with no significant genu changes. Cross-species transcriptomic and proteomic comparison identified DPYSL2 and DNM3 as shared axon-associated molecules. Western blotting showed reduced DPYSL2 in brain tissue from cocaine-treated marmosets. CRYAB localized to O4-positive callosal oligodendrocytes and increased following chronic cocaine exposure. Cryab knockout mice had reduced corpus callosum thickness, increased forced-swim immobility, and reduced open-field distance traveled, supporting a role for CRYAB in corpus callosum integrity and depression-related behavior. Conclusions: These findings show that acute cocaine-induced stereotyped head shaking precedes functional connectivity changes and later corpus callosum deficits. Reduced DPYSL2 may be associated with axonal dysfunction, whereas increased CRYAB may represent a response to cocaine-induced white matter stress.

pharmacology and toxicology↗

bioRxiv2026

Restoration of circulating 2-arachidonoylglycerol levels attenuates cocaine self-administration through endocannabinoid-dopamine interactions in common marmosets

To date, no pharmacotherapy has been approved for cocaine use disorder. Endocannabinoid signaling is closely related to dopamine-dependent reinforcement and may regulate cocaine-related behaviors. In this study, we used common marmosets (Callithrix jacchus) to investigate whether 2-arachidonoylglycerol (2-AG), an endogenous cannabinoid lipid, reduces cocaine reinforcement in a non-restraint oral self-administration model. Marmosets performed oral cocaine self-administration under a fixed-ratio 1 schedule, and cocaine intake was confirmed using plasma benzoylecgonine detection. Dopamine transporter (DAT)-related positron emission tomography (PET) signal, DAT and G protein-coupled receptor 55 (GPR55)-associated fluorescent signals, GPR55/DAT immunofluorescence, and synaptosomal dopamine responses were assessed using 18F-N-(3-fluoropropyl)-2{beta}-carboxymethoxy-3{beta}-(4-iodophenyl) nortropane (18F-FP-CIT) PET imaging, ex vivo fluorescent ligand imaging, confocal microscopy, and dopamine quantification. Marmosets acquired oral cocaine self-administration with preferential active lever responding. Repeated cocaine self-administration reduced striatal DAT-related 18F-FP-CIT PET signal in vivo. In striatal slices, cocaine decreased fluorescent false neurotransmitter (FFN102)-associated DAT signal and increased T1117-associated GPR55 signal. Systemic 2-AG pretreatment reduced cocaine self-administration while restoring diminished circulating 2-AG levels. GPR55 and DAT immunofluorescent signals were colocalized in marmoset brain sections, and 2-AG enhanced cocaine-induced dopamine elevation in synaptosomal preparations. Taken together, these findings suggest that 2-AG attenuates cocaine-taking behavior and may be associated with GPR55/DAT-related dopaminergic responses in common marmosets.

pharmacology and toxicology↗