Biology subjects

Gonzales, R.

Publications and source records attributed to Gonzales, R..

4 recordsLinked to original sources

bioRxiv2026

Clinical Relevant Immunosuppressive Drugs Differentially Modulate Axonal Outgrowth from Human Stem Cell Derived Neurons

Neural stem cell (NSC) transplantation is a promising strategy for repairing the injured spinal cord, but transplanted cells typically require immunosuppressive therapy to prevent rejection--even for induced pluripotent stem cell (iPSC)-derived autologous grafts. However, the effects of immunosuppressive drugs on neurite outgrowth and axonal regeneration-- processes critical for neural circuit reconstruction--have not been fully characterized. In this study, we tested nine clinically relevant immunosuppressants on human iPSC-derived neurons and primary human spinal cord NSCs in vitro at concentrations approximating clinical exposure levels. The drug panel included FK-506 (tacrolimus), cyclosporine A (CsA), rapamycin, belatacept (Nulojix), etanercept (Enbrel), mycophenolate mofetil (CellCept), cyclophosphamide (Cytoxan), prednisone, and azathioprine (Imuran). Neurite outgrowth was quantified via automated high-content imaging. Multiple agents, including CsA, Imuran, Nulojix, and CellCept, induced significant reductions in neurite outgrowth in a cell type- and dose-dependent manner, with CsA producing the most robust and consistent inhibition across both cell lines. In contrast, FK-506 showed no significant effect on neurite extension at clinically relevant concentrations. Consistent with the in vitro results, human neural progenitor cell grafts in a rodent spinal cord injury model exhibited significantly reduced graft-derived axon extension in the host spinal cord when hosts were treated with CsA rather than FK-506. These findings demonstrate that immunosuppressant choice can profoundly influence neural graft integration and axonal regeneration. Our study underscores the importance of preclinical evaluation of immunosuppressive regimens and suggests that selecting agents such as FK-506 over CsA may improve outcomes in future stem cell-based therapeutic trials for spinal cord injury and related disorders of the central nervous system. HighlightsO_LICyclosporine A inhibits axon outgrowth in human neurons in vitro C_LIO_LIFK-506 preserves neurite extension across stem cell-derived neuron types C_LIO_LIAxon outgrowth is reduced in vivo with CsA but not FK-506 C_LIO_LIImmunosuppressant selection critically affects neural graft integration C_LIO_LIFK-506 may be preferable to CsA for SCI cell transplantation protocols C_LI

neuroscience↗

bioRxiv2023

LOX-1 and MMP-9 inhibition attenuates the detrimental effects of delayed rt-PA therapy and improves outcomes after acute ischemic stroke

BackgroundAcute ischemic stroke triggers endothelial activation that disrupts vascular integrity and increases hemorrhagic transformation leading to worsened stroke outcomes. Recombinant-tissue plasminogen activator (rt-PA) is an effective treatment; however, its use is limited due to a restricted time window and high risk for hemorrhagic transformation, which in part may involve activation of metalloproteinases (MMPs) mediated through lectin-like oxidized LDL receptor 1 (LOX-1). This studys overall aim was to evaluate the therapeutic potential of novel MMP-9 and LOX-1 inhibitors in combination with rt-PA to improve stroke outcomes. MethodsThromboembolic rat stroke model was utilized to investigate the impact of rt-PA delivered 4h post-stroke onset as well as selective LOX-1 (BI-0115) and/or MMP-9 (JNJ0966) inhibitors given prior to rt-PA administration. Infarct size, perfusion, and hemorrhagic transformation were evaluated by MRI. Neurological function was assessed using sensorimotor functioning testing. Using an in vitro, human brain microvascular endothelial cell (HBMEC) model, cells were exposed to hypoxia plus glucose deprivation (3h)/reperfusion (12h) (HGD/R) and treated with rt-PA {+/-} an MMP-9 and LOX-1 inhibition cocktail. MMP-9 activity was determined with zymography, and endothelial barrier marker gene expression and LOX-1 levels were evaluated via qRT-PCR and western blot respectively. ResultsRt-PA treatment increased edema, hemorrhage, and worsened neurological outcomes post stroke. LOX-1 inhibition significantly improved neurological function and reduced edema after delayed rt-PA treatment. Hemorrhagic transformation, edema, and increased MMP-9 activity were attenuated by the MMP-9 inhibitor. Stroke induced increases in cerebrovascular LOX-1 expression correlated with increased MMP-9 activity and elevated activity correlated with increased edema, infarct volume, and decreased neurological function. In cultured HBMECs, LOX-1/MMP-9 inhibition differentially attenuated rt-PA-mediated increases in endothelial derived MMP-9 levels and activity, inflammation, and activation following HGD/R. ConclusionHere, we conclude that MMP-9/LOX-1 inhibition attenuates negative aspects of delayed rt-PA therapy leading to improved neurological function.

neuroscience↗

bioRxiv2022

Activity of the manganese efflux transporter SLC30A10 in dopaminergic but not GABAergic neurons protects against neurotoxicity

Metals such as copper, iron, and manganese (Mn) are essential for life, but induce neurotoxicity at elevated levels. Yet, the neuronal mechanisms of metal-induced neurological disease are largely unclear. A primary limitation has been an inability to selectively alter metal levels in specific neurons, so that the role of the targeted neurons in disease biology can be isolated. Here, we show that neuron-specific depletion of metal efflux transporters provides the feasibility to overcome this limitation by focusing on Mn, which accumulates in the basal ganglia and induces motor disease, and the Mn-specific efflux transporter SLC30A10. Pan-neuronal/glial Slc30a10 knockout mice exhibited increased basal ganglia Mn levels and hypolocomotor deficits in early-life (pre-adulthood), which were exacerbated by Mn exposure. The locomotor deficits of the pan-neuronal/glial strain was associated with a reduction in evoked striatal dopamine release without dopaminergic (DAergic) neurodegeneration or changes in striatal tissue dopamine levels. Furthermore, DAergic-specific, but not GABAergic-specific, Slc30a10 knockout mice recapitulated the hypolocomotor phenotype of the pan-neuronal/glial knockouts in early-life although Mn levels were elevated in the targeted basal ganglia regions of both the neuron-specific strains. Put together, our results imply that (1) activity of SLC30A10 in DAergic neurons is necessary to protect against early-life Mn neurotoxicity; (2) increasing Mn levels in DAergic neurons is sufficient to induce early-life motor disease, suggesting that Mn targets DAergic neurons in the early-life period to induce motor deficits; and (3) neuron-specific knockout of metal efflux transporters may be a widely applicable strategy to elucidate mechanisms of metal-induced neurotoxicity.

neuroscience↗

bioRxiv2022

Chronic Cognitive and Cerebrovascular Function Following Mild Traumatic Brain Injury in Rats

Severe traumatic brain injury results in cognitive dysfunction in part due to vascular perturbations. In contrast, the long-term vasculo-cognitive pathophysiology of mild TBI (mTBI) remains unknown. We evaluated mTBI effects on chronic cognitive and cerebrovascular function and assessed their interrelationships. Sprague-Dawley rats received midline fluid percussion injury (N=20) or sham (N=21). Cognitive function was assessed (3- and 6-month novel object recognition (NOR), novel object location (NOL) and temporal order object recognition (TOR)). 6-month cerebral blood flow (CBF) and blood volume (CBV) using contrast MRI and ex vivo pial artery endothelial and smooth muscle-dependent function were measured. mTBI rats showed impaired NOR, with similar (non-significant) trends in NOL/TOR. Regional CBF and CBV were similar in sham and mTBI. NOR correlated with CBF in lateral hippocampus, medial hippocampus and primary somatosensory barrel cortex while inversely correlating with arterial smooth muscle-dependent dilation. 6-month baseline endothelial and smooth muscle-dependent arterial function were similar among mTBI and sham, but post-angiotensin II stimulation, mTBI showed no change in smooth muscle-dependent dilation from baseline response, unlike the reduction in sham. mTBI led to chronic cognitive dysfunction and altered angiotensin II-stimulated smooth muscle-dependent vasoreactivity, a paradigm that could advance understanding of the long-term sequelae of human mild TBI.

neuroscience↗