Biology subjects

Wendt, T. S.

Publications and source records attributed to Wendt, T. S..

3 recordsLinked to original sources

bioRxiv2023

OxLDL/LOX-1 Mediated Sex, Age, and Cell Dependent Alterations in Mouse Thoracic Aortic Vascular Reactivity

Elevated oxidized low-density lipoprotein (oxLDL) is a risk factor and component that worsens cardiovascular disease states. OxLDL can elicit its detrimental action, via lectin-like oxLDL receptor 1 (LOX-1) and has been shown to disrupt vascular function. In this study, we determined whether oxLDL, via LOX-1, alters aortic vascular reactivity and determined if sex differences exist. Thoracic aortic endothelium-intact or -denuded ring segments were isolated from intact C57BL/6J female and male mice and incubated with oxLDL ex vivo (50ug/dL; 2h). Using wire myography, cumulative concentration-response curves to phenylephrine (PE) were generated to determine contractile responses. From these curves, the EC50 was determined and used to contract rings to assess acetylcholine (ACh) dependent relaxation. Calculated aortic stiffness and remodeling, as well as mRNA expression of vasoactive and pro-inflammatory mediators were assessed. BI-0115 (10M; selective LOX-1 inhibitor) was used to determine LOX-1 dependence. We observed differential sex, age, endothelial cell, and LOX-1 dependent alterations to the efficacy of PE-induced contractile responses and ACh-mediated vasorelaxation in the thoracic aortic rings following oxLDL exposure. Additionally, we observed a distinct sex and age effect on thoracic aortic stiffness following exposure to oxLDL. There was also a sex effect on calculated vessel diameter, as well as an age effect on oxLDL-mediated inward remodeling that was LOX-1 dependent. Thus, LOX-1 inhibition and the resulting attenuation of oxLDL/endothelial-mediated alterations in aortic function suggests that there are differential sex differences in the role of oxLDL/LOX-1 in the thoracic aorta of male and female mice. NEW & NOTEWORTHYWe investigated the effects of oxidized low-density lipoprotein (oxLDL) via the LOX-1 receptor on murine thoracic aortic vasoreactivity, stiffness, and remodeling across age and sex. Acute exposure to oxLDL led to altered vasoreactivity, endothelial dysfunction, and changes in aortic stiffness and remodeling. These effects were in-part age, sex, endothelial, and LOX-1 dependent. This study reveals potential complex interactions in oxLDL/LOX-1-mediated vascular responses that could serve as potential therapeutic intervention for vascular diseases such as atherosclerosis. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/556764v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1bffb67org.highwire.dtl.DTLVardef@1122c31org.highwire.dtl.DTLVardef@1352d9org.highwire.dtl.DTLVardef@a44880_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2023

Selective S1PR1 activation improves brain infarction, neurological outcome, and cerebrovascular endothelial health following experimental ischemic injury

Sphingosine-1-phosphate receptor 1 (S1PR1) is highly expressed in endothelial cells and receptor activation plays an important role in mediating endothelial function and health, thus showing promise as a pharmacologic target for acute ischemic stroke (AIS) treatment. Here, we examined the effect of a selective S1PR1 ligand, RP101075, on infarct volume and neurological outcome in adult male mice subjected to transient middle cerebral artery occlusion (tMCAO). Concomitantly, we examined S1PR1 expression profile in the ischemic mouse brain, as well as S1PR1 expression and impact of receptor activation on human brain microvascular endothelial cell (HBMEC) proliferation and survival following hypoxia plus glucose deprivation (HGD). We observed that RP101075 administration at onset of reperfusion reduced infarct volume and lessened neurological deficits in tMCAO mice and these responses were S1PR1 dependent. Additionally, we observed that tMCAO increased brain S1PR1 protein levels and flow cytometry revealed increases in S1PR1 levels are greatest in brain endothelial cells compared to other brain cell types (astrocyte, neuron, microglia). In cultured HBMECs, RP101075 increased cell proliferation and ozanimod, parent compound of RP1010175, increased live cell count during HGD; this response was S1PR1 dependent. In conclusion, S1PR1 activation improves neuroprotection/outcome post-stroke and preserves brain endothelial cell survival following ischemia-like injury.

neuroscience↗

bioRxiv2023

Ozanimod Attenuates Human Cerebrovascular Endothelial Derived MMP-9 Activity and Preserves Barrier Properties Following In Vitro Acute Ischemic Injury

Endothelial integrity is critical in mitigating a vicious cascade of secondary injuries following acute ischemic stroke (AIS). Matrix metalloproteinase-9 (MMP-9), a contributor to endothelial integrity loss, is elevated during stroke and is associated with worsened stroke outcome. We investigated the FDA approved selective sphingosine-1-phosphate receptor 1 (S1PR1) ligand, ozanimod, on the regulation/activity of MMP-9 as well as endothelial barrier components (PECAM-1, claudin-5, and ZO-1) in human brain microvascular endothelial cells (HBMECs) following hypoxia plus glucose deprivation (HGD). We previously reported that S1PR1 activation improves HBMEC integrity; however, specific mechanisms underlying S1PR1 involvement in barrier integrity have not been clearly elucidated. We hypothesized that ozanimod would attenuate an HGD-induced increase in MMP-9 activity which would concomitantly attenuate the loss of integral barrier components. Male HBMECs were treated with ozanimod (0.5nM) or vehicle and exposed to 3h normoxia (21% O2) or HGD (1% O2). Immunoblotting, zymography, qRT-PCR, and immunocytochemical labeling techniques assessed processes related to MMP-9 and barrier markers. We observed that HGD acutely increased MMP-9 activity and reduced claudin-5 and PECAM-1 levels, and ozanimod attenuated these responses. In situ analysis via PROSPER, suggested that attenuation of MMP-9 activity may be a primary factor in maintaining these integral barrier proteins. We also observed that HGD increased intracellular mechanisms associated with augmented MMP-9 activation, however ozanimod had no effect on these targeted factors. Thus, we conclude that ozanimod has the potential to attenuate HGD mediated decreases in HBMEC integrity in part by decreasing MMP-9 activity as well as preserving barrier properties. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=128 SRC="FIGDIR/small/526738v2_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@b4df43org.highwire.dtl.DTLVardef@addf76org.highwire.dtl.DTLVardef@129e86forg.highwire.dtl.DTLVardef@5ae8a0_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗