Biology subjects

Chrenek, M.

Publications and source records attributed to Chrenek, M..

3 recordsLinked to original sources

bioRxiv2026

Dietary serine protects the retinal pigmented epithelium by blunting reactive oxygen species in dry age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive complex eye disease and one of the leading causes of blindness. AMD progression is marked by molecular changes in the retinal pigmented epithelium (RPE) which include increased reactive oxygen species (ROS) accumulation, mitochondrial dysfunction - eventually leading to dysfunctional RPE. Mitophagy regulator, Pink1, is reduced in the RPE of AMD patients and Pink1 loss leads to a shift from mitochondrial respiration to glycolysis. Serine is a non-essential amino acid which is de novo synthesized from glycolytic intermediate 3-PG via the rate limiting enzyme PHGDH. Serine is tightly integrated into anabolic processes like glutathione (GSH) cycling, maintaining NADH/NADPH pools leading to changes in AMPK signaling. Here, we show that Pink1 loss leads to a reduction in PHGDH and serine levels in the RPE leading to impaired mitochondrial structure and function, increased ROS mediated damage, increased inflammation, and hampered retinal function. Serine supplementation rescued ROS accumulation, balanced GSH abundance, and increased retinal function. Overall, our study highlights the potential of dietary serine in ROS management in AMD.

molecular biology↗

bioRxiv2026

Microtubule stability modulates Schlemm's canal cell mechanobiology and outflow facility in glaucoma

PurposeThe inner wall of Schlemms canal (SC) is a mechanosensitive endothelial monolayer that provides resistance to conventional aqueous humor drainage, a process dependent on pore formation. This study examined how microtubule (MT) stability affects SC cell mechanobiology, transcellular pore formation, and aqueous humor outflow dynamics. MethodsMT stability in cultured SC cells from normal and glaucomatous human donors was manipulated pharmacologically. Changes in MT acetylation, phosphorylated myosin light chain, and F-actin were assessed by immunofluorescence and immunoblotting. GEF-H1 was knocked down using siRNA. Cellular stiffness was measured by atomic force microscopy. Transcellular pore formation was quantified using an established pore formation assay. Outflow facility was measured in enucleated mouse eyes using the iPerfusion system. ResultsMT stabilization in normal SC cells decreased actomyosin contractility and cellular stiffness, whereas MT destabilization increased contractility and stiffness; these effects involved the MT-associated Rho guanine nucleotide exchange factor GEF-H1. MT stability was also mechano-responsive to substrate stiffness. Furthermore, SC cells derived from glaucomatous donors exhibited reduced MT stability compared with normal SC cells. MT stabilization increased transcellular pore formation in both normal and glaucomatous SC cells. In ex vivo mouse eyes, paclitaxel perfusion to stabilize MTs significantly increased outflow facility relative to contralateral control eyes. ConclusionsOur data suggest that MT stability influences SC cell contractility, stiffness, and transcellular pore formation and can alter aqueous humor outflow facility. These findings identify MT-dependent cytoskeletal remodeling as an important contributor to the biomechanics of the conventional outflow pathway and suggest that MT-associated pathways may represent potential targets for improving outflow function in glaucoma.

cell biology↗

bioRxiv2024

Age-related RPE Changes in Wildtype C57BL/6J Mice Between 2 and 32 Months

PurposeThis study provides a systematic evaluation of age-related changes in RPE cell structure and function using a morphometric approach. We aim to better capture nuanced predictive changes in cell heterogeneity that reflect loss of RPE integrity during normal aging. Using C57BL6/J mice ranging from P60-P730, we sought to evaluate how regional changes in RPE shape reflect incremental losses in RPE cell function with advancing age. We hypothesize that tracking global morphological changes in RPE is predictive of functional defects over time. MethodsWe tested three groups of C57BL/6J mice (young: P60-180; Middle-aged: P365-729; aged: 730+) for function and structural defects using electroretinograms, immunofluorescence, and phagocytosis assays. ResultsThe largest changes in RPE morphology were evident between the young and aged groups, while the middle-aged group exhibited smaller but notable region-specific differences. We observed a 1.9-fold increase in cytoplasmic alpha-catenin expression specifically in the central-medial region of the eye between the young and aged group. There was an 8-fold increase in subretinal, IBA-1-positive immune cell recruitment and a significant decrease in visual function in aged mice compared to young mice. Functional defects in the RPE corroborated by changes in RPE phagocytotic capacity. ConclusionsThe marked increase of cytoplasmic alpha-catenin expression and subretinal immune cell deposition, and decreased visual output coincide with regional changes in RPE cell morphometrics when stratified by age. These cumulative changes in the RPE morphology showed predictive regional patterns of stress associated with loss of RPE integrity.

cell biology↗