Dataset Information

Age-associated Tissue Organization Shifts Retinal Pigmented Epithelium Actomyosin Plasticity in Phagocytosis

ABSTRACT: Mechanical homeostasis in healthy tissues relies on a dynamic balance of mechanical properties essential for maintaining tissue integrity and function. Over time, this integrity decays due to structural reorganization from extracellular remodelling or an imbalance of cell death and proliferation. This is particularly challenging in postmitotic tissues such as the retina, where lack of proliferation requires age-dependent structural adaptation. The retinal pigment epithelium exemplifies this adaptation, compensating for apoptotic events through morphological reconfiguration and cytoskeletal remodelling. To explore the connection between age-related structural changes and mechanical homeostasis, we developed an in vitro model simulating cell density reduction observed in the human retinal pigmented epithelium during ageing. This model is characterized by reduced cell height, shortened apical microvilli, and alterations in the actin cytoskeleton. The resulting age-associated phenotype leads to significant biomechanical changes, including tissue stiffening, enhanced junctional contractility, and apical cell cortex remodelling. Transcriptional profiling revealed notable shifts in actin-associated gene expression, indicating reduced plasticity when remodelling is necessary for phagocytosis of photoreceptor outer segments. Structurally aged monolayers exhibit changes in phagocytic activity that mirror those seen in aged individuals. Additionally, we observed an impaired capacity for apico-lateral remodelling while internalizing photoreceptor outer segments. This altered activity can be partially corrected by regulating actin network remodelling capacity with inhibitors targeting the actin nucleators Arp2/3 and formins. Overall, our findings suggest that age-related structural changes in the postmitotic outer retina shift its mechanical homeostasis, impacting physiological functions that are crucial for healthy vision.

ORGANISM(S): Homo sapiens

PROVIDER: GSE297557 | GEO | 2025/06/20

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other
	GSE297557_salmon.merged.gene_counts.csv.gz	Csv

Items per page:

1 - 2 of 2

Similar Datasets

Project description:Methods: Profiles of individual human retinal organoids (HRO) at 150, 200 and 250 days of development days were treated for 10 days with HBEGF and TNF, and compared to solvent controls (CTRL). N=6 HROs per timepoint and variable. Single-end sequencing with 30 Mio reads per sample was performed at a length of 75 bases on HiSeq2500 (Illumina). The sequence reads that passed quality filters were analyzed at the transcripts level. Results: Our data independently confirms that this protocol provides HROs with macular-like characteristics and shows low baseline variabilities for rods, cones and Müller glia. These features might be key for disease modeling, since most animal models lack a macula, and most other organoid protocols have low cone cell numbers. We found a significant reduction in the number of rod and cone photoreceptor cells after 10 days after HBEGF-TNF (HT) treatment. Specifically, some photoreceptors show pathologic changes, and some are apically displaced, with their nuclei protruding into or passing out of the retina. Histopathologic changes indicate photoreceptor extrusion of viable or dying cones and rods as a pathomechanism. Notably, photoreceptor displacement through the apical retinal border, and thus ectopy in the region of photoreceptor inner and outer segments, has been described in patients and animal models. In controls, photoreceptors were highly ordered, interspersed and interconnected with each other and with Müller glia processes, and these cell connections make up the outer limiting membrane. Upon HT, glial processes expanded in size, extended laterally along the retinal circumference, and replaced or covered photoreceptors over large areas – forming a seal-like glial scar. Taken together, HT induces photoreceptor degeneration via cell extrusion in conjunction with reactive gliosis, glial proliferation, retinal thickening/dyslamination, and glial seal-like scar formation, which reproduces a complex outer retinal atrophy. Interestingly, our transcriptome data revealed distinct gene expression patterns supporting our histological phenotype, specifically, cone and rod degeneration, reactive gliosis, glial proliferation, and photoreceptor cell extrusion. Conclusions: We show that combined application of HBEGF and TNF, two neuropathology associated factors, is sufficient to induce a complex human retinal pathology. We discovered cone and rod cell extrusion as a pathomechanism for photoreceptor degeneration and a potential interrelationship with glial pathologies. Pharmacological inhibitor experiments support this, and PIEZO1 and MAPK signaling as untapped therapeutic targets, even for complex pathologies. Thus, our model provides mechanistic access to several pathologic processes as well as pathogenic functions of inflammation and biomechanics.

Project description:Aging is an independent risk factor for cardiovascular disease. Preventing age-induced arterial dysfunction and the associated risk of cardiovascular disease remains a signiﬁcant clinical challenge. Aerobic exercise, which induces a temporary increase in both blood flow and pressure in active tissue, has been shown to reduce macroscale arterial stiffening in humans. The purpose of this study was to investigate the effects of mechanical stimuli on improving aging pathophysiology of VSM cells isolated from soleus feed arteries (SFA). We hypothesized that exposure to external mechanical stimulation enhances formation of smooth muscle alpha-actin (SMα-actin) fibers and cell-matrix adhesions in aged VSM cells. Ex-vivo functional studies were used to assess myogenic contractility of VSM in isolated SFA from young (4 months) and old (24 months) Fischer 344 rats. These data indicated that pre-treatment of isolated aged SFA with a short-duration increase in intraluminal pressure rescued contractility. The mechanical stretch-induced remodeling of the cellular architecture was assessed in VSM cells isolated from young and old SFA. To dissect the mechanisms involved, the structural and functional properties of VSM cells were assessed by using mechanical stimulation combined with fluorescence confocal microscopy. Results showed that aged VSM cells respond faster than young cells to 2D biaxial cyclic stretch by increasing actin stress fiber formation and vinculin recruitment at cell-matrix adhesions. In addition, hydrostatic pressure treatment applied to aged VSM cells plated on stiffer substrates restores actin fibers and integrin β1 recruitment. Taken together, these findings suggest that discrete VSM cell mechanical properties and their ability to adapt to external mechanical signals are key in restoring VSM contractility in aging. These results are significant because they provide a novel understanding of the mechanisms by which mechanical stimulation improves VSM contractility in aged resistance arteries. Our results provide new insights into the role of VSM in vascular aging and highlight a new direction for mitigating age-related effects via mechanical stimulation-induced VSM remodeling.

Dataset Information

Age-associated Tissue Organization Shifts Retinal Pigmented Epithelium Actomyosin Plasticity in Phagocytosis

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets