bims-mideyd 2024-05-12 papers

Issue of 2024‒05‒12
three papers selected by
Rajalekshmy “Raji” Shyam, Indiana University Bloomington

Exp Eye Res. 2024 May 08. pii: S0014-4835(24)00140-4. [Epub ahead of print] 109919

Human amniotic mesenchymal stem cells-derived conditioned medium and exosomes alleviate oxidative stress-induced retinal degeneration by activating PI3K/Akt/FoxO3 pathway.

Zhe-Qing Peng, Xiao-Hui Guan, Zhen-Ping Yu, Jie Wu, Xin-Hao Han, Ming-Hui Li, Xin-Hui Qu, Zhi-Ping Chen, Xiao-Jian Han, Xiao-Yu Wang.

Age-related macular degeneration (AMD) is the leading cause of vision loss among the elderly, which is primarily attributed to oxidative stress-induced damage to the retinal pigment epithelium (RPE). Human amniotic mesenchymal stem cells (hAMSC) were considered to be one of the most promising stem cells for clinical application due to their low immunogenicity, tissue repair ability, pluripotent potential and potent paracrine effects. The conditional medium (hAMSC-CM) and exosomes (hAMSC-exo) derived from hAMSC, as mediators of intercellular communication, play an important role in the treatment of retinal diseases, but their effect and mechanism on oxidative stress-induced retinal degeneration are not explored. Here, we reported that hAMSC-CM alleviated H2O2-induced ARPE-19 cell death through inhibiting mitochondrial-mediated apoptosis pathway in vitro. The overproduction of reactive oxygen species (ROS), alteration in mitochondrial morphology, loss of mitochondrial membrane potential and elevation of Bax/Bcl2 ratio in ARPE-19 cells under oxidative stress were efficiently reversed by hAMSC-CM. Moreover, it was found that hAMSC-CM protected cells against oxidative injury via PI3K/Akt/FoxO3 signaling. Intriguingly, exosome inhibitor GW4869 alleviated the inhibitory effect of hAMSC-CM on H2O2-induced decrease in cell viability of ARPE-19 cells. We further demonstrated that hAMSC-exo exerted the similar protective effect on ARPE-19 cells against oxidative damage as hAMSC-CM. Additionally, both hAMSC-CM and hAMSC-exo ameliorated sodium iodate-induced deterioration of RPE and retinal damage in vivo. These results first indicate that hAMSC-CM and hAMSC-exo protect RPE cells from oxidative damage by regulating PI3K/Akt/FoxO3 pathway, suggesting hAMSC-CM and hAMSC-exo will be a promising cell-free therapy for the treatment of AMD in the future.

Keywords: PI3K/Akt/FoxO3 pathway; age-related macular degeneration; exosomes; human amniotic mesenchymal stem cells; intrinsic apoptosis; oxidative stress

DOI: https://doi.org/10.1016/j.exer.2024.109919

Mol Biol Rep. 2024 May 10. 51(1): 637

Vitamin C alleviates hyperglycemic stress in retinal pigment epithelial cells.

Hamid Alahmari, Chia-Chun Liu, Elizabeth Rubin, Venice Y Lin, Paul Rodriguez, Kun-Che Chang.

BACKGROUND: Retinal pigment epithelial cells (RPECs) are a type of retinal cells that structurally and physiologically support photoreceptors. However, hyperglycemia has been shown to play a critical role in the progression of diabetic retinopathy (DR), which is one of the leading causes of vision impairment. In the diabetic eye, the high glucose environment damages RPECs via the induction of oxidative stress, leading to the release of excess reactive oxygen species (ROS) and triggering apoptosis. In this study, we aim to investigate the antioxidant mechanism of Vitamin C in reducing hyperglycemia-induced stress and whether this mechanism can preserve the function of RPECs.METHODS AND RESULTS: ARPE-19 cells were treated with high glucose in the presence or absence of Vitamin C. Cell viability was measured by MTT assay. Cleaved poly ADP-ribose polymerase (PARP) was used to identify apoptosis in the cells. ROS were detected by the DCFH-DA reaction. The accumulation of sorbitol in the aldose reductase (AR) polyol pathway was determined using the sorbitol detection assay. Primary mouse RPECs were isolated from adult mice and identified by Rpe65 expression. The mitochondrial damage was measured by mitochondrial membrane depolarization. Our results showed that high glucose conditions reduce cell viability in RPECs while Vitamin C can restore cell viability, compared to the vehicle treatment. We also demonstrated that Vitamin C reduces hyperglycemia-induced ROS production and prevents cell apoptosis in RPECs in an AR-independent pathway.
CONCLUSIONS: These results suggest that Vitamin C is not only a nutritional necessity but also an adjuvant that can be combined with AR inhibitors for alleviating hyperglycemic stress in RPECs.

Keywords: Apoptosis; Hyperglycemia; ROS; Retinal pigment epithelial cell; Vitamin C

DOI: https://doi.org/10.1007/s11033-024-09595-2

Elife. 2024 May 09. pii: RP92510. [Epub ahead of print]12

Pigmentation level of human iPSC-derived RPE does not indicate a specific gene expression profile.

Yoko Nakai-Futatsugi, Jianshi Jin, Taisaku Ogawa, Noriko Sakai, Akiko Maeda, Ken-Ichi Hironaka, Masakazu Fukuda, Hiroki Danno, Yuji Tanaka, Seiji Hori, Katsuyuki Shiroguchi, Masayo Takahashi.

Retinal pigment epithelium (RPE) cells show heterogeneous levels of pigmentation when cultured in vitro. To know whether their color in appearance is correlated with the function of the RPE, we analyzed the color intensities of human-induced pluripotent stem cell-derived RPE cells (iPSC-RPE) together with the gene expression profile at the single-cell level. For this purpose, we utilized our recent invention, Automated Live imaging and cell Picking System (ALPS), which enabled photographing each cell before RNA-sequencing analysis to profile the gene expression of each cell. While our iPSC-RPE were categorized into four clusters by gene expression, the color intensity of iPSC-RPE did not project any specific gene expression profiles. We reasoned this by less correlation between the actual color and the gene expressions that directly define the level of pigmentation, from which we hypothesized the color of RPE cells may be a temporal condition not strongly indicating the functional characteristics of the RPE.

Keywords: automated Live imaging; cell Picking System (ALPS); cell biology; heterogeneity; human; retinal pigment epithelium (RPE) cell; single-cell RNA sequencing

DOI: https://doi.org/10.7554/eLife.92510