bims-kishpe 2024-12-29 papers

bims-kishpe

Biomed News

on HSP70 role in hypoxia and metabolism in ECs

Issue of 2024–12–29
sixteen papers selected by
Alia Ablieh, Universität Heidelberg

Epigenetic regulation of vascular smooth muscle cell phenotypes in atherosclerosis.
Pulmonary arterial hypertension with left to right shunts: When to treat and/or close?
YTHDF3-induced degradation of P4HA2 mRNA inhibits glycolysis in papillary thyroid cancer through Hippo signaling pathway.
Myocardial mRNA expression of interleukin-6 and hypoxia inducible factor-1α in neonates with congenital cardiac defects.
Impact of galectin-3 on neurotrophic factor expression by PCR array: potential implications for the human cornea.
Effects of Empagliflozin and Dapagliflozin in alleviating cardiac fibrosis through SIRT6-mediated oxidative stress reduction.
Integrated Profiling of Extracellular Vesicle microRNA Impact on Trabecular Meshwork mRNA Expression: Insights From Microarray Analysis.
SALL4 mediates SHP2 inhibition in myocardial fibroblasts through the DOT1L/H3K79me2 signaling pathway to promote the progression of myocardial infarction.
Evaluating the role of active TGF-β1 as inflammatory biomarker in Kashmiri (North-Indian) patients with systemic sclerosis: a case-control study.
Knockdown of BATF alleviates lung injury in septic neonates through transcriptional regulation of COTL1.
Molecular Pathophysiology of Chronic Thromboembolic Pulmonary Hypertension: A Clinical Update from a Basic Research Perspective.
N6-methyladenosine reader YTHDF2 in cell state transition and antitumor immunity.
Taurine mechanism in preventing retinal cell damage from acute ocular hypertension through GTPBP3 regulation.
Transcriptomic changes in retinal ganglion cell types associated with the disruption of cholinergic retinal waves.
Changes in MicroRNAs expression mediate molecular mechanism underlying the effect of MeJA on the biosynthesis of podophyllotoxin in Linum album cells.
PCNA and Rnh1 independently participate in the protection of mitochondrial genome against UV-induced mutagenesis in yeast cells.

Atherosclerosis. 2024 Dec 10. pii: S0021-9150(24)01515-6. [Epub ahead of print] 119085

Epigenetic regulation of vascular smooth muscle cell phenotypes in atherosclerosis.

Jordi Lambert, Helle F Jørgensen.

  Vascular smooth muscle cells (VSMCs) in adult arteries maintain substantial phenotypic plasticity, which allows for the reversible cell state changes that enable vascular remodelling and homeostasis. In atherosclerosis, VSMCs dedifferentiate in response to lipid accumulation and inflammation, resulting in loss of their characteristic contractile state. Recent studies showed that individual, pre-existing VSMCs expand clonally and can acquire many different phenotypes in atherosclerotic lesions. The changes in gene expression underlying this phenotypic diversity are mediated by epigenetic modifications which affect transcription factor access and thereby gene expression dynamics. Additionally, epigenetic mechanisms can maintain cellular memory, potentially facilitating reversion to the contractile state. While technological advances have provided some insight, a comprehensive understanding of how VSMC phenotypes are governed in disease remains elusive. Here we review current literature in light of novel insight from studies at single-cell resolution. We also discuss how lessons from epigenetic studies of cellular regulation in other fields could help in translating the potential of targeting VSMC phenotype conversion into novel therapies in cardiovascular disease.

Keywords:  Epigenetic; Vascular smooth muscle cells

DOI:  https://doi.org/10.1016/j.atherosclerosis.2024.119085
Int J Cardiol Congenit Heart Dis. 2024 Sep;17 100526

Pulmonary arterial hypertension with left to right shunts: When to treat and/or close?

Michele D'Alto, Emanuele Romeo, Paola Argiento, Andrea Vergara, Eleonora Caiazza, Antonio Orlando, Rosa Franzese, Giancarlo Scognamiglio, Berardo Sarubbi, Konstantinos Dimopoulos.

  Pulmonary arterial hypertension (PAH) is defined as increase in mean pulmonary arterial pressure and pulmonary vascular resistance (PVR). It can be associated with congenital heart disease (CHD) with the following subtypes: 1) uncorrected left-to-right (L-R) intracardiac shunt leading to overload of the pulmonary circulation and a progressive increase of PVR; 2) Eisenmenger syndrome, appearing when a large post-tricuspid shunt is left uncorrected and pulmonary vascular disease (PVD) is severe, so the shunt becomes bidirectional or right-to-left, causing cyanosis; 3) PAH after shunt closure, when PVR arises after a defect correction; and 4) PAH associated with small or coincidental defects. While the treatment of patients with Eisenmenger syndrome is well established, the treatment of patients with PAH in whom there is a L-R shunt (with no cyanosis) remains unclear and requires expertise. In such patients, correction of the defect may be contemplated if there is mild PVD and a significant L-R shunt. Others may benefit from a "treat and repair" strategy, which involves the use of PAH therapy to achieve a drop in PVR, with the aim of achieving operability criteria. Cardiac catheterization is at the center of the evaluation and follow-up of these patients, collecting "baseline" data and providing the opportunity to challenge the pulmonary circulation, manipulate the loading status, or temporarily occlude the defect. This article provides a detailed overview of the pathophysiology and treatment options for patients with PAH associated with a L-R congenital shunt, including current approaches to operability and the use of PAH therapies.

Keywords:  Congenital heart disease; Hemodynamics assessment; Intracardiac shunts; Pulmonary hypertension

DOI:  https://doi.org/10.1016/j.ijcchd.2024.100526
Int J Biol Macromol. 2024 Dec 24. pii: S0141-8130(24)09961-6. [Epub ahead of print] 139150

YTHDF3-induced degradation of P4HA2 mRNA inhibits glycolysis in papillary thyroid cancer through Hippo signaling pathway.

Ying Ding, Mengyuan Liu, Wenlong Wang, Xinying Li.

   BACKGROUND: Prolyl-4-hydroxylase-A2 (P4HA2) is a pivotal enzyme involved in the regulation of tumorigenesis and progression. However, the precise biological roles and potential functions of P4HA2 in papillary thyroid cancer (PTC) remain poorly elucidated.
METHODS: Gain-of-function and loss-of-function approaches were employed to investigate the underlying biological effects of P4HA2 on PTC cell proliferation and metastasis both in vitro and in vivo. Furthermore, RIP assay, MeRIP assay, polysome fractionation, dual luciferase reporter assay, LC-MS/MS, and rescue experiments were conducted to explore the intricate relationships between YTHDF3, P4HA2 and Hippo signaling pathway.
RESULTS: P4HA2 exhibited significant up-regulation in PTC and was associated with unfavorable clinical characteristics and prognosis. In vitro and in vivo experiments demonstrated that P4HA2 promoted PTC cell proliferation and metastasis, while also contributing to tumorigenesis through the activation of glycolysis. Mechanistically, P4HA2 facilitated hydroxylation-mediated ubiquitination and degradation of SAV1, leading to enhanced expression of YAP1 in the Hippo signaling pathway. Additionally, YTHDF3 binding to P4HA2 mRNA in an N6-methyladenosine (m6A)-dependent manner decreased its stability, thereby inhibiting glycolysis in PTC.
CONCLUSION: The YTHDF3-regulated P4HA2 acts as an oncogenic factor, regulating glycolysis in PTC through the Hippo signaling pathway. This suggests that P4HA2 holds potential as a promising diagnostic marker and therapeutic target for patients with PTC.

Keywords:  Glycolysis; Hippo signaling pathway; P4HA2; Papillary thyroid cancer; YTHDF3

DOI:  https://doi.org/10.1016/j.ijbiomac.2024.139150
Mol Cell Pediatr. 2024 Dec 21. 11(1): 14

Myocardial mRNA expression of interleukin-6 and hypoxia inducible factor-1α in neonates with congenital cardiac defects.

Nesrine Farhat, Jaime Vazquez-Jimenez, Ruth Heying, Marie-Christine Seghaye.

   BACKGROUND: In neonates with congenital heart disease (CHD), myocardial remodelling involves activation of inflammatory pathways. The role of hypoxemia related pathways is however unknown. This study was therefore designed to investigate myocardial mRNA expression of interleukin (IL)-6 and hypoxia-inducible factor (HIF)-1α in neonates with CHD and analyse its influence on post-operative outcome.
RESULTS: 14 neonates with CHD scheduled for open cardiac surgery were studied. In group 1 (n = 5), pre-operative transcutaneous arterial oxygen saturation (SaO2) was ≤ 85% and in group 2 (n = 9) > 85%. Expression of IL-6- and HIF-1α-mRNA was studied on right atrial biopsy by RT-PCR and corelated to post-operative (po) outcome. Group 1 patients showed higher mean arterial blood pressure (MAP) and lower glycaemia 4 h po (p = 0.047 and p = 0.021, respectively). In the whole cohort, SaO2 correlated negatively with MAP (Pearson R: -0.662, p = 0.010). mRNA coding for IL-6 and HIF-1α was detected in the myocardium of all neonates independently of age, gender, or type of CHD. IL6-mRNA expression was not influenced by pre-operative hypoxemia but was associated with higher lactate levels in early po period (Pearson R: 0,611, p = 0,020). HIF-1α-mRNA expression correlated negatively with pre-operative SaO2 (Pearson R: -0.551, p = 0.04) and with aspartate aminotransferase levels 4 h po (Pearson R: 0.625, p = 0.017).
CONCLUSION: Our study shows that besides inflammatory pathways, hypoxemia related pathways are activated in the myocardium of neonates with CHD. Myocardial expression of both IL-6-mRNA and HIF-1α-mRNA relates to biological markers of a worse po outcome.

Keywords:  Congenital heart disease; Gene expression; HIF-1α; IL-6; Myocardium; Neonates; Post-operative outcome

DOI:  https://doi.org/10.1186/s40348-024-00187-5
Front Cell Dev Biol. 2024 ;12 1488877

Impact of galectin-3 on neurotrophic factor expression by PCR array: potential implications for the human cornea.

Ashley M Woodward, Pablo Argüeso.

  The cornea is densely innervated to maintain the integrity of the ocular surface, facilitating functions such as sensation and tear production. Following damage, alterations in the corneal microenvironment can profoundly affect its innervation, potentially impairing healing and sensory perception. One protein frequently upregulated at the ocular surface following tissue damage is galectin-3, but its contribution to corneal nerve regeneration remains unclear. Here, we sought to delineate the role of galectin-3 in regulating the expression of neurotrophic factors by different human cell types. Using a pathway-focused PCR array, we first evaluated the expression of neurotrophic factors in primary cultures of human corneal epithelial cells and fibroblasts. We found that these cell types contributed differently to the expression of these factors, with fibroblasts exhibiting higher levels of nerve growth factor, brain-derived neurotrophic factor, and GDNF compared to epithelial cells. Treatment with exogenous galectin-3 did not significantly affect epithelial cells; however, it did lead to increased synthesis and secretion of IL6, a cytokine known to influence neuronal survival and modulate inflammatory responses, by corneal fibroblasts. Using the human-derived SH-SY5Y cell line as a neuron-like cell model, we also found that galectin-3 stimulated the expression of FOS and LIF, two genes involved in neural differentiation and survival. In summary, these in vitro findings suggest that the presence of galectin-3 in the corneal environment may influence the neuronal response to injury.

Keywords:  cornea; epithelium; fibroblast; galectin-3; interleukin 6; neurotrophic factors

DOI:  https://doi.org/10.3389/fcell.2024.1488877
Sci Rep. 2024 Dec 28. 14(1): 30764

Effects of Empagliflozin and Dapagliflozin in alleviating cardiac fibrosis through SIRT6-mediated oxidative stress reduction.

Hong-Xia Ma, Ke Wu, Fei-Hong Dong, Bing-Kun Cai, Di Wu, Hui-Yi Lu.

  Sodium-glucose co-transport protein 2 (SGLT2) inhibitors, a novel category of oral hypoglycemic agents, offer a promising outlook for individuals experiencing heart failure with reduced ejection fraction. Evidence is emerging that highlights their potential in alleviating myocardial fibrosis and oxidative stress. However, the precise mechanisms through which SGLT2 inhibitors influence myocardial fibrosis induced by angiotensin II (Ang II) or transforming growth factor-β1 (TGF-β1) are not fully understood. This study aims to explore the intricate mechanisms by which SGLT2 inhibitors ameliorate myocardial fibrosis, particularly focusing on the nuanced interplay within the SIRT6 signaling pathway. Primary cardiac fibroblasts were isolated from the hearts of 1-3-day-old neonatal KM mice, were stimulated with Ang II or TGF-β1 to establish an in vitro model of myocardial fibrosis. Treatment with 10 µM Empagliflozin (EMPA) and Dapagliflozin (DAPA) significantly curtailed the proliferation of cardiac fibroblasts, substantially reduced collagen expression induced by Ang II/TGF-β1, and mitigated the phenotypic transformation and oxidative stress response. SIRT6, which is closely associated with myocardial fibrosis, demonstrated that the suppression its expression attenuated the protective effects of EMPA and DAPA against myocardial fibrosis and oxidative stress. Our findings suggest that SGLT2 inhibitors markedly decrease the Ang II/TGF-β1-induced transformation of cardiac fibroblasts to a myofibroblast phenotype by upregulating SIRT6 protein expression, thereby inhibiting oxidative stress and ameliorating myocardial fibrosis.

Keywords:  Dapagliflozin; Empagliflozin; Myocardial fibrosis; Oxidative stress injury; SIRT6

DOI:  https://doi.org/10.1038/s41598-024-80829-w
Invest Ophthalmol Vis Sci. 2024 Dec 02. 65(14): 38

Integrated Profiling of Extracellular Vesicle microRNA Impact on Trabecular Meshwork mRNA Expression: Insights From Microarray Analysis.

Efrat Cohen-Davidi, Valeria Feinstein, Boris Knyazer, Elie Beit-Yannai, Isana Veksler-Lublinsky.

Purpose: Extracellular vesicles (EVs) secreted by non-pigmented ciliary epithelial (NPCE) cells under oxidative stress may contribute to primary open-angle glaucoma (POAG) pathogenesis by altering gene expression in human trabecular meshwork (HTM) cells. This study investigated the impact of microRNAs (miRNAs) carried by NPCE-derived EVs on HTM cell gene expression under oxidative stress conditions.
Methods: NPCE cells were exposed to oxidative stress, and EVs were isolated from control and stressed cells. HTM cells were treated with these EVs, followed by microarray analysis to identify differentially expressed miRNAs in EVs and messenger RNAs (mRNAs) in HTM cells. Bioinformatics analysis was used to explore miRNA-mRNA interactions, enriched Gene Ontology (GO) terms, and miRNA-mRNA-GO networks.
Results: The study identified 54 differentially expressed miRNAs in stressed NPCE EVs. In HTM cells treated with stressed NPCE EVs, 88 genes were upregulated and 58 downregulated. GO analysis of upregulated genes showed enrichment in processes such as extracellular matrix organization, cell proliferation, and adhesion. Downregulated genes were associated with oxidative phosphorylation and adenosine triphosphate (ATP) biosynthesis. Notably, 59 out of 88 upregulated genes are known targets of downregulated miRNAs. Network analysis identified interactions between downregulated miRNAs and upregulated genes involved in key biological processes relevant to POAG pathogenesis.
Conclusions: This study provides new insights into the potential role of NPCE-derived EVs and their miRNA cargo in POAG, suggesting novel mechanisms for disease progression and potential therapeutic targets for further investigation.

DOI: https://doi.org/10.1167/iovs.65.14.38
Sci Rep. 2024 Dec 28. 14(1): 30938

SALL4 mediates SHP2 inhibition in myocardial fibroblasts through the DOT1L/H3K79me2 signaling pathway to promote the progression of myocardial infarction.

Yanhong Zong, Ming Zhao, Zhipeng Tang, Yanqing Tie, Kenan Peng, He Tan.

   OBJECTIVE: To explore the influence of SALL4 in cardiac fibroblasts on the progression of myocardial infarction.
METHODS: Analysis of genes specifically expressed in myocardial infarction by bioinformatics methods; The impact of SALL4 on myocardial infarction was assessed using mouse ultrasound experiments and Masson staining; The effect of SALL4 on the expression levels of collagen-I and collagen-III in myocardial tissue was examined by immunohistochemical staining; The migration ability of cardiac fibroblasts was evaluated using a Transwell assay; The proliferative ability of cardiac fibroblasts was tested using a CCK-8 assay; The relative fluorescence intensity of α-SMA and CTGF in cardiac fibroblasts were checked through immunofluorescence staining experiment; The expression of SALL4, DOT1L, H3K79me2, P53, SHP2, YAP, nucleus-YAP, collagen-I, α-SMA, CTGF, and PAI-1 in myocardial tissues or cardiac fibroblasts was detected using western blot analysis.
RESULTS: SALL4-specific high expression in myocardial infarction; SALL4 intensified the alterations in the heart structure of mice with myocardial infarction and worsened the fibrosis of myocardial infarction; SALL4 also promoted the expression of SALL4, DOT1L, H3K79me2, P53, SHP2, YAP, nucleus-YAP, collagen-I, collagen-III, α-SMA, CTGF, and PAI-1 in myocardial infarction tissues and cardiac fibroblasts; Subsequently, SALL4 could enhance the immunofluorescence intensity of α-SMA and CTGF; Moreover, SALL4 could promote the proliferation and migration of cardiac fibroblasts.
CONCLUSION: In cardiac fibroblasts, SALL4 mediates the DOT1L/H3K79me2 signaling pathway to inhibit SHP2, which then promotes the YAP/TAZ signaling pathway, thereby facilitating the progression of myocardial infarction.

Keywords:  Cardiac fibroblasts; DOT1L/H3K79me2; Myocardial infarction; SALL4; SHP2

DOI:  https://doi.org/10.1038/s41598-024-81815-y
Adv Rheumatol. 2024 Dec 23. 64(1): 91

Evaluating the role of active TGF-β1 as inflammatory biomarker in Kashmiri (North-Indian) patients with systemic sclerosis: a case-control study.

Sakeena Ayub, Tabasum Shafi, Roohi Rasool, Mushtaq A Dangroo, Muzaffar A Bindroo, Ayaz Gull, Lamya Ahmad Al-Keridis, Nawaf Alshammari, Mohd Saeed, Zafar Amin Shah.

   BACKGROUND: As a master immune system regulator, transforming growth factor β1 (TGF-β1) is closely linked to the complicated pathophysiology and development of systemic sclerosis (SSc), a multisystem fibrotic disease.
OBJECTIVE: We aim to evaluate the transcriptional levels of TGF-β1 mRNA in PBMCs, assess the TGF-β1 serum levels of SSc patients, and compare them with those of healthy subjects.
METHODS: PBMCs were isolated from whole blood of 50 SSc patients and in 30 healthy controls. After total RNA was extracted from isolated PBMCs, complementary DNA (cDNA) synthesis was performed. Afterward, the expression of TGF-β1 mRNA was assessed using quantitative real-time PCR using the SYBR Green, GAPDH, and TGF-β1 specific primers. The serum levels of TGF-β1 were determined using a commercially available ELISA kit.
RESULTS: There was a significant upregulation of TGF-β1 relative expression (p < 0.0001), when SSc patients were compared to the control group. The diffuse subgroup was more common in patients with elevated TGF-β1 mRNA expression (p < 0.0001). However, an insignificant difference was observed between the disease subsets of SSc. Serum TGF- β1 levels were upregulated in SSc patients (78.35 ± 23.16) compared to healthy subjects (61.06 ± 15.90), and were considerably higher in SSc patients with ILD (p < 0.01) and positive anti-topo-Isomerase antibody (p < 0.0001).
CONCLUSION: In patients with SSc, elevated levels of TGF-β1 in serum and their correlation with clinical symptoms imply that this cytokine may serve as a marker for fibrotic and vascular involvement in SSc.

Keywords:  ELISA; Systemic sclerosis; TGF-β1; mRNA expression; qRT-PCR

DOI:  https://doi.org/10.1186/s42358-024-00433-4
Cent Eur J Immunol. 2024 ;49(3): 238-251

Knockdown of BATF alleviates lung injury in septic neonates through transcriptional regulation of COTL1.

Jihui Zhang, Huimin Jiang.

   Introduction: Neonatal sepsis (NS) seriously threatens the health of infants. Coactosin-like protein 1 (COTL1) is a binding protein of F-actin and 5-lipoxygenase which is known to regulate the progression of neonatal sepsis. Nevertheless, the function of COTL1 in NS is not clear.
Material and methods: An in vivo model of NS was established using cecal slurry (CS). H&E staining was applied for observing the severity of lung injury in tissues of mice. MTT assay was applied for determining cell viability, and the inflammatory factors were examined using ELISA. Apoptosis was assessed via flow cytometry. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) levels were assessed by commercial kits. The interaction between basic leucine zipper ATF-like transcription factor (BATF) and COTL1 was verified using dual luciferase reporter and chromatin immunoprecipitation (ChIP) assay.
Results: COTL1 knockdown alleviated the progression of NS-induced lung injury. COTL1 knockdown enhanced the viability and decreased interleukin (IL)-6 and IL-1 β levels in lipopolysaccharides (LPS)-stimulated pulmonary microvascular endothelial cells. Silencing of COTL1 inhibited LPS induced apoptosis and oxidative stress. More importantly, BATF activated MAPK/NF-κB signaling through transcriptionally upregulating COTL1. Furthermore, BATF improved the LPS-induced inflammatory response and apoptosis in pulmonary microvascular endothelial cells through mediation of COTL1.
Conclusions: BATF knockdown alleviated NS-induced lung injury by activating the MAPK/NF-κB pathway via transcriptionally upregulating COTL1 expression.

Keywords:  BATF; COTL1; lung injury; neonatal sepsis; oxidative stress

DOI:  https://doi.org/10.5114/ceji.2024.144865
Adv Respir Med. 2024 Nov 27. 92(6): 485-503

Molecular Pathophysiology of Chronic Thromboembolic Pulmonary Hypertension: A Clinical Update from a Basic Research Perspective.

Leslie Marisol Gonzalez-Hermosillo, Guillermo Cueto-Robledo, Dulce Iliana Navarro-Vergara, Maria Berenice Torres-Rojas, Marisol García-Cesar, Oscar Pérez-Méndez, Galileo Escobedo.

  Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but severe condition characterized by persistent obstruction and vascular remodeling in the pulmonary arteries following an acute pulmonary embolism (APE). Although APE is a significant risk factor, up to 25% of CTEPH cases occur without a history of APE or deep vein thrombosis, complicating the understanding of its pathogenesis. Herein, we carried out a narrative review discussing the mechanisms involved in CTEPH development, including fibrotic thrombus formation, pulmonary vascular remodeling, and abnormal angiogenesis, leading to elevated pulmonary vascular resistance and right heart failure. We also outlined how the disease's pathophysiology reveals both proximal and distal pulmonary artery obstruction, contributing to the development of pulmonary hypertension. We depicted the risk factors predicting CTEPH, including thrombotic history, hemostatic disorders, and certain medical conditions. We finally looked at the molecular mechanisms behind the role of endothelial dysfunction, gene expression alterations, and inflammatory processes in CTEPH progression and detection. Despite these insights, there is still a need for improved diagnostic tools, biomarkers, and therapeutic strategies to enhance early detection and management of CTEPH, ultimately aiming to reduce diagnostic delay and improve patient outcomes.

Keywords:  acute pulmonary embolism; chronic thromboembolic pulmonary hypertension; fibrotic thrombus formation; gene expression; pulmonary hypertension; pulmonary vascular remodeling

DOI:  https://doi.org/10.3390/arm92060044
RNA. 2024 Dec 24. pii: rna.080259.124. [Epub ahead of print]

N6-methyladenosine reader YTHDF2 in cell state transition and antitumor immunity.

Liangliang Wang, Ralph R Weichselbaum, Chuan He.

Recent studies revealed that the YTHDF family proteins bind preferentially to the N6-methyladenosine (m6A)-modified mRNA and regulate functions of these RNAs in different cell types. YTHDF2, the first identified m6A reader in mammals, has garnered significant attention because of its profound effect to regulate the m6A epitranscriptome in multiple biological processes. Here, we review current knowledge on the mechanisms by which YTHDF2 exerts its functions and discuss recent advances that underscore the multifaceted role of YTHDF2 in development, stem cell expansion and immune evasion. We also highlight potential therapeutic interventions targeting the m6A/YTHDF2 axis to improve the response to current antitumor therapies.

DOI: https://doi.org/10.1261/rna.080259.124
Exp Eye Res. 2024 Dec 20. pii: S0014-4835(24)00444-5. [Epub ahead of print]251 110222

Taurine mechanism in preventing retinal cell damage from acute ocular hypertension through GTPBP3 regulation.

Wei Lu, Yuting Yang, Shunxiang Gao, Jihong Wu, Xinghuai Sun.

  We aimed to explore the protective effects and underlying mechanisms of taurine on retinal cells during acute ocular hypertension (AOH)-induced damage. Retinal morphology, apoptosis, mitochondrial structure, electroretinography, expression of GTP binding protein 3 (GTPBP3), and molecules in the unfolded protein response (UPR) were examined in an AOH mouse model and wild-type (WT) mice with or without intravitreal injection of taurine. For in vitro experiments, the GTPBP3 expression and endoplasmic reticulum (ER) stress were examined in R28 cell line under hydrogen peroxide (H2O2)-induced damage or hypoxia/reoxygenation (H/R)-induced damage, with or without taurine pretreatment. Taurine pretreatment alleviated retinal damage caused by AOH modeling. The GTPBP3 expression level decreased after AOH injury, and taurine pretreatment reversed this reduction. Retinas with decreased GTPBP3 expression showed reduced retinal ganglion cell (RGC) function, which could be reversed by intravitreal taurine injection. In H2O2-, H/R-, and AOH-induced damage, UPR were activated and alleviated by taurine pretreatment. GTPBP3 knockdown in R28 cells also activated the UPR, which was alleviated by taurine. A UPR activator downregulated GTPBP3 levels in normal R28 cells, whereas a UPR inhibitor upregulated GTPBP3 levels in GTPBP3 knockdown R28 cells. In conclusion, this study provides important evidence that taurine prevents retinal cell damage in mice exposed to AOH and modulates GTPBP3 expression via the UPR pathway. Interventions targeting this mechanism can be used as potential therapeutic targets for AOH damage.

Keywords:  Acute ocular hypertension; GTPBP3; Mitochondria; Taurine; Unfolded protein response

DOI:  https://doi.org/10.1016/j.exer.2024.110222
bioRxiv. 2024 Dec 09. pii: 2024.12.05.627027. [Epub ahead of print]

Transcriptomic changes in retinal ganglion cell types associated with the disruption of cholinergic retinal waves.

Rachana Deven Somaiya, Matthew A Po, Marla B Feller, Karthik Shekhar.

In the early stages of retinal development, a form of correlated activity known as retinal waves causes periodic depolarizations of immature retinal ganglion cells (RGCs). Retinal waves are crucial for refining visual maps in the brain's retinofugal targets and for the development of retinal circuits underlying feature detection, such as direction selectivity. Yet, how waves alter gene expression in immature RGCs is poorly understood, particularly at the level of the many distinct types of RGCs that underlie the retina's ability to encode diverse visual features. We performed single-cell RNA sequencing on RGCs isolated at the end of the first postnatal week from wild-type (WT) mice and β2KO mice, which lack the β2 subunit of the nicotinic acetylcholine receptor, leading to the disruption of cholinergic retinal waves. Statistical comparisons of RGC transcriptomes between the two conditions reveal a weak impact of retinal waves on RGC diversity, indicating that retinal waves do not influence the molecular programs that instruct RGC differentiation and maturation. Although wave-dependent gene expression changes are modest in the global sense, we identified ∼238 genes that are significantly altered in select subsets of RGC types. We focused on one gene, Kcnk9 , which encodes the two-pore domain leak channel potassium channel TASK3. Kcnk9 , which is highly enriched in αRGCs, was strongly downregulated in β2KO. We validated this result using in situ hybridization and performed whole-cell recording to demonstrate a significant decrease in the leak conductance in β2KO RGCs. Our dataset provides a useful resource for identifying potential targets of spontaneous activity-dependent regulation of neurodevelopment in the retina.

DOI: https://doi.org/10.1101/2024.12.05.627027
Sci Rep. 2024 Dec 28. 14(1): 30738

Changes in MicroRNAs expression mediate molecular mechanism underlying the effect of MeJA on the biosynthesis of podophyllotoxin in Linum album cells.

Mostafa Sagharyan, Mohsen Sharifi, Elaheh Samari, Farah Karimi.

  Podophyllotoxin (PTOX), produced by Linum album, is a monolignol that participates in plant defense strategies. Our previous study established that methyl jasmonate (MeJA) significantly stimulates PTOX production in L. album cells. However; the mechanisms by which MeJA regulates PTOX biosynthesis are uncovered. In the present study, we demonstrated that MeJA induces a time-dependent hydrogen peroxide (H2O2) and salicylic acid (SA) accumulation but reduces nitric oxide (NO) generation in L. album cells. PTOX biosynthetic genes such as PAL, CCR, CAD, and PLR were upregulated in response to MeJA exposure. Furthermore, the results of RT-qPCR revealed a positive correlation between the expression of PTOX biosynthetic genes and MeJA-induced upregulation of four miRNAs such as miR156, miR159, miR172, and miR396 at 12 h. Generally, this study revealed that MeJA mediates PTOX biosynthesis in L. album cells by inducing H2O2 and SA formation, which can probably upregulate the expression level of some miRNAs and biosynthetic genes in a redox balance-dependent manner.

Keywords:   Linum album ; Hydrogen peroxide; Methyl jasmonate; Podophyllotoxin; Salicylic acid; miRNAs

DOI:  https://doi.org/10.1038/s41598-024-78715-6
Sci Rep. 2024 Dec 28. 14(1): 31017

PCNA and Rnh1 independently participate in the protection of mitochondrial genome against UV-induced mutagenesis in yeast cells.

Martyna Latoszek, Katarzyna Baginska-Drabiuk, Ewa Sledziewska-Gojska, Aneta Kaniak-Golik.

In Saccharomyces cerevisiae cells, the bulk of mitochondrial DNA (mtDNA) replication is mediated by the replicative high-fidelity DNA polymerase γ. However, upon UV irradiation low-fidelity translesion polymerases: Polη, Polζ and Rev1, participate in an error-free replicative bypass of UV-induced lesions in mtDNA. We analysed how translesion polymerases could function in mitochondria. We show that, contrary to expectations, yeast PCNA is mitochondrially localized and, upon genotoxic stress, ubiquitinated PCNA can be detected in purified mitochondria. Moreover, the substitution K164R in PCNA leads to an increase of UV-induced point mutations in mtDNA. This UV-dependent effect is highly enhanced in cells in which the Mec1/Rad53/Dun1 checkpoint-dependent deoxynucleotide triphosphate (dNTP) increase in response to DNA damage is blocked and RNase H1 is lacking, suggesting that PCNA plays a role in a replication damage bypass pathway dealing with lesions in multiple ribonucleotides embedded in mtDNA. In addition, our analysis indicates that K164R in PCNA restricts mostly the anti-mutagenic Polη activity on UV-damaged mtDNA, whereas the inhibitory effect on Polζ's activity is only partial. We also show for the first time that in conditions of dNTP depletion yeast Rnh1 neutralizes deleterious effects of ribonucleotides for mtDNA replication, thereby preventing the enhanced instability of rho+ mitochondrial genomes.

DOI: https://doi.org/10.1038/s41598-024-82104-4