A Novel Mechanism of Sigma 1 Receptor Neuroprotection: Modulation of miR-214-3p

Navigating the future of retinitis pigmentosa treatments: A comprehensive analysis of therapeutic approaches in rd10 mice

Retinitis pigmentosa (RP) is a degenerative disease, caused by genetic mutations that lead to a loss in photoreceptors. For research on RP, rd10 mice, which carry mutations in the phosphodiesterase (PDE) gene, exhibit degenerative patterns comparable to those of patients with RP, making them an ideal model for investigating potential treatments. Although numerous studies have reported the potential of biochemical drugs, gene correction, and stem cell transplantation in decelerating rd10 retinal degeneration, a comprehensive review of these studies has yet to be conducted. Therefore, here, a comparative analysis of rd10 mouse treatment research over the past decade was performed. Our findings suggest that biochemical drugs capable of inhibiting the inflammatory response may be promising therapeutics. Additionally, significant progress has been made in the field of gene therapy; nevertheless, challenges such as strict delivery requirements, bystander editing, and off-target effects still need to be resolved. Nevertheless, secretory function is the only unequivocal protective effect of stem cell transplantation. In summary, this review presents a comprehensive analysis and synthesis of the treatment approaches employing rd10 mice as experimental subjects, describing a clear pathway for future RP treatment research and identifies potential clinical interventions.

Normospermic Patients Infected With Ureaplasma parvum: Role of Dysregulated miR-122-5p, miR-34c-5, and miR-141-3p

Background

Ureaplasma parvum (UP) is a causative agent of non-gonococcal urethritis, involved in the pathogenesis of prostatitis and epididymitis, and it could impair human fertility. Although UP infection is a frequent cause of male infertility the study evidence assessing their prevalence and the association in patients with infertility is still scarce. The molecular processes leading to defects in spermatozoa quality are not completely investigated. MicroRNAs (miRNAs) have been extensively reported as gene regulatory molecules on post-transcriptional levels involved in various biological processes such as gametogenesis, embryogenesis, and the quality of sperm, oocyte, and embryos.

Methods

Therefore, the study design was to demonstrate that miRNAs in body fluids like sperm could be utilized as non-invasive diagnostic biomarkers for pathological and physiological conditions such as infertility. A post-hoc bioinformatics analysis was carried out to predict the pathways modulated by the miRNAs dysregulated in the differently motile spermatozoa.

Results

Here it is shown that normospermic patients infected by UP had spermatozoa with increased quantity of superoxide anions, reduced expression of miR-122-5p, miR-34c-5, and increased miR-141-3p compared with non-infected normospermic patients. This corresponded to a reduction of sperm motility in normospermic infected patients compared with normospermic non-infected ones. A target gene prediction presumed that an essential role of these miRNAs resided in the regulation of lipid kinase activity, accounting for the changes in the constitution of spermatozoa membrane lipids caused by UP.

Conclusions

Altogether, the data underline the influence of UP on epigenetic mechanisms regulating spermatozoa motility.

Serum miRNA modulations indicate changes in retinal morphology

Background

Age-related macular degeneration (AMD) is the leading cause of vision loss in the developed world and the detection of its onset and progression are based on retinal morphological assessments. MicroRNA (miRNA) have been explored extensively as biomarkers for a range of neurological diseases including AMD, however differences in experimental design and the complexity of human biology have resulted in little overlap between studies. Using preclinical animal models and clinical samples, this study employs a novel approach to determine a serum signature of AMD progression.

Methods

Serum miRNAs were extracted from mice exposed to photo-oxidative damage (PD; 0, 1, 3 and 5 days), and clinical samples from patients diagnosed with reticular pseudodrusen or atrophic AMD. The expression of ~800 miRNAs was measured using OpenArray™, and differential abundance from controls was determined using the HTqPCR R package followed by pathway analysis with DAVID. MiRNA expression changes were compared against quantifiable retinal histological indicators. Finally, the overlap of miRNA changes observed in the mouse model and human patient samples was investigated.

Results

Differential miRNA abundance was identified at all PD time-points and in clinical samples. Importantly, these were associated with inflammatory pathways and histological changes in the retina. Further, we were able to align findings in the mouse serum to those of clinical patients.

Conclusion

In conclusion, serum miRNAs are a valid tool as diagnostics for the early detection of retinal degeneration, as they reflect key changes in retinal health. The combination of pre-clinical animal models and human patient samples led to the identification of a preliminary serum miRNA signature for AMD. This study is an important platform for the future development of a diagnostic serum miRNA panel for the early detection of retinal degeneration.

Sigma-1 Receptor in Retina: Neuroprotective Effects and Potential Mechanisms

Retinal degenerative diseases are the major factors leading to severe visual impairment and even irreversible blindness worldwide. The therapeutic approach for retinal degenerative diseases is one extremely urgent and hot spot in science research. The sigma-1 receptor is a novel, multifunctional ligand-mediated molecular chaperone residing in endoplasmic reticulum (ER) membranes and the ER-associated mitochondrial membrane (ER-MAM); it is widely distributed in numerous organs and tissues of various species, providing protective effects on a variety of degenerative diseases. Over three decades, considerable research has manifested the neuroprotective function of sigma-1 receptor in the retina and has attempted to explore the molecular mechanism of action. In the present review, we will discuss neuroprotective effects of the sigma-1 receptor in retinal degenerative diseases, mainly in aspects of the following: the localization in different types of retinal neurons, the interactions of sigma-1 receptors with other molecules, the correlated signaling pathways, the influence of sigma-1 receptors to cellular functions, and the potential therapeutic effects on retinal degenerative diseases.

Revisiting the sigma-1 receptor as a biological target to treat affective and cognitive disorders

Depression and cognitive disorders are diseases with complex and not-fully understood etiology. Unfortunately, the COVID-19 pandemic dramatically increased the prevalence of both conditions. Since the current treatments are inadequate in many patients, there is a constant need for discovering new compounds, which will be more effective in ameliorating depressive symptoms and treating cognitive decline. Proteins attracting much attention as potential targets for drugs treating these conditions are sigma-1 receptors. Sigma-1 receptors are multi-functional proteins localized in endoplasmic reticulum membranes, which play a crucial role in cellular signal transduction by interacting with receptors, ion channels, lipids, and kinases. Changes in their functions and expression may lead to various diseases, including depression or memory impairments. Thus, sigma-1 receptor modulation might be useful in treating these central nervous system diseases. Importantly, two sigma-1 receptor ligands entered clinical trials, showing that this compound group possesses therapeutic potential. Therefore, based on preclinical studies, this review discusses whether the sigma-1 receptor could be a promising target for drugs treating affective and cognitive disorders.

Emerging Benefits: Pathophysiological Functions and Target Drugs of the Sigma-1 Receptor in Neurodegenerative Diseases

The sigma-1 receptor (Sig-1R) is encoded by the SIGMAR1 gene and is a nonopioid transmembrane receptor located in the mitochondrial-associated endoplasmic reticulum membrane (MAM). It helps to locate endoplasmic reticulum calcium channels, regulates calcium homeostasis, and acts as a molecular chaperone to control cell fate and participate in signal transduction. It plays an important role in protecting neurons through a variety of signaling pathways and participates in the regulation of cognition and motor behavior closely related to neurodegenerative diseases. Based on its neuroprotective effects, Sig-1R has now become a breakthrough target for alleviating Alzheimer's disease and other neurodegenerative diseases. This article reviews the most cutting-edge research on the function of Sig-1R under normal or pathologic conditions and target drugs of the sigma-1 receptor in neurodegenerative diseases.

The roles of long non-coding RNAs in ocular diseases

In recent years, lncRNAs have been shown to regulate gene expression at the epigenetic, transcriptional and translational level, thus exerting various functions in biological and pathological processes involving cell proliferation, apoptosis, cell cycle and immune response. An increasing number of researches have unveiled that lncRNAs are dysregulated in pathogenesis and the development of different ocular diseases, such as glaucoma, cataract, retinal disease and ocular tumors. Also, it has been reported that lncRNAs may exert significant roles in various ocular diseases. Here, we summarized the functions of lncRNAs on relevant ocular diseases and further clarified their mechanisms. Here, several previous studies with detailed information of lncRNAs which have been proved to be the diagnostic or prognostic biomarkers and potential therapeutic targets were included. Also, it is our hope to provide a thorough knowledge of the functions of lncRNAs in eye diseases and the methods by which lncRNAs can influence ocular diseases.

MicroRNA-126a-5p Exerts Neuroprotective Effects on Ischemic Stroke via Targeting NADPH Oxidase 2

BACKGROUND

Ischemic stroke is a destructive cerebrovascular disorder related to oxidative stress; NOX2 is a major source for ROS production; and miR-126a-5p is involved in several diseases, such as abdominal aortic aneurysm. We investigated the role of miR-126a-5p in regulating NOX2 in ischemic stroke.

METHODS

MiR-126a-5p and NOX2 were examined in the brains of rats subjected to cerebral ischemia/reperfusion (I/R) by RT-PCR and Western blot. MiR-126a-5p agomir was delivered to examine the effects of miR-126a-5p on I/R injury. The neurological deficit, infarct volume, and brain water content were evaluated. NOX activity, ROS production, and MDA and SOD levels were detected to assess oxidative stress. H&E staining was used to examine cell state. Apoptosis was evaluated by TUNEL, caspase-3 activity, and cleaved-caspase-3 protein level. The relationship between miR-126a-5p and NOX2 was analyzed by bioinformatics and luciferase reporter assay. MiR-126a-5p mimic, miR-126a-5p inhibitor, or pcDNA-NOX2 were transfected in SH-SY5Y cells to further assess the effects of miR-126a-5p on OGD/R-induced cells injury.

RESULTS

NOX2 was upregulated and miR-126a-5p was down-regulated in the brains of I/R rats. MiR-126a-5p agomir obviously reduced the neurological deficit, infarct volume, brain water content, oxidative stress, and apoptosis in I/R rats. MiR-126a-5p targeted NOX2 directly and regulated NOX2 negatively. Moreover, miR-126a-5p mimic elevated cell viability and inhibited oxidative stress and apoptosis in OGD/R-treated SH-SY5Y cells, while miR-126a-5p inhibitor had the opposite effects. NOX2 overexpression antagonized the protective effects of miR-126a-5p mimic on OGD/R-induced cell injury.

CONCLUSION

MiR-126a-5p is a novel potential target for ischemic stroke therapy due to its protection against cerebral I/R injury via directly targeting NOX2.

Chaperone Sigma1R and Antidepressant Effect

This review analyzes the current scientific literature on the role of the Sigma1R chaperone in the pathogenesis of depressive disorders and pharmacodynamics of antidepressants. As a result of ligand activation, Sigma1R is capable of intracellular translocation from the endoplasmic reticulum (ER) into the region of nuclear and cellular membranes, where it interacts with resident proteins. This unique property of Sigma1R provides regulation of various receptors, ion channels, enzymes, and transcriptional factors. The current review demonstrates the contribution of the Sigma1R chaperone to the regulation of molecular mechanisms involved in the antidepressant effect.

Knockdown of SNHG14 Alleviates MPP+-Induced Injury in the Cell Model of Parkinson's Disease by Targeting the miR-214-3p/KLF4 Axis

Background

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Long non-coding RNA (lncRNA) small nucleolar RNA host gene 14 (SNHG14) has been demonstrated as an important regulator in PD pathology. However, the functional mechanisms played by SNHG14 in PD remain largely unclear.

Methods

We used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium (MPP⁺) to establish PD mouse and cell models. The levels of SNHG14, miR-214-3p, and Krüppel-like factor 4 (KLF4) were gauged by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot analysis. Cell viability and apoptosis were determined using the Cell Counting-8 Kit (CCK-8) assay and flow cytometry, respectively. The levels of inflammatory cytokines were evaluated by ELISA. The relationships among SNHG14, miR-214-3p, and KLF4 were confirmed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

Results

Our data indicated that SNHG14 was upregulated and miR-214-3p was downregulated in PD models. SNHG14 knockdown ameliorated MPP⁺-stimulated damage in SK-N-SH cells, as evidenced by the enhancement in cell viability and the suppression in cell apoptosis and pro-inflammatory cytokine production. Mechanistically, SNHG14 directly targeted miR-214-3p via binding to miR-214-3p, and SNHG14 knockdown protected SK-N-SH cell from MPP⁺-stimulated cytotoxicity by upregulating miR-214-3p. KLF4 was a direct target of miR-214-3p, and SNHG14 regulated KLF4 expression by acting as a miR-214-3p sponge. Furthermore, miR-214-3p overexpression alleviated MPP⁺-stimulated damage in SK-N-SH cells by downregulating KLF4.

Conclusion

Our current study first demonstrated the protective effect of SNHG14 knockdown on MPP⁺-stimulated cytotoxicity in SK-N-SH cells at least partially by targeting the miR-214-3p/KLF4 axis, illuminating a promising target for PD intervention and treatment.

Recent Developments in Diabetic Retinal Neurodegeneration: A Literature Review

Neurodegeneration plays a significant role in the complex pathology of diabetic retinopathy. Evidence suggests the onset of neurodegeneration occurs early on in the disease, and so a greater understanding of the process is essential for prompt detection and targeted therapies. Neurodegeneration is a common pathway of assorted processes, including activation of inflammatory pathways, reduction of neuroprotective factors, DNA damage, and apoptosis. Oxidative stress and formation of advanced glycation end products amplify these processes and are elevated in the setting of hyperglycemia, hyperlipidemia, and glucose variability. These key pathophysiologic mechanisms are discussed, as well as diagnostic modalities and novel therapeutic avenues, with an emphasis on recent discoveries. The aim of this article is to highlight the crucial role of neurodegeneration in diabetic retinopathy and to review the molecular basis for this neuronal dysfunction, its diagnostic features, and the progress currently made in relevant therapeutic interventions.