Overexpression of CERKL Protects Retinal Pigment Epithelium Mitochondria from Oxidative Stress Effects

RNA methylation homeostasis in ocular diseases: All eyes on Me

RNA methylation is a pivotal epigenetic modification that adjusts various aspects of RNA biology, including nuclear transport, stability, and the efficiency of translation for specific RNA candidates. The methylation of RNA involves the addition of methyl groups to specific bases and can occur at different sites, resulting in distinct forms, such as N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), and 7-methylguanosine (m7G). Maintaining an optimal equilibrium of RNA methylation is crucial for fundamental cellular activities such as cell survival, proliferation, and migration. The balance of RNA methylation is linked to various pathophysiological conditions, including senescence, cancer development, stress responses, and blood vessel formation, all of which are pivotal for comprehending a spectrum of eye diseases. Recent findings have highlighted the significant role of diverse RNA methylation patterns in ophthalmological conditions such as age-related macular degeneration, diabetic retinopathy, cataracts, glaucoma, uveitis, retinoblastoma, uveal melanoma, thyroid eye disease, and myopia, which are critical for vision health. This thorough review endeavors to dissect the influence of RNA methylation on common and vision-impairing ocular disorders. It explores the nuanced roles that RNA methylation plays in key pathophysiological mechanisms, such as oxidative stress and angiogenesis, which are integral to the onset and progression of these diseases. By synthesizing the latest research, this review offers valuable insights into how RNA methylation could be harnessed for therapeutic interventions in the field of ophthalmology.

Progresses and perspectives on natural polysaccharide based hydrogels for repair of infarcted myocardium

Myocardial infarction (MI) is serious health threat and impairs the quality of life. It is a major causative factor of morbidity and mortality. MI leads to the necrosis of cardio-myocytes, cardiac remodelling and dysfunction, eventually leading to heart failure. The limitations of conventional therapeutic and surgical interventions and lack of heart donors have necessitated the evolution of alternate treatment approaches for MI. Polysaccharide hydrogel based repair of infarcted myocardium have surfaced as viable option for MI treatment. Polysaccharide hydrogels may be injectable hydrogels or cardiac patches. Injectable hydrogels can in situ deliver cells and bio-actives, facilitating in situ cardiac regeneration and repair. Polysaccharide hydrogel cardiac patches reduce cardiac wall stress, and inhibit ventricular expansion and promote angiogenesis. Herein, we discuss about MI pathophysiology and myocardial microenvironment and how polysaccharide hydrogels are designed to mimic and support the microenvironment for cardiac repair. We also put forward the versatility of the different polysaccharide hydrogels in mimicking diverse cardiac properties, and acting as a medium for delivery of cells, and therapeutics for promoting angiogenesis and cardiac repair. The objectives of this review is to summarize the factors leading to MI and to put forward how polysaccharide based hydrogels promote cardiac repair. This review is written to enable researchers understand the factors promoting MI so that they can undertake and design novel hydrogels for cardiac regeneration.

Antioxidant Hydrogels: Antioxidant Mechanisms, Design Strategies, and Applications in the Treatment of Oxidative Stress-Related Diseases

Oxidative stress is a biochemical process that disrupts the redox balance due to an excess of oxidized substances within the cell. Oxidative stress is closely associated with a multitude of diseases and health issues, including cancer, diabetes, cardiovascular diseases, neurodegenerative disorders, inflammatory conditions, and aging. Therefore, the developing of antioxidant treatment strategies has emerged as a pivotal area of medical research. Hydrogels have garnered considerable attention due to their exceptional biocompatibility, adjustable physicochemical properties, and capabilities for drug delivery. Numerous antioxidant hydrogels have been developed and proven effective in alleviating oxidative stress. In the pursuit of more effective treatments for oxidative stress-related diseases, there is an urgent need for advanced strategies for the fabrication of multifunctional antioxidant hydrogels. Consequently, the authors' focus will be on hydrogels that possess exceptional reactive oxygen species and reactive nitrogen species scavenging capabilities, and their role in oxidative stress therapy will be evaluated. Herein, the antioxidant mechanisms and the design strategies of antioxidant hydrogels and their applications in oxidative stress-related diseases are discussed systematically in order to provide critical insights for further advancements in the field.

Exacerbated response to oxidative stress in the Retinitis Pigmentosa CerklKD/KO mouse model triggers retinal degeneration pathways upon acute light stress

The retina is particularly vulnerable to genetic and environmental alterations that generate oxidative stress and cause cellular damage in photoreceptors and other retinal neurons, eventually leading to cell death. CERKL (CERamide Kinase-Like) mutations cause Retinitis Pigmentosa and Cone-Rod Dystrophy in humans, two disorders characterized by photoreceptor degeneration and progressive vision loss. CERKL is a resilience gene against oxidative stress, and its overexpression protects cells from oxidative stress-induced apoptosis. Besides, CERKL contributes to stress granule-formation and regulates mitochondrial dynamics in the retina. Using the CerklKD/KO albino mouse model, which recapitulates the human disease, we aimed to study the impact of Cerkl knockdown on stress response and activation of photoreceptor death mechanisms upon light/oxidative stress. After acute light injury, we assessed immediate or late retinal stress response, by combining both omic and non-omic approaches. Our results show that Cerkl knockdown increases ROS levels and causes a basal exacerbated stress state in the retina, through alterations in glutathione metabolism and stress granule production, overall compromising an adequate response to additional oxidative damage. As a consequence, several cell death mechanisms are triggered in CerklKD/KO retinas after acute light stress. Our studies indicate that Cerkl gene is a pivotal player in regulating light-challenged retinal homeostasis and shed light on how mutations in CERKL lead to blindness by dysregulation of the basal oxidative stress response in the retina.

CERKL, a Retinal Dystrophy Gene, Regulates Mitochondrial Transport and Dynamics in Hippocampal Neurons

Mutations in the Ceramide Kinase-like (CERKL) gene cause retinal dystrophies, characterized by progressive degeneration of retinal neurons, which eventually lead to vision loss. Among other functions, CERKL is involved in the regulation of autophagy, mitochondrial dynamics, and metabolism in the retina. However, CERKL is nearly ubiquitously expressed, and it has been recently described to play a protective role against brain injury. Here we show that Cerkl is expressed in the hippocampus, and we use mouse hippocampal neurons to explore the impact of either overexpression or depletion of CERKL on mitochondrial trafficking and dynamics along axons. We describe that a pool of CERKL localizes at mitochondria in hippocampal axons. Importantly, the depletion of CERKL in the Cerkl^KD/KO mouse model is associated with changes in the expression of fusion/fission molecular regulators, induces mitochondrial fragmentation, and impairs axonal mitochondrial trafficking. Our findings highlight the role of CERKL, a retinal dystrophy gene, in the regulation of mitochondrial health and homeostasis in central nervous system anatomic structures other than the retina.

Genetic dissection of non-syndromic retinitis pigmentosa

Retinitis pigmentosa (RP) belongs to a group of pigmentary retinopathies. It is the most common form of inherited retinal dystrophy, characterized by progressive degradation of photoreceptors that leads to nyctalopia, and ultimately, complete vision loss. RP is distinguished by the continuous retinal degeneration that progresses from the mid-periphery to the central and peripheral retina. RP was first described and named by Franciscus Cornelius Donders in the year 1857. It is one of the leading causes of bilateral blindness in adults, with an incidence of 1 in 3000 people worldwide. In this review, we are going to focus on the genetic heterogeneity of this disease, which is provided by various inheritance patterns, numerosity of variations and inter-/intra-familial variations based upon penetrance and expressivity. Although over 90 genes have been identified in RP patients, the genetic cause of approximately 50% of RP cases remains unknown. Heterogeneity of RP makes it an extremely complicated ocular impairment. It is so complicated that it is known as “fever of unknown origin”. For prognosis and proper management of the disease, it is necessary to understand its genetic heterogeneity so that each phenotype related to the various genetic variations could be treated.