Cathepsin A contributes to left ventricular remodeling by degrading extracellular superoxide dismutase in mice

Broadening Horizons: Exploring the Cathepsin Family as Therapeutic Targets for Alzheimer's Disease

Alzheimer's disease (AD) is an intricate neurodegenerative disorder characterized by the accumulation of misfolded proteins, including beta-amyloid (Aβ) and tau, leading to cognitive decline. Despite decades of research, the precise mechanisms underlying its onset and progression remain elusive. Cathepsins are a family of lysosomal enzymes that play vital roles in cellular processes, including protein degradation and regulation of immune responses. Emerging evidence suggests that cathepsins may be involved in AD pathogenesis. Cathepsins can influence the activation of microglia and astrocytes, the resident immune cells in the brain. However, cathepsin dysfunction may lead to the accumulation of misfolded proteins, notably Aβ and tau. In addition, dysregulated cathepsin activity may induce an exaggerated immune response, promoting chronic inflammation and neuronal dysfunction in patients with AD. By unraveling the classification, functions, and roles of cathepsins in AD's pathogenesis, this review sheds light on their intricate involvement in this devastating disease. Targeting cathepsin activity could be a promising and novel approach for mitigating the pathological processes that contribute to AD, providing new avenues for its treatment and prevention.

The Intricate Balance between Life and Death: ROS, Cathepsins, and Their Interplay in Cell Death and Autophagy

Cellular survival hinges on a delicate balance between accumulating damages and repair mechanisms. In this intricate equilibrium, oxidants, currently considered physiological molecules, can compromise vital cellular components, ultimately triggering cell death. On the other hand, cells possess countermeasures, such as autophagy, which degrades and recycles damaged molecules and organelles, restoring homeostasis. Lysosomes and their enzymatic arsenal, including cathepsins, play critical roles in this balance, influencing the cell's fate toward either apoptosis and other mechanisms of regulated cell death or autophagy. However, the interplay between reactive oxygen species (ROS) and cathepsins in these life-or-death pathways transcends a simple cause-and-effect relationship. These elements directly and indirectly influence each other's activities, creating a complex web of interactions. This review delves into the inner workings of regulated cell death and autophagy, highlighting the pivotal role of ROS and cathepsins in these pathways and their intricate interplay.

The many roles of cathepsins in restenosis

Drug-eluting stents (DES) and dual antiplatelet regimens have significantly improved the clinical management of ischemic heart disease; however, the drugs loaded with DES in clinical practice are mostly paclitaxel or rapamycin derivatives, which target symptoms of post implantation proliferation and inflammation, leading to delayed re-endothelialization and neo-atherosclerosis. Along with the treatments already in place, there is a need for novel strategies to lessen the negative clinical outcomes of DES delays as well as a need for greater understanding of their pathobiological mechanisms. This review concentrates on the function of cathepsins (Cats) in the inflammatory response and granulation tissue formation that follow Cat-induced damage to the vasculature scaffold, as well as the functions of Cats in intimal hyperplasia, which is characterized by the migration and proliferation of smooth muscle cells, and endothelial denudation, re-endothelialization, and/or neo-endothelialization. Additionally, Cats can alter essential neointima formation and immune response inside scaffolds, and if Cats are properly controlled in vivo, they may improve scaffold biocompatibility. This unique profile of functions could lead to an original concept for a cathepsin-based coronary intervention treatment as an adjunct to stent placement.

A randomized, placebo-controlled, trial to assess the photosensitizing, phototoxic and carcinogenic potential of hydrochlorothiazide in healthy volunteers

BACKGROUND AND AIMS

Pharmacovigilance reports, associating hydrochlorothiazide (HCT) with skin cancer, resulted in a significant decrease of HCT prescriptions for hypertension and heart failure. Whether HCT exhibits phototoxic properties thereby causing skin cancer remains unknown. This study aimed to examine the photosensitizing, phototoxic and carcinogenic potential of HCT in a randomized, placebo-controlled, double-blind trial in vivo and also in vitro .

METHODS

The trial assigned 30 healthy, normotensive adult volunteers in a 2:1 ratio to either HCT 25 mg/day or placebo for 15 days. Photosensitivity of the skin with and without the effect of HCT treatment were assessed. Following whole-body ultraviolet A (UVA) and B (UVB, 311 nm) irradiation, phototoxic and carcinogenic reactions by measuring urinary excretion of pyrimidine dimers were evaluated. For the in-vitro studies, human keratinocytes (HaCaT) were incubated with HCT, irradiated with UVB, and analysed for markers of inflammation, apoptosis and carcinogenesis.

RESULTS

Skin photosensitivity following exposure to UVA and UVB remained unchanged from baseline to 15-day follow-up in both groups (UVA change HCT 0.0 J/cm 2 vs. placebo 0.0 J/cm 2 ; P  = 0.99; UVB change HCT 0.0 J/cm 2 vs. placebo -0.2 J/cm 2 ; P  = 0.06). Pyrimidine dimers were not detected in either group. In vitro , combination of HCT and UVB irradiation did not induce the expression of oxidative stress marker proteins, inflammatory proteins, apoptotic proteins or activation of oncoproteins.

CONCLUSION

HCT did not increase photosensitivity for UVA or UVB in healthy volunteers compared with placebo, and was not associated with phototoxic or carcinogenic reactions. In vitro , HCT was also not associated with phototoxicity or carcinogenesis (NCT04654312).

Targeting oxidative stress as a preventive and therapeutic approach for cardiovascular disease

Cardiovascular diseases (CVDs) continue to exert a significant impact on global mortality rates, encompassing conditions like pulmonary arterial hypertension (PAH), atherosclerosis (AS), and myocardial infarction (MI). Oxidative stress (OS) plays a crucial role in the pathogenesis and advancement of CVDs, highlighting its significance as a contributing factor. Maintaining an equilibrium between reactive oxygen species (ROS) and antioxidant systems not only aids in mitigating oxidative stress but also confers protective benefits on cardiac health. Herbal monomers can inhibit OS in CVDs by activating multiple signaling pathways, such as increasing the activity of endogenous antioxidant systems and decreasing the level of ROS expression. Given the actions of herbal monomers to significantly protect the normal function of the heart and reduce the damage caused by OS to the organism. Hence, it is imperative to recognize the significance of herbal monomers as prospective therapeutic interventions for mitigating oxidative damage in CVDs. This paper aims to comprehensively review the origins and mechanisms underlying OS, elucidate the intricate association between CVDs and OS, and explore the therapeutic potential of antioxidant treatment utilizing herbal monomers. Furthermore, particular emphasis will be placed on examining the cardioprotective effects of herbal monomers by evaluating their impact on cardiac signaling pathways subsequent to treatment.

Cathepsins in the extracellular space: Focusing on non-lysosomal proteolytic functions with clinical implications

Cathepsins can be found in the extracellular space, cytoplasm, and nucleus. It was initially suspected that the primary physiological function of the cathepsins was to break down intracellular protein, and that they also had a role in pathological processes including inflammation and apoptosis. However, the many actions of cathepsins outside the cell and their complicated biological impacts have garnered much interest. Cathepsins play significant roles in a number of illnesses by regulating parenchymal cell proliferation, cell migration, viral invasion, inflammation, and immunological responses through extracellular matrix remodeling, signaling disruption, leukocyte recruitment, and cell adhesion. In this review, we outline the physiological roles of cathepsins in the extracellular space, the crucial pathological functions performed by cathepsins in illnesses, and the recent breakthroughs in the detection and therapy of specific inhibitors and fluorescent probes in associated dysfunction.

Cardiac copper content and its relationship with heart physiology: Insights based on quantitative genetic and functional analyses using BXD family mice

Background

Copper (Cu) is essential for the functioning of various enzymes involved in important cellular and physiological processes. Although critical for normal cardiac function, excessive accumulation, or deficiency of Cu in the myocardium is detrimental to the heart. Fluctuations in cardiac Cu content have been shown to cause cardiac pathologies and imbalance in systemic Cu metabolism. However, the genetic basis underlying cardiac Cu levels and their effects on heart traits remain to be understood. Representing the largest murine genetic reference population, BXD strains have been widely used to explore genotype-phenotype associations and identify quantitative trait loci (QTL) and candidate genes.

Methods

Cardiac Cu concentration and heart function in BXD strains were measured, followed by QTL mapping. The candidate genes modulating Cu homeostasis in mice hearts were identified using a multi-criteria scoring/filtering approach.

Results

Significant correlations were identified between cardiac Cu concentration and left ventricular (LV) internal diameter and volumes at end-diastole and end-systole, demonstrating that the BXDs with higher cardiac Cu levels have larger LV chamber. Conversely, cardiac Cu levels negatively correlated with LV posterior wall thickness, suggesting that lower Cu concentration in the heart is associated with LV hypertrophy. Genetic mapping identified six QTLs containing a total of 217 genes, which were further narrowed down to 21 genes that showed a significant association with cardiac Cu content in mice. Among those, Prex1 and Irx3 are the strongest candidates involved in cardiac Cu modulation.

Conclusion

Cardiac Cu level is significantly correlated with heart chamber size and hypertrophy phenotypes in BXD mice, while being regulated by multiple genes in several QTLs. Prex1 and Irx3 may be involved in modulating Cu metabolism and its downstream effects and warrant further experimental and functional validations.

Identification of the prognostic, diagnostic, and biological significance of the miR-148a-3p/cathepsin A axis in hepatocellular carcinoma

A comprehensive analysis of the prognostic, diagnostic, and biological significance of miR-148a-3p and cathepsin A (CTSA) in hepatocellular carcinoma (HCC) was performed using bioinformatics algorithms with The Cancer Genome Atlas (TCGA) data. miR-148a-3p and CTSA gene expression in HCC tissues and nontumor specimens was analyzed using TCGA database with R software. CTSA staining analysis was validated using the Human Protein Atlas database. Prognostic, diagnostic, gene set enrichment, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and immune infiltration analyses were implemented using the TCGA database with R software. Based on TCGA data and our cohort populations, CTSA expression was significantly elevated in HCC tissues compared with nontumor specimens. A significant negative correlation between miR-148a-3p and CTSA was observed in the TCGA data and our cohort population. Mechanistically, CTSA was a direct gene target of miR-148a-3p. Both CTSA and miR-148a-3p could serve as prognostic and diagnostic indicators in HCC. miR-148a-3p expression was significantly and negatively correlated with the StromalScore, ImmuneScore, and ESTIMATEScore in patients with liver cancer. miR-148a-3p mimic-mediated apoptosis and the inhibition of HCC cell growth and migration were counteracted by CTSA overexpression. The miR-148a-3p/CTSA axis was implicated in immune cell infiltration and carcinogenesis of HCC. miR-148a-3p and CTSA might be prospective molecular targets to enhance the potency of immunotherapy in HCC.

In Silico Structural Analysis of Serine Carboxypeptidase Nf314, a Potential Drug Target in Naegleria fowleri Infections

Naegleria fowleri, also known as the “brain-eating” amoeba, is a free-living protozoan that resides in freshwater bodies. This pathogenic amoeba infects humans as a casual event when swimming in contaminated water. Upon inhalation, N. fowleri invades the central nervous system and causes primary amoebic meningoencephalitis (PAM), a rapidly progressive and often fatal disease. Although PAM is considered rare, reducing its case fatality rate compels the search for pathogen-specific proteins with a structure–function relationship that favors their application as targets for discovering new or improved drugs against N. fowleri infections. Herein, we report a computational approach to study the structural features of Nf314 (a serine carboxypeptidase that is a virulence-related protein in N. fowleri infections) and assess its potential as a drug target, using bioinformatics tools and in silico molecular docking experiments. Our findings suggest that Nf314 has a ligand binding site suitable for the structure-based design of specific inhibitors. This study represents a further step toward postulating a reliable therapeutic target to treat PAM with drugs specifically aimed at blocking the pathogen proliferation by inhibiting protein function.