Inhibition of cathepsin B activity prevents deterioration in the quality of in vitro aged porcine oocytes

Cathepsin L regulates oocyte meiosis and preimplantation embryo development

Early embryonic loss, caused by reduced embryo developmental competence, is the major cause of subfertility in humans and animals. This embryo developmental competence is determined during oocyte maturation and the first embryo divisions. Therefore, it is essential to identify the underlying molecules regulating these critical developmental stages. Cathepsin L (CTSL), a lysosomal cysteine protease, is involved in regulating cell cycle progression, proliferation and invasion of different cell types. However, CTSL role in mammalian embryo development is unknown. Using bovine in vitro maturation and culture systems, we show that CTSL is a key regulator for embryo developmental competence. We employed a specific CTSL detection assay in live cells to show that CTSL activity correlates with meiotic progression and early embryo development. Inhibiting CTSL activity during oocyte maturation or early embryo development significantly impaired oocyte and embryo developmental competence as evidenced by lower cleavage, blastocyst and hatched blastocyst rates. Moreover, enhancing CTSL activity, using recombinant CTSL (rCTSL), during oocyte maturation or early embryo development significantly improved oocyte and embryo developmental competence. Importantly, rCTSL supplementation during oocyte maturation and early embryo development significantly improved the developmental competence of heat-shocked oocytes/embryos which are notoriously known for reduced quality. Altogether, these results provide novel evidence that CTSL plays a pivotal role in regulating oocyte meiosis and early embryonic development.

Elucidation of chemical profiles and molecular targets of Mondia whitei leave fractions bioactive as novel therapeutics: an in vitro and in silico assay

BACKGROUND

Mondia whitei root is often used in Africa as a local therapeutic agent for libido enhancement. The fractions of the M. whitei leaves (MWL) lack chemical characterization of their bioactive components and possible molecular targets. We characterized and investigated its molecular target as therapeutic agents in an in vitro and in silico assay. Mineral compositions, antioxidant, and GC-MS characterization were studied. The cytotoxicity effect was measured on HeLa and HT-29 cells by MTT assay. In silico potential inhibitors of Cathepsin B (CathB) as a cancer biomarker were determined.

RESULTS

The flame photometry produced marked Na⁺ and K⁺. GC-MS revealed eighteen bioactive components. The fractions (chloroformic 47.00, ethanolic 45.52, and aqueous 40.13) of MWL caused a higher inhibition ratio compared to standards. The MWL showed a significant cytotoxic effect on the treated cell lines at concentrations of 150 and 200 μg/ml and 100, 150, and 200 μg/ml for HT-29 and HeLa cells, respectively. Ten bioactives (MWL 4, 5, 6, 8, 9, 10, 14, 15, 17, and 18) showed potential inhibition of CathB with binding affinities of -4.40 to -8.3 Kcal/Mol. However, MWL 4, 9, 14, and 17 which have higher binding affinities (-6.7, -7.1, -8.2, and -8.3, respectively) than the standard inhibitor (-6.5) were the lead molecules.

CONCLUSION

These chemical profiles and potential molecular targets unraveled in this study propose that MWL has a promising anticancer activity.

Citrinin impairs pig oocyte maturation by inducing oxidative stress and apoptosis

Citrinin (CTN) is a polyketide mycotoxin produced by several strains of Penicillium, Monascus, and Aspergillus. While CTN poses various toxic effects on the female reproductive system in animals, its direct effects on germ cell development are unclear. This study aimed to evaluate the effects of increasing concentrations of CTN (0,20,40,80,100 μM) on porcine oocyte in vitro maturation. Our results indicate that CTN supplementation inhibited polar body extrusion in a dose-dependent manner. Actin and spindle assembly were also disrupted after treatment, indicating that CTN affects the cytoskeleton of porcine oocytes. Oxidative stress and apoptosis were observed under CTN treatment to explore the cause of meiotic maturation failure in porcine oocytes. The results showed that reactive oxygen species levels, cathepsin B activity, and caspase-3 activity were increased in the treated group, indicating that CTN induced oxidative stress and apoptosis. In conclusion, CTN exposure could reduce porcine oocyte maturation by affecting cytoskeletal dynamics, oxidative stress, and apoptosis.

Inhibitory effects of astaxanthin on postovulatory porcine oocyte aging in vitro

Mammalian oocytes represent impaired quality after undergoing a process of postovulatory aging, which can be alleviated through various effective ways such as reagent treatment. Accumulating evidences have revealed the beneficial effects of astaxanthin (Ax) as a potential antioxidant on reproductive biology. Here, porcine matured oocytes were used as a model to explore whether Ax supplement can protect against oocyte aging in vitro and the underlying mechanism, and therefore they were cultured with or without 2.5 μM Ax for an additional 24 h. Aged oocytes treated with Ax showed improved yield and quality of blastocysts as well as recovered expression of maternal genes. Importantly, oxidative stress in aged oocytes was relieved through Ax treatment, based on reduced reactive oxygen species and enhanced glutathione and antioxidant gene expression. Moreover, inhibition in apoptosis and autophagy of aged oocyte by Ax was confirmed through decreased caspase-3, cathepsin B and autophagic activities. Ax could also maintain spindle organization and actin expression, and rescue functional status of organelles including mitochondria, endoplasmic reticulum, Golgi apparatus and lysosomes according to restored fluorescence intensity. In conclusion, Ax might provide an alternative for ameliorating the oocyte quality following aging in vitro, through the mechanisms mediated by its antioxidant properties.

Cathepsin B aggravated doxorubicin‑induced myocardial injury via NF‑κB signalling

Myocyte apoptosis and oxidative stress key critical roles in the process of doxorubicin (DOX)-induced cardiotoxicity. However, how apoptosis and oxidative stress arise in DOX-induced heart injury remains largely unknown. Cathepsin B (CTSB) is a typical lysosomal cysteine protease that is associated with apoptosis, inflammatory responses, oxidative stress and autophagy. The present study aimed to investigate the role of CTSB in DOX-induced heart injury and its potential mechanism. H9C2 cells were infected with adenovirus or transfected with small interfering RNA to overexpress or knock down CTSB, respectively, and then stimulated with DOX. DOX induced increased CTSB expression levels in H9C2 cells. DOX-induced cardiomyocyte apoptosis and oxidative stress were attenuated by CTSB knockdown but aggravated by CTSB overexpression in vitro. Mechanistically, the present study showed that CTSB activated the NF-κB pathway in response to DOX. In summary, CTSB aggravated DOX-induced H9C2 cell apoptosis and oxidative stress via NF-κB signalling. CTSB constitutes a potential therapeutic target for the treatment of DOX-induced cardiotoxicity.