Denatonium Benzoate-Induces Oxidative Stress in the Heart and Kidney of Chinese Fast Yellow Chickens by Regulating Apoptosis, Autophagy, Antioxidative Activities and Bitter Taste Receptor Gene Expressions

G protein-coupled receptor-mediated autophagy in health and disease

G protein-coupled receptors (GPCRs) constitute the largest and most diverse superfamily of mammalian transmembrane proteins. These receptors are involved in a wide range of physiological functions and are targets for more than a third of available drugs in the market. Autophagy is a cellular process involved in degrading damaged proteins and organelles and in recycling cellular components. Deficiencies in autophagy are involved in a variety of pathological conditions. Both GPCRs and autophagy are essential in preserving homeostasis and cell survival. There is emerging evidence suggesting that GPCRs are direct regulators of autophagy. Additionally, autophagic machinery is involved in the regulation of GPCR signalling. The interplay between GPCR and autophagic signalling mechanisms significantly impacts on health and disease; however, there is still an incomplete understanding of the underlying mechanisms and therapeutic implications in different tissues and disease contexts. This review aims to discuss the interactions between GPCR and autophagy signalling. Studies on muscarinic receptors, beta-adrenoceptors, taste receptors, purinergic receptors and adhesion GPCRs are summarized, in relation to autophagy.

Cellular mechanisms and molecular pathways linking bitter taste receptor signalling to cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases

Heart diseases and related complications constitute a leading cause of death and socioeconomic threat worldwide. Despite intense efforts and research on the pathogenetic mechanisms of these diseases, the underlying cellular and molecular mechanisms are yet to be completely understood. Several lines of evidence indicate a critical role of inflammatory and oxidative stress responses in the development and progression of heart diseases. Nevertheless, the molecular machinery that drives cardiac inflammation and oxidative stress is not completely known. Recent data suggest an important role of cardiac bitter taste receptors (TAS2Rs) in the pathogenetic mechanism of heart diseases. Independent groups of researchers have demonstrated a central role of TAS2Rs in mediating inflammatory, oxidative stress responses, autophagy, impulse generation/propagation and contractile activities in the heart, suggesting that dysfunctional TAS2R signalling may predispose to cardiac inflammatory and oxidative stress disorders, characterised by contractile dysfunction and arrhythmia. Moreover, cardiac TAS2Rs act as gateway surveillance units that monitor and detect toxigenic or pathogenic molecules, including microbial components, and initiate responses that ultimately culminate in protection of the host against the aggression. Unfortunately, however, the molecular mechanisms that link TAS2R sensing of the cardiac milieu to inflammatory and oxidative stress responses are not clearly known. Therefore, we sought to review the possible role of TAS2R signalling in the pathophysiology of cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases. Potential therapeutic significance of targeting TAS2R or its downstream signalling molecules in cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction is also discussed.

Freeze-Dried Royal Jelly Proteins Enhanced the Testicular Development and Spermatogenesis in Pubescent Male Mice

Simple Summary

Spermatogenesis and hormones secretions are serious life-threating and complicated process, which can be improve through science-based approaches. Royal jelly is a thick white milky fluid secreted by the hypopharyngeal and mandibular glands of young nurse worker bees (Apis mellifera) and used to feed their queen to expand their life. The results of the study revealed that, the growth performance of testis in exposed mice to freeze-dried Royal Jelly for 35 consecutive days were significantly enhanced in moderate dose among other treated doses. However, at Post Natal Days (PNDs 14 and PNDs 21), obviously changes were observed in histological examination of the testis while at PNDs-07 no major changes were observed. The Tunnel assay showed that, less apoptotic cells were detected in the testis of mice in high dose of freeze-dried RJ and oral administration of freeze-dried royal jelly can aggravate adverse effects via tempestuous on sexual hormone secretion at both PNDs 21 and PNDs 35 respectively.

Abstract

Spermatogenesis and hormones secretions are crucial endocrine and physiological process for maintaining the life. Royal Jelly (RJ) bioactive components are Major Royal Jelly Proteins (MRJPs), owing exceptional biological properties. However, the effects of RJ on pup’s testicular development during neonatal and pubertal period exposure hasn’t been adequately studied. The aim of the study was to detect neonatal sexual hormones concentration and histopathological changes on testicular development of the male progeny after oral exposure to freeze-dried RJ for 35 consecutive days. After mice give birth, male pups were collected together, separated by sex, and randomly standardized to seven (7) male pups per dam. Male pups were assigned to control diet (CON group), low dose RJ (L-RJ group) diet (control diet + 125 mg/kg/day RJ), moderate dose RJ (M-RJ group) diet (control diet + 250 mg/kg/day RJ) and high dose of RJ (H-RJ group) diet (control diet + 500 mg/kg/day RJ). After weaning, male pups were continuously fed with freeze-dried RJ until the age of PNDs 35. The results revealed that, oral M-RJ (250 mg/kg/day) administration significantly (p < 0.05) increased the testis weight, the diameter of seminiferous tubule and the height of seminiferous epithelium of offspring mice at PNDs 14. However, high-dose RJ (500 mg/kg/day) decreased the diameter of seminiferous tubule but increased the height of seminiferous epithelium of male offspring (p < 0.05) at the same time point. Furthermore, oral M-RJ treatment significantly (p < 0.05) increased the testis weight and spermatogenesis at PNDs 21. Whereas, oral H-RJ treatment significantly (p < 0.05) reduced the diameter of seminiferous tubule and the height of seminiferous epithelium at PNDs 21. At PNDs 35, oral M-RJ treatment increased the testis weight, the diameter of seminiferous tubule and the level of FSH. While, high-dose of RJ reduced testis weight and size (diameter of seminiferous tubule and height of seminiferous epithelium), ratio of apoptotic germ cells and incomplete spermatogenesis collectively. In addition, sexual hormone secretions (FSH, LH, E2) were decreased after RJs treatment (L-RJ, M-RJ, H-RJ) at PNDs 21 respectively. In conclusion, the results concluded that oral administration of low and moderate doses of RJ could enhance the development of testis at neonate period until pubescent, whereas unfavorable adverse effects induced by high dose of RJ might remain.