Autophagy, an evolutionarily conserved cell reprogramming mechanism, exists in all eukaryotic organisms. It is a fundamental and vital degradation/recycling pathway that removes undesirable components, such as cytoplasmic organelles, misfolded proteins, viruses, and intracellular bacteria, to provide energy and essential materials for organisms. The success of male reproduction depends on healthy testes, which are mainly composed of seminiferous tubules and mesenchyme. Seminiferous tubules are composed of Sertoli cells (SCs) and various germ cells, and the main functional part of mesenchyme are Leydig cells (LCs). In recent years, a large amount of evidence has confirmed that autophagy is active in many cellular events associated with the testes. Autophagy is not only important for testicular spermatogenesis, but is also an essential regulatory mechanism for the ectoplasmic specialization (ES) integrity of SCs, as well as for the normal function of the blood–testes barrier (BTB). At the same time, it is active in LCs and is crucial for steroid production and for maintaining testosterone levels. In this review, we expanded upon the narration regarding the composition of the testes; summarized the regulation and molecular mechanism of autophagy in SCs, germ cells, and LCs; and concluded the roles of autophagy in the process of spermatogenesis and testicular endocrinology. Through integrating the latest summaries and advances, we discuss how the role of autophagy is a double-edged sword in the testes and may provide insight for future studies and explorations on autophagy in male reproduction.

Porcine deltacoronavirus (PDCoV) is an emerging porcine enteric coronavirus causing significant economic losses to the pig farming industry globally. In this study, we expressed the S protein of a highly virulent PDCoV strain in the CHO eukaryotic expression system. After immunizing alpaca with the PDCoV S protein and employing the phage display library technique, a high-affinity and specific nanobody Nb3 against PDCoV S protein was successfully established by three rounds of biopanning and a phage enzyme-linked immunosorbent assay (ELISA). Furthermore, a competitive ELISA (cELISA) was developed based on Nb3 to rapidly and efficiently detect PDCoV antibody levels. The cELISA displayed no cross-reaction with positive sera of porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine rotavirus (PoRV), pseudorabies virus (PRV), classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), or porcine circovirus 2 (PCV2), thereby showing good specificity. The cELISA successfully detected positive sera diluted 1:127 (percentage inhibition ≥ 50.02%), indicating high sensitivity. Both the intra- and inter-batch coefficients of variation were less than 10%, indicating good repeatability. The cELISA had a total coincidence rate of 98.33% with the indirect immunofluorescence assay and a significant positive correlation with the virus neutralization test ( r = 0.861, P < 0.001), suggesting that the cELISA can be used to measure the neutralizing antibody titers in serum samples. In conclusion, our nanobody-based cELISA showed good performance indicators and can be used to monitor and evaluate antibody levels following clinical infection of PDCoV or vaccine immunization. IMPORTANCE: This study screened out a high-affinity and specific nanobody Nb3 against porcine deltacoronavirus (PDCoV) S protein and established a nanobody-based competitive ELISA (cELISA) for PDCoV antibody detection. This cELISA is a simple, rapid, and specific method that can effectively measure the neutralizing antibody titers in serum samples.

Telocytes (TCs) are a newly discovered type of mesenchymal cell that are closely related to the tissue’s internal environment. The study aimed to investigate the morphological identification of TCs in the epididymis of adult yak and their role in the local microenvironment. In this study, transmission electron microscopy (TEM), scanning electron microscopy, immunofluorescence, qRT-PCR, and western blotting were used to analyze the cell morphology of TCs. The results showed that there are two types of TCs in the epididymal stroma of yak by TEM; one type is distributed around the capillaries with full cell bodies, longer TPs, and a large number of secretory vesicles; the other is distributed outside the basement membrane with irregularly long, striped, large nuclei and short telopodes (TPs). In addition, these TCs formed complex TC cell networks through TPs with epididymal interstitial capillaries and basal fibroblasts. TCs often appear near the capillaries and basement membrane by special staining. The surface markers of TCs (CD34, vimentin, and CD117) were positively expressed in the epididymal stroma and epithelium by immunohistochemistry, and immunofluorescence co-expression of vimentin + CD34 and CD117 + CD34 was observed on the surface of TCs. The trends in the mRNA and protein expression of TCs surface markers revealed expression was highest in the caput epididymis. In summary, this is first report of TCs in the epididymis of yak, and two phenotypes of TCs were observed. The existence and distribution characteristics of TCs in the epididymis of plateau yaks provide important clues for further study of the adaptation to reproductive function in the plateau.