ABSTRACT
As a pivotal player in spermatogenesis, the blood-testis barrier (BTB) made from junction apparatus coexisting in Sertoli cells (SCs) is impaired with an increase in age and ultimately induces spermatogenic dysfunction or even infertility. It has been corroborated that bone marrow mesenchymal stem cell (BMSC) transplantation can efficiently repair and regenerate the testicular function. As vital mediators of cell-to-cell communication, MSC-derived exosomes (Exos) can directly serve as therapeutic agents for tissue repair and regeneration. However, the therapeutic value of BMSC-Exos in aging-induced BTB damage remains to be confirmed. In this study, we explored that the old porcine testes had defective autophagy, which aggravated BTB disruption in SCs. BMSC-Exos could decrease ROS production and NLRP3 inflammasome activation but enhanced autophagy and tight junction (TJ) function in D-gal-triggered aging porcine SCs and mouse model testes, according to in vitro and in vivo experiments. Furthermore, rapamycin, NAC, MCC950, and IL-1Ra restored the TJ function in D-gal-stimulated aging porcine SCs, while BMSC-Exos' stimulatory effect on TJ function was inhibited by chloroquine. Moreover, the treatment with BMSC-Exos enhanced autophagy in D-gal-induced aging porcine SCs by means of the AMPK/mTOR signal transduction pathway. These findings uncovered through the present study that BMSC-Exos can enhance the BTB function in aging testes by improving autophagy via the AMPK/mTOR signaling pathway, thereby suppressing ROS production and NLRP3 inflammasome activation.
ABSTRACT
The functionalized ligand 9,10-anthraquinone-1,4-dicarboxylate acid (H2AQDC) was designed and synthesized in order to develop metal-organic coordination polymers as heterogeneous catalysts with a photosensitizing feature. Two major considerations of the ligand design are anthraquinone moieties for photosensitizing to harvest light and carboxylate groups for polymeric coordination toward less solubility. A series of transition metal complexes based on this ligand were synthesized subsequently, namely {Co(AQDC)(H2O)3·2H2O}n (Co-AQDC), {Ni(AQDC)(H2O)3·2H2O}n (Ni-AQDC), {[Cu(AQDC)(H2O)3][Cu(AQDC)(H2O)2(DMF)]·(H2O)4}n (Cu-AQDC), {Zn1.5(AQDC)(OH)(H2O)2·H2O}n (Zn-AQDC), {Ag2(AQDC)(CH3OH)}n (Ag-AQDC). Both the ligand and its transition metal complexes are able to catalyze the visible-light driven oxidation reactions of alkynes into 1,2-diketones in air under mild conditions, in which compound Ni-AQDC demonstrates the best activity. This catalyst can be easily isolated from the reaction mixture by filtration with a trace amount of loss in solution and is ready for recycled use after simple washing and drying without any need for regeneration. Remarkably, the catalyst shows no loss of activity after five catalytic cycles and X-ray powder diffraction proves no change in the structure after five runs. This designed metal-organic coordination polymer represents an environmentally friendly, economical and recyclable photocatalyst, constituting a good candidate for photocatalytic organic syntheses in terms of green chemistry.
