Altered expression of mitofusin 2 in penile tissues of diabetic rats

Combination of resveratrol and 5-azacytydine improves osteogenesis of metabolic syndrome mesenchymal stem cells

Endocrine disorders have become more and more frequently diagnosed in humans and animals. In horses, equine metabolic syndrome (EMS) is characterized by insulin resistance, hyperleptinemia, hyperinsulinemia, inflammation and usually by pathological obesity. Due to an increased inflammatory response in the adipose tissue, cytophysiological properties of adipose derived stem cells (ASC) have been impaired, which strongly limits their therapeutic potential. Excessive accumulation of reactive oxygen species, mitochondria deterioration and accelerated ageing of those cells affect their multipotency and restrict the effectiveness of the differentiation process. In the present study, we have treated ASC isolated from EMS individuals with a combination of 5-azacytydine (AZA) and resveratrol (RES) in order to reverse their aged phenotype and enhance osteogenic differentiation. Using SEM and confocal microscope, cell morphology, matrix mineralization and mitochondrial dynamics were assessed. Furthermore, we investigated the expression of osteogenic-related genes with RT-PCR. We also investigated the role of autophagy during differentiation and silenced PARKIN expression with siRNA. Obtained results indicated that AZA/RES significantly enhanced early osteogenesis of ASC derived from EMS animals. Increased matrix mineralization, RUNX-2, collagen type I and osteopontin levels were noted. Furthermore, we proved that AZA/RES exerts its beneficial effects by modulating autophagy and mitochondrial dynamics through PARKIN and RUNX-2 activity.

Expression of mitofusin 2 in human sperm and its relationship to sperm motility and cryoprotective potentials

Mitofusin 2 is a kind of mitochondria membrane protein that has been implicated in maintenance of mitochondrial morphology and function. However, the expression and function of mitofusin 2 in human sperm are not well described at present. The aim of this study was to explore the location of mitofusin 2 in human sperm and to discover its relationship to human sperm functions like motility and cryoprotective potentials. Our result showed that mitofusin 2 is specifically localized in the 5-7 μm midpiece between the neck and main part of human sperm tail. The expression level of mitofusin 2 in human sperm was significantly different between the normozoospermia and asthenozoospermia groups ( P < 0.05); meanwhile, the sperm of the asthenozoospermia group had a lower mitochondrial membrane potential ( P < 0.05), but the results of TUNEL assay did not show significant difference between the two groups. Furthermore, we found that the expression level of mitofusin 2 in the freeze-resistant group (cryo-survival rate >40%) was significantly higher than that of the freeze-intolerant group (cryo-survival rate ≤40%) ( P < 0.05). These results demonstrate that the expression level of mitofusin 2 is related to motility and cryoprotective potentials of human sperm. Mitofusin 2 may play a crucial role in the function of human sperm, which needs further research to discover the mechanism. Impact statement The exact function of mitochondria in human sperm before and during fertilization process remains controversial. MFN2 is a kind of mitochondria membrane protein and participates in the regulation of mitochondrial morphology and function. In this study, we discover the relationship of MFN2 expression to human sperm motility and cryoprotective potentials. Our results suggest that MFN2 could be a new target for the mechanism research of asthenozoospermia. MFN2 may also serve as a protein marker predicting the ability of human sperm to sustain cryopreservation.

Human tissue kallikrein 1 ameliorates erectile function via modulation of macroautophagy in aged transgenic rats

Previously, we have demonstrated that human tissue kallikrein 1 (hKLK1) improves age-related erectile dysfunction (ED). Autophagy has been implicated in age-related diseases, including ED. However, the molecular mechanisms underlying hKLK1-mediated amelioration of age-related ED via regulation of autophagy remains unknown. To explore the potential mechanism, male wild-type Sprague-Dawley rats (WTR) and transgenic rats harboring human KLK1 (TGR) were bred till 4 or 18 months of age and divided into three groups: young WTR (yWTR) as the control group, aged WTR (aWTR) group, and aged TGR (aTGR) group. The erectile function of each rat was evaluated using cavernous nerve electrostimulation. The ratio of intracavernous pressure/mean arterial pressure (ICP/MAP) and total ICP were also measured. Western blotting, immunohistochemistry, and transmission electron microscopy were performed to detect the levels of autophagy. The expression levels of related signaling pathways were determined by western blotting and immunohistochemistry. We found that hKLK1 improved the impaired erectile function of aged rats. Compared to the yWTR and aTGR groups, the aWTR group showed reduced smooth muscle/collagen ratio, fewer autophagosomes, and lower expression of Beclin 1 and LC3-II, which indicate impaired smooth muscle function and low level of autophagy in the smooth muscle cells. Moreover, the PI3K/Akt/mTOR signaling pathway, which is considered to be a negative regulator of autophagy, was upregulated in the aWTR group. hKLK1 may partially restore erectile function in aged transgenic rats by upregulating protective autophagy via the PI3K/Akt/mTOR pathway. These observations indicate that hKLK1 is a potential gene therapy candidate for age-related ED.

Reduced corporal fibrosis to protect erectile function by inhibiting the Rho-kinase/LIM-kinase/cofilin pathway in the aged transgenic rat harboring human tissue kallikrein 1

Our previous studies have demonstrated that erectile function was preserved in aged transgenic rats (TGR) harboring the human tissue kallikrein 1 (hKLK1), while the molecular level of hKLK1 on corporal fibrosis to inhibit age-related erectile dysfunction (ED) is poorly understood. Male wild-type Sprague-Dawley rats (WTR) and TGR harboring the hKLK1 gene were fed to 4- or 18-month-old and divided into three groups: young WTR (yWTR) as the control, aged WTR (aWTR), and aged TGR (aTGR). Erectile function of all rats was assessed by cavernous nerve electrostimulation method. Masson's trichrome staining was used to evaluate corporal fibrosis in the corpus cavernosum. We found that the erectile function of rats in the aWTR group was significantly lower than that of other two groups. Masson's trichrome staining revealed that compared with those of the yWTR and aTGR groups, the ratio of smooth muscle cell (SMC)/collagen (C) was significantly lower in the aWTR group. Immunohistochemistry and Western blotting analysis were performed, and results demonstrated that expression of α-SMA was lower, while expressions of transforming growth factor-β 1 (TGF-β1), RhoA, ROCK1, p-MYPT1, p-LIMK2, and p-cofilin were higher in the aWTR group compared with those in other two groups. However, LIMK2 and cofilin expressions did not differ among three groups. Taken together, these results indicated that the RhoA/ROCK1/LIMK/cofilin pathway may be involved in the corporal fibrosis caused by advanced age, and hKLK1 may reduce this corporal fibrosis by inhibiting the activation of this pathway to ameliorate age-related ED.

Involvement of DDAH/ADMA/NOS/cGMP and COX-2/PTGIS/cAMP Pathways in Human Tissue Kallikrein 1 Protecting Erectile Function in Aged Rats

Our previous studies had reported that Human Tissue Kallikrein 1 (hKLK1) preserved erectile function in aged transgenic rats, while the detailed mechanism of hKLK1 protecting erectile function in aged rats through activation of cGMP and cAMP was not mentioned. To explore the latent mechanism, male wild-type Sprague-Dawley rats (WTR) and transgenic rats harboring the hKLK1 gene (TGR) were fed to 4 and 18 months old and divided into four groups: young WTR (yWTR) as the control, aged WTR (aWTR), aged TGR (aTGR) and aged TGRs with HOE140 (aTGRH). Erectile function of all rats was evaluated by cavernous nerve electrostimulation method and measured by the ratio of intracavernous pressure/ mean arterial pressure (ICP/MAP) in rats. Expression levels of cAMP and cGMP were assessed, and related signaling pathways were detected by western blot, immunohistochemistry and RT-PCR. Our experiment results showed erectile function of the aWTR group and aTGRH group was lower compared with those of other two groups. Also, expression levels of cAMP and cGMP were significantly lower than those of other two groups. Moreover, expressions of related signaling pathways including DDAH/ADMA/NOS/cGMP and COX-2/PTGIS/cAMP were also downregulated in the corpus cavernosum of rats in aWTR group. Our finding revealed hKLK1 played a protective role in age-related ED. The DDAH/ADMA/NOS/cGMP and COX-2/PTGIS/cAMP pathways that were linked to the mechanism hKLK1 could increase the levels of cGMP and cAMP, which might provide novel therapy targets for age-related ED.