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Objective: Brown adipose tissue (BAT) plays a crucial role in regulating non-shivering thermogenesis under cold exposure. Proline hydroxylases (PHDs) were found to be involved in adipocyte differentiation and lipid deposition. However, the effects of PHDs on regulatory mechanisms of BAT thermogenesis are not fully understood. Methods: We detected the expression of PHDs in different adipose tissues by using immunoblotting and real-time PCR. Further, immunoblotting, real-time PCR, and immunostaining were performed to determine the correlation between proline hydroxylase 2 (PHD2) and UCP1 expression. Inhibitor of PHDs and PHD2-sgRNA viruses were used to construct the PHD2-deficiency model in vivo and in vitro to investigate the impacts of PHD2 on BAT thermogenesis. Afterward, the interaction between UCP1 and PHD2 and the hydroxylation modification level of UCP1 were verified by Co-IP assays and immunoblotting. Finally, the effect of specific proline hydroxylation on the expression/activity of UCP1 was further confirmed by site-directed mutation of UCP1 and mass spectrometry analysis. Results: PHD2, but not PHD1 and PHD3, was highly enriched in BAT, colocalized, and positively correlated with UCP1. Inhibition or knockdown of PHD2 significantly suppressed BAT thermogenesis under cold exposure and aggravated obesity of mice fed HFD. Mechanistically, mitochondrial PHD2 bound to UCP1 and regulated the hydroxylation level of UCP1, which was enhanced by thermogenic activation and attenuated by PHD2 knockdown. Furthermore, PHD2-dependent hydroxylation of UCP1 promoted the expression and stability of UCP1 protein. Mutation of the specific prolines (Pro-33, 133, and 232) in UCP1 significantly mitigated the PHD2-elevated UCP1 hydroxylation level and reversed the PHD2-increased UCP1 stability. Conclusions: This study suggested an important role for PHD2 in BAT thermogenesis regulation by enhancing the hydroxylation of UCP1.

Nutritional diarrhea and subsequent performance degradation in weaned piglets are major challenges for the pig industry. Bile acids (BA) can be added to the diet as emulsifiers. This experiment was conducted to investigate the effects of chenodeoxycholic acid (CDCA), a major primary BA, on growth performance, serum metabolic profiles and gut health in weaned piglets. A total of 72 healthy weaned piglets were randomly assigned to the control (CON) and the CDCA groups, which were feed a basal diet and the basal diet supplemented with 200 mg/kg CDCA for 30 d, respectively. Our results demonstrated that CDCA significantly increased final BW and average daily gain (ADG), decreased feed-to-gain (F:G) ratio and tended to reduce diarrhea incidence. In addition, CDCA increased the villus height-to-crypt depth (V:C) ratio, elevated goblet cell numbers and the expression of tight junction proteins, suggesting the enhancement of intestinal barrier function. As an emulsifier, CDCA increased jejunal lipase activity and the mRNA expression of pancreatic lipases. CDCA supplementation also altered the serum metabolic profiles, including increasing the levels of indole 3-acetic acid, N′-formylkynurenine and theobromine that were beneficial for gut health. Moreover, the relative abundance of 2 beneficial gut bacteria, Prevotella 9 and Prevotellaceae TCG-001, were increased, whereas the relative abundance of a harmful bacteria, Dorea, was decreased in the gut of weaned piglets supplemented with CDCA. Importantly, the altered serum metabolic profiles showed a strong correlation with the changed gut bacteria. In conclusion, CDCA improved the growth performance of weaned piglets by improving intestinal morphology and barrier function, and enhancing lipid digestion, accompanied by alterations of serum metabolic profiles, and changes in relative abundance of certain gut bacteria.

Abstract Background Although many reports show that various kinds of stem cells have the ability to recover function in premature ovarian aging, few studies have looked at stem cell treatment of natural ovarian aging (NOA). We designed this experimental study to investigate whether human amniotic mesenchymal stem cells (hAMSCs) retain the ability to restore ovarian function, and how hAMSCs work in this process. Methods To build the NOA mouse model, the mice were fed for 12–14 months normally with young fertile female mice as the normal control group (3–5 months old). Hematoxylin and eosin staining permitted follicle counting and showed the ovarian tissue structure. An enzyme-linked immunosorbent assay was used to detect the serum levels of the sex hormones estradiol (E2), anti-mullerian hormone (AMH), and follicle-stimulating hormone (FSH). The proliferation rate and marker expression level of human ovarian granule cells (hGCs) (ki67, AMH, FSH receptor, FOXL2, and CYP19A1) were measured by flow cytometry (FACS). Cytokines (growth factors) were measured by a protein antibody array methodology. After hepatocyte growth factor (HGF) and epidermal growth factor (EGF) were co-cultured with hGCs, proliferation (ki67) and apoptosis (Annexin V) levels were analyzed by FACS. After HGF and EGF were injected into the ovaries of natural aging mice, the total follicle numbers and hormone levels were tested. Results After the hAMSCs were transplanted into the NOA mouse model, the hAMSCs exerted a therapeutic activity on mouse ovarian function by improving the follicle numbers over four stages. In addition, our results showed that hAMSCs significantly promoted the proliferation rate and marker expression level of ovarian granular cells that were from NOA patients. Meanwhile, we found that the secretion level of EGF and HGF from hAMSCs was higher than other growth factors. A growth factor combination (HGF with EGF) improved the proliferation rate and inhibited the apoptosis rate more powerfully after a co-culture with hGCs, and total follicle numbers and hormone levels were elevated to a normal level after the growth factor combination was injected into the ovaries of the NOA mouse model. Conclusions These findings provide insight into the notion that hAMSCs play an integral role in resistance to NOA. Furthermore, our present study demonstrates that a growth factor combination derived from hAMSCs plays a central role in inhibiting ovarian aging. Therefore, we suggest that hAMSCs improve ovarian function in natural aging by secreting HGF and EGF.