17ß-Oestradiol Attenuates the Photoreceptor Apoptosis in Mice with Retinitis Pigmentosa by Regulating N-myc Downstream Regulated Gene 2 Expression.

Retinitis pigmentosa (RP) is a heterogeneous group of retinal degenerative diseases in which the final pathological feature is photoreceptor cell apoptosis. Currently, the pathogenesis of RP remains poorly understood and therapeutics are ineffective. 17ß-Oestradiol (ßE2) is universally acknowledged as a neuroprotective factor in neurodegenerative diseases and has manifested neuroprotective effects in a light-induced retinal degeneration model. Recently, we identified N-myc downstream regulated gene 2 (NDRG2) suppression as a molecular marker of mouse retinal photoreceptor-specific cell death. ßE2 has also been reported to regulate NDRG2 in salivary acinar cells. Therefore, in this study, we investigated whether ßE2 plays a protective role in RP and regulates NDRG2 in photoreceptor cells. To this end, we generated RP models and observed that ßE2 not only reduced the apoptosis of photoreceptor cells, but also restored the level of NDRG2 expression in RP models. Then, we showed that siNDRG2 inhibits the anti-apoptotic effect of ßE2 on photoreceptor cells in a cellular RP model. Subsequently, we used a classic oestrogen receptor (ER) antagonist to attenuate the effects of ßE2, suggesting that ßE2 exerted its effects on RP models via the classic ERs. In addition, we performed a bioinformatics analysis, and the results indicated that the reported oestrogen response element (ERE) sequence is present in the promoter region of the mouse NDRG2 gene. Overall, our results suggest that ßE2 attenuated the apoptosis of photoreceptor cells in RP models by maintaining NDRG2 expression via a classic ER-mediated mechanism.

Photoreceptor protection by mesenchymal stem cell transplantation identifies exosomal MiR-21 as a therapeutic for retinal degeneration.

Photoreceptor apoptosis is recognized as one key pathogenesis of retinal degeneration, the counteraction of which represents a promising approach to safeguard visual function. Recently, mesenchymal stem cell transplantation (MSCT) has demonstrated immense potential to treat ocular disorders, in which extracellular vesicles (EVs), particularly exosomes, have emerged as effective ophthalmological therapeutics. However, whether and how MSCT protects photoreceptors against apoptotic injuries remains largely unknown. Here, we discovered that intravitreal MSCT counteracted photoreceptor apoptosis and alleviated retinal morphological and functional degeneration in a mouse model of photoreceptor loss induced by N-methyl-N-nitrosourea (MNU). Interestingly, effects of MSCT were inhibited after blockade of exosomal generation by GW4869 preconditioning. Furthermore, MSC-derived exosomal transplantation (EXOT) effectively suppressed MNU-provoked photoreceptor injury. Notably, therapeutic efficacy of MSCT and EXOT on MNU-induced retinal degeneration was long-lasting as photoreceptor preservance and retinal maintenance were detected even after 1-2 months post to injection for only once. More importantly, using a natural occurring retinal degeneration model caused by a nonsense mutation of Phosphodiesterase 6b gene (Pde6bmut), we confirmed that MSCT and EXOT prevented photoreceptor loss and protected long-term retinal function. In deciphering therapeutic mechanisms regarding potential exosome-mediated communications, we identified that miR-21 critically maintained photoreceptor viability against MNU injury by targeting programmed cell death 4 (Pdcd4) and was transferred from MSC-derived exosomes in vivo for functional regulation. Moreover, miR-21 deficiency aggravated MNU-driven retinal injury and was restrained by EXOT. Further experiments revealed that miR-21 mediated therapeutic effects of EXOT on MNU-induced photoreceptor apoptosis and retinal dysfunction. These findings uncovered the efficacy and mechanism of MSCT-based photoreceptor protection, indicating exosomal miR-21 as a therapeutic for retinal degeneration.

Hydroxychloroquine Blocks Autophagy and Promotes Apoptosis of the Prostate after Castration in Rats.

Autophagy is an important pro-survival mechanism and closely related to apoptosis. The aim of this study was to investigate whether hydroxychloroquine (HCQ) blocks autophagy and promotes apoptosis of the prostate after castration. METHODS: Thirty-six male SD rats were randomly divided into 3 groups (n = 12): control group (sham operation), castration group, and HCQ group (castrated and treated with HCQ). On day 7, all mice were executed and prostates were isolated. The morphological changes of prostates were observed by light microscope, and the ultrastructure changes were observed under scanning electron microscope (SEM). The protein expression of Beclin-l, P62, caspase-3, Bcl-2, and Bax was assessed by immunohistochemical analyses. The mRNA expression of microtubule-associated protein light chain 3 (LC3) and autophagy-related gene 5 (Atg5) was detected by RT-PCR. RESULTS: Prostates of castration group shrank remarkably and prostates of HCQ group shrank more remarkably than castration group. Cytolysosomes were visible in the prostates of the castration group under SEM. Immunohistochemistry showed that the protein of Beclin-1 increased in the castration group compared to the control group, while decreased in the HCQ group compared to the castration group. While P62 protein moderately dyed in the control group and weakly dyed in the castration group, it strongly dyed in the HCQ group. Caspase-3 and Bax protein were weakly dyed in the control group but moderately dyed in the castration group and strongly dyed in the HCQ group. The expressions of apoptosis suppressor Bcl-2 were reduced in the castration group and further reduced in the HCQ group compared to the castration group. RT-PCR revealed that the mRNA of LC3 and Atg5 in the castration group increased compared to the control group, while decreased after treated with HCQ. CONCLUSION: Autophagy increased after castrated in prostates, while decreased after treated with HCQ; all these indicated that HCQ blocked autophagy and then promoted prostate apoptosis of castrated mice.

Bone progeria diminished the therapeutic effects of bone marrow mesenchymal stem cells on retinal degeneration.

Senescence is closely related to the occurrence of retinal degeneration. Recent studies have shown that bone marrow mesenchymal stem cells (BMMSCs) have significant therapeutic effects on retinal degeneration, While BMMSCs suffer from functional decline in bone aging. Whether senescence affects BMMSCs therapy on retinal degeneration remains unknown. Here, we applied the previously established bone progeria animal model, the senescence-accelerated mice-prone 6 (SAMP6) strain, and surprisingly discovered that SAMP6 mice demonstrated retinal degeneration at 6 months old. Furthermore, BMMSCs derived from SAMP6 mice failed to prevent MNU-induced retinal degeneration in vivo. As expected, BMMSCs from SAMP6 mice exhibited impairment in the differentiation capacities, compared to those from the age-matched senescence-accelerated mice-resistant 1 (SAMR1) strain. Moreover, BMMSCs from SAMR1 mice counteracted MNU-induced retinal degeneration, with increased expression of the retina survival hallmark, N-myc downstream regulated gene 2 (NDRG2). Taken together, these findings reveal that bone progeria diminished the therapeutic effects of BMMSC on retinal degeneration.

Decreased expression of matrix metalloproteinase-1 in the maternal umbilical serum, trophoblasts and decidua leads to preeclampsia.

The aim of the present study was to explore the levels of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the maternal umbilical serum, placenta and decidua of patients with preeclampsia compared with those in normotensive pregnant females. A total of 73 pregnant females were recruited as the test subjects, including 43 inpatients with hypertensive disorders in pregnancy and 30 normal pregnant females as the control. The 43 inpatients with hypertensive disorders in pregnancy included 18 patients with gestational hypertension, nine with mild preeclampsia and 16 with severe preeclampsia. MMP-1 and TIMP-1 ELISA kits were used to determine the MMP-1 and TIMP-1 levels in the umbilical serum of the parturient following delivery. MMP-1 and TIMP-1 expressed in the placenta and decidua of the parturient following delivery were evaluated using immunohistochemistry. MMP-1 and TIMP-1 were mainly located in cytotrophoblasts and syncytiotrophoblasts in the placenta and decidua. The levels of MMP-1 in the umbilical serum of the normal, gestational hypertension, mild preeclampsia and severe preeclampsia groups were 294.33±11.53, 247.78±20.32, 177.67±12.63 and 124.68±15.41 pg/ml, respectively, and there were significant differences between each two groups (P<0.05). The positive expression rate of MMP-1 in the placenta and decidua of patients with hypertensive disorders in pregnancy was lower than that of the controls (P<0.01 and P<0.01, respectively). However, no significant difference was identified between each two groups with regard to the levels of TIMP-1 in the umbilical cord and the positive rates in the placenta and decidua (P>0.05). Reduced MMP-1 levels in the umbilical serum, placenta and decidua were observed in women who developed preeclampsia.