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Background: Astaxanthin (ATX) is a carotenoid pigment with pleiotropic pharmacological properties that is seen as a possible drug for treating cerebral ischemic injury and subarachnoid hemorrhage. Na+-K+-2Cl- co-transporter-1 (NKCC1), an intrinsic membrane protein expressed by many cell types, is activated by various insults, leading to the formation of cell swelling and brain edema. We previously established that ATX attenuated brain edema and improved neurological outcomes by modulating NKCC1 expression after traumatic brain injury in mice. This paper explored the molecular mechanism of ATX-mediated inhibition of NKCC1 utilizing an in vitro astrocyte stretch injury model.Results: Stretch injury in cultured astrocytes lowered cell viability time-dependently, which was substantially reducing by pretreating with ATX (50 μmol/L). Stretch injury increased Bax level and cleaved caspase-3 activity, and decreased Bcl-2 level and pro-caspase 3 activity, resulting in the apoptosis of astrocytes. Additionally, stretch injury substantially raised the gene and protein expressions of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α and prompted the expression and nuclear translocation of NF-κB. Pretreatment with ATX remarkably prevented the trauma-induced initiation of NF-κB, expressions of pro-inflammatory cytokines, and cell apoptosis. Moreover, stretch injury markedly elevated the gene and protein expression of NKCC1, which was partly blocked by co-treatment with ATX (50 µmol/L) or an NF-κB inhibitor (PDTC, 10 µmol/L). Cleaved caspase-3 activity was partially reduced by PDTC (10 µmol/L) or an NKCC1 inhibitor (bumetanide, 50 µmol/L).Conclusions: ATX attenuates apoptosis after stretch injury in cultured astrocytes by inhibiting NKCC1 expression, and it acts by reducing the expression of NF-κB-mediated pro-inflammatory factors. [ABSTRACT FROM AUTHOR]

Background: Apoptosis is important for regulating spermatogenesis. The protein mRHBDD1 (mouse homolog of human RHBDD1)/rRHBDD1 (rat homolog of human RHBDD1) is highly expressed in the testis and is involved in apoptosis of spermatogonia. GC-1, a spermatogonia cell line, has the capacity to differentiate into spermatids within the seminiferous tubules. We constructed mRHBDD1 knockdown GC-1 cells and evaluated their capacity to differentiate into spermatids in mouse seminiferous tubules. Results: Stable mRHBDD1 knockdown GC-1 cells were sensitive to apoptotic stimuli, PS341 and UV irradiation. In vitro, they survived and proliferated normally. However, they lost the ability to survive and differentiate in mouse seminiferous tubules. Conclusion: Our findings suggest that mRHBDD1 may be associated with mammalian spermatogenesis. [ABSTRACT FROM AUTHOR]

Aim: To explore the anticancer effects and the molecular mechanisms of gambogic acid (GA) on Jurkat cells. Methods: Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Annexin V-fluorescein-isothiocyanate/propidium iodide, DNA defragmentation, and comet assay were used to detect apoptosis. Western blotting was used to study the expression of death inducer-obliterator-1 (DIO-1), Bcl-2, NF-κB, and procaspase 3, as well as 2 activated subunits: p17 and p20. The subcellular localization of DIO-1 was examined by immunofluorescence and Hoechst33258 staining. Results: GA inhibited the proliferation of Jurkat cells with 50% inhibitory concentration values of 1.51±0.09 (24 h), 0.98±0.13 (48 h), and 0.67±0.12 μmol/L (72 h). GA was able to induce apoptosis of Jurkat cells. Treated by GA, the expression of DIO-1 was upregulated, and that of Bcl-2 and NF-κB was downregulated, leading to the activation of pro-caspase 3. GA induced the translocation of DIO-1 to the nucleus. Conclusion: GA suppressed the proliferation of Jurkat cells by apoptosis induction. DIO-1 triggered early-stage cell death in GA-treated Jurkat cells. [ABSTRACT FROM AUTHOR]