HIV-1 Vpr-Induced Apoptosis Is Cell Cycle Dependent and Requires Bax but Not ANT

The HIV-1 accessory protein viral protein R (Vpr) causes G(2) arrest and apoptosis in infected cells. We previously identified the DNA damage–signaling protein ATR as the cellular factor that mediates Vpr-induced G(2) arrest and apoptosis. Here, we examine the mechanism of induction of apoptosis by Vpr and how it relates to induction of G(2) arrest. We find that entry into G(2) is a requirement for Vpr to induce apoptosis. We investigated the role of the mitochondrial permeability transition pore by knockdown of its essential component, the adenine nucleotide translocator. We found that Vpr-induced apoptosis was unaffected by knockdown of ANT. Instead, apoptosis is triggered through a different mitochondrial pore protein, Bax. In support of the idea that checkpoint activation and apoptosis induction are functionally linked, we show that Bax activation by Vpr was ablated when ATR or GADD45α was knocked down. Certain mutants of Vpr, such as R77Q and I74A, identified in long-term nonprogressors, have been proposed to inefficiently induce apoptosis while activating the G(2) checkpoint in a normal manner. We tested the in vitro phenotypes of these mutants and found that their abilities to induce apoptosis and G(2) arrest are indistinguishable from those of HIV-1(NL4–3) vpr, providing additional support to the idea that G(2) arrest and apoptosis induction are mechanistically linked

Increased gonadotrophin stimulation does not improve IVF outcomes in patients with predicted poor ovarian reserve

The original publication can be found at www.springerlink.comPurpose This retrospective study was carried out to evaluate whether increasing the starting dose of FSH stimulation above the standard dose of 150 IU/day in patients with low predicted ovarian reserve can improve IVF outcomes. Method A total of 122 women aged less than 36 years in their first cycle of IVF were identified as having likely low ovarian reserve based on a serum AMH measurement below 14 pmol/l. Thirty five women were administered the standard dose of 150 IU/day FSH, while the remaining 87 received a higher starting dose (200–300 IU/day FSH). There were no significant differences in age, BMI, antral follicle count, serum AMH, FSH or aetiology of infertility between the two dose groups. Results No significant improvement in oocyte and embryo yield or pregnancy rates was observed following an upward adjustment of FSH starting dose. While increasing the dose of FSH above 150 IU/day did not produce any adverse events such as OHSS, it did consume an extra 1,100 IU of FSH per IVF cycle. Conclusion The upward FSH dose adjustment in anticipation of low ovarian reserve can not be advocated as it is both expensive and of no proven clinical value.Dharmawijaya N Lekamge, Michelle Lane, Robert B Gilchrist and Kelton P Tremelle

Modulation of lipopolysaccharide-induced neuronal response by activation of the enteric nervous system.

International audienceBackground:Evidence continues to mount concerning the importance of the enteric nervous system (ENS) incontrolling numerous intestinal functions in addition to motility and epithelial functions. Nevertheless, little isknown concerning the direct participation of the ENS in the inflammatory response of the gut during infectious orinflammatory insults. In the present study we analyzed the ENS response to bacterial lipopolysaccharide, inparticular the production of a major proinflammatory cytokine, tumor necrosis factor-alpha (TNF-α).Methods:TNF-αexpression (measured by qPCR, quantitative Polymerase Chain Reaction) and production(measured by ELISA) were measured in human longitudinal muscle-myenteric plexus (LMMP) and rat ENS primarycultures (rENSpc). They were either treated or not treated with lipopolysaccharide (LPS) in the presence or not ofelectrical field stimulation (EFS). Activation of extracellular signal-regulated kinase (ERK) and 5?-adenosinemonophosphate-activated protein kinase (AMPK) pathways was analyzed by immunocytochemistry and Westernblot analysis. Their implications were studied using specific inhibitors (U0126, mitogen-activated protein kinasekinase, MEK, inhibitor and C compound, AMPK inhibitor). We also analyzed toll-like receptor 2 (TLR2) expression andinterleukin-6 (IL-6) production after LPS treatment simultaneously with EFS or TNF-α-neutralizing antibody.Results:Treatment of human LMMP or rENSpc with LPS induced an increase in TNF-αproduction. Activation of theENS by EFS significantly inhibited TNF-αproduction. This regulation occurred at the transcriptional level. Signalinganalyses showed that LPS induced activation of ERK but not AMPK, which was constitutively activated in rENSpcneurons. Both U0126 and C compound almost completely prevented LPS-induced TNF-αproduction. In the presenceof LPS, EFS inhibited the ERK and AMPK pathways. In addition, we demonstrated using TNF-α-neutralizing antibody thatLPS-induced TNF-αproduction increased TLR2 expression and reduced IL-6 production.Conclusions:Our results show that LPS induced TNF-αproduction by enteric neurons through activation of thecanonical ERK pathway and also in an AMPK-dependent manner. ENS activation through the inhibition of thesepathways decreased TNF-αproduction, thereby modulating the inflammatory response induced by endotoxin