Improper protein trafficking contributes to artemisinin sensitivity in cells lacking the KDAC Rpd3p

Lysine deacetylases (KDACs) inhibitors may have therapeutic value in anti-malarial combination therapies with artemisinin. To evaluate connections between KDACs and artemisinin, Saccharomyces cerevisiae deletion mutants in KDAC genes were assayed. Deletion of RPD3, but not other KDAC genes, resulted in strong sensitivity to artemisinin, which was also observed in sit4Δ mutants with impaired endoplasmic reticulum (ER) to Golgi protein trafficking. Decreased accumulation of the transporters Pdr5p, Fur4p, and Tat2p was observed in rpd3Δ and sit4Δ cells. The unfolded protein response is induced in rpd3Δ cells consistent with retention of proteins in the ER. Disruption of protein trafficking appears to sensitize cells to artemisinin and targeting these pathways may be useful as part of artemisinin based anti-malarial therapy.     

Sequence variation in CYP51A from the Y strain of Trypanosoma cruzi alters its sensitivity to inhibition

CYP51 (sterol 14α-demethylase) is an efficient target for clinical and agricultural antifungals and an emerging target for treatment of Chagas disease, the infection that is caused by multiple strains of a protozoan pathogen Trypanosoma cruzi. Here, we analyze CYP51A from the Y strain T. cruzi. In this protein, proline 355, a residue highly conserved across the CYP51 family, is replaced with serine. The purified enzyme retains its catalytic activity, yet has been found less susceptible to inhibition. These biochemical data are consistent with cellular experiments, both in insect and human stages of the pathogen. Comparative structural analysis of CYP51 complexes with VNI and two derivatives suggests that broad-spectrum CYP51 inhibitors are likely to be preferable as antichagasic drug candidates.     

Sex and exercise interact to alter the expression of anabolic androgenic steroid-induced anxiety-like behaviors in the mouse

Anabolic androgenic steroids (AAS) are taken by both sexes to enhance athletic performance and body image, nearly always in conjunction with an exercise regime. Although taken to improve physical attributes, chronic AAS use can promote negative behavior, including anxiety. Few studies have directly compared the impact of AAS use in males versus females or assessed the interaction of exercise and AAS. We show that AAS increase anxiety-like behaviors in female but not male mice and that voluntary exercise accentuates these sex-specific differences. We also show that levels of the anxiogenic peptide corticotrophin releasing factor (CRF) are significantly greater in males, but that AAS selectively increase CRF levels in females, thus abrogating this sex-specific difference. Exercise did not ameliorate AAS-induced anxiety or alter CRF levels in females. Exercise was anxiolytic in males, but this behavioral outcome did not correlate with CRF levels. Brain-derived neurotrophic factor (BDNF) has also been implicated in the expression of anxiety. As with CRF, levels of hippocampal BDNF mRNA were significantly greater in males than females. AAS and exercise were without effect on BDNF mRNA in females. In males, anxiolytic effects of exercise correlated with increased BDNF mRNA, however AAS-induced changes in BDNF mRNA and anxiety did not. In sum, we find that AAS elicit sex-specific differences in anxiety and that voluntary exercise accentuates these differences. In addition, our data suggest that these behavioral outcomes may reflect convergent actions of AAS and exercise on a sexually differentiated CRF signaling system within the extended amygdala.     

Otoacoustic emissions,auditory evoked potentials and self-reported gender in people affected by disorders of sex development (DSD)

Both otoacoustic emissions (OAEs) and auditory evoked potentials (AEPs) are sexually dimorphic, and both are believed to be influenced by prenatal androgen exposure. OAEs and AEPs were collected from people affected by 1 of 3 categories of disorders of sex development (DSD) — (1) women with complete androgen insensitivity syndrome (CAIS); (2) women with congenital adrenal hyperplasia (CAH); and (3) individuals with 46,XY DSD including prenatal androgen exposure who developed a male gender despite initial rearing as females (men with DSD). Gender identity (GI) and role (GR) were measured both retrospectively and at the time of study participation, using standardized questionnaires. The main objective of this study was to determine if patterns of OAEs and AEPs correlate with gender in people affected by DSD and in controls. A second objective was to assess if OAE and AEP patterns differed according to degrees of prenatal androgen exposure across groups. Control males, men with DSD, and women with CAH produced fewer spontaneous OAEs (SOAEs) – the male-typical pattern – than control females and women with CAIS. Additionally, the number of SOAEs produced correlated with gender development across all groups tested. Although some sex differences in AEPs were observed between control males and females, AEP measures did not correlate with gender development, nor did they vary according to degrees of prenatal androgen exposure, among people with DSD. Thus, OAEs, but not AEPs, may prove useful as bioassays for assessing early brain exposure to androgens and predicting gender development in people with DSD.     

Relationship between 22-kHz calls and testosterone in male rats

Ultrasonic calls in rats induced by the presence of a predator, referred to as “22-kHz calls,” are mainly emitted by socially dominant male rats. Testosterone levels are closely related to social dominance in male rats. In the present study, we investigated the relationship between the emission of stress-induced 22-kHz calls and circulating testosterone levels in male rats, using a combination of surgery (castration or sham operation) and chronic steroid administration (testosterone or cholesterol) to modify circulating testosterone levels. We also assessed the effects of androgen and/or estrogen receptor antagonists on the emission of 22-kHz calls in male rats. An air puff stimulus, known to reliably induce 22-kHz calls in rats, was used as a stressor. Castrated rats with cholesterol implants exhibited significantly fewer 22-kHz calls than rats that had received a sham operation and cholesterol implants, and there was no significant difference between castrated rats with testosterone implants and rats that had received a sham operation and cholesterol implants. Only male rats pretreated with a binary mixture of androgen and estrogen antagonists exhibited significantly fewer 22-kHz calls than controls. These results show that testosterone in male rats has a positive effect on the emission of stress-induced 22-kHz calls, and the calls may be regulated by the activation of both androgen and estrogen receptors.     

First evidence of pathogenicity of V234I mutation of hVAPB found in Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis is a motor neurodegenerative disease which is characterized by progressive loss of motor neurons followed by paralysis and eventually death. In human, VAMP-associated protein B (VAPB) is the causative gene of the familial form of ALS8. Previous studies have shown that P56S and T46I point mutations of hVAPB are present in this form of ALS. Recently, another mutation, V234I of hVAPB was found in one familial case of ALS. This is the first study where we have shown that V234I-VAPB does not form aggregate like other two mutants of VAPB and localizes differently than the wild type VAPB. It induces Ubiquitin aggregation followed by cell death. We propose that V234I-VAPB exhibits the characteristics of ALS in spite of not having the typical aggregation property of different mutations in various neurodegenerative diseases.