Alcohol and aging - An area of increasing concern.

Alcohol use is increasing among adults 65 and older and the size of this population is expanding rapidly. Aging is associated with systemic inflammation, sleep disturbances, cancers, cognitive decline, and increased risk of injury and death from falls and other accidents. Alcohol misuse exacerbates and accelerates these age-related changes. Older drinkers are more sensitive to acute alcohol-induced impairments in memory, coordination, reaction time, and driving performance. Oxidative stress and DNA damage resulting from chronic heavy alcohol consumption contribute to an increased risk of cancer, liver disease, and cardiovascular disease. Medication use increases with age and many medications prescribed to older adults can interact negatively with alcohol. The rapid expansion of the population aged 65 and older, combined with higher levels of alcohol use and AUD in the Baby Boomer cohort than the preceding generation, could significantly increase the burden of alcohol on the healthcare system resulting from AUD and alcohol-related injuries and diseases. Screening and brief intervention for hazardous alcohol use among older patients along with education regarding potential interactions between alcohol and medications could substantially reduce the risk of harms from alcohol but currently is underutilized.

A new synonymy in the genus Macrocixius (Hemiptera: Fulgoromorpha: Cixiidae).

Until recently the genus Macrocixius Matsumura, 1914 (Hemiptera: Fulgoromorpha: Cixiidae) contained two species: M. giganteus Matsumura, 1914 (the type species) and M. grossus Tsaur & Hsu, 1991. Two recent papers revised the genus within a short interval of time. Both Zhang & Chen (2013) and Orosz (2013) provided redescriptions of the genus and its two previously included species; Zhang & Chen (2013) described two new species from China; Orosz (2013) described five new species from Nepal, Taiwan, Vietnam, and Indonesia.

HSPB2 is dispensable for the cardiac hypertrophic response but reduces mitochondrial energetics following pressure overload in mice.

BACKGROUND: CryAB (HspB5) and HspB2, two small heat shock genes located adjacently in the vertebrate genome, are hypothesized to play distinct roles. Mice lacking both cryab and hspb2 (DKO) are viable and exhibit adult-onset degeneration of skeletal muscle but confounding results from independent groups were reported for cardiac responses to different stressful conditions (i.e., ischemia/reperfusion or pressure overload). To determine the specific requirements of HSPB2 in heart, we generated cardiac-specific HSPB2 deficient (HSPB2cKO) mice and examined their cardiac function under basal conditions and following cardiac pressure overload. METHODOLOGY/PRINCIPAL FINDINGS: Transverse aortic constriction (TAC) or sham surgery was performed in HSPB2cKO mice and their littermates (HSPB2wt mice). Eight weeks after TAC, we found that expression of several small HSPs (HSPB2, 5, 6) was not markedly modified in HSPB2wt mice. Both cardiac function and the hypertrophic response remained similar in HSPB2cKO and HSPB2wt hearts. In addition, mitochondrial respiration and ATP production assays demonstrated that the absence of HSPB2 did not change mitochondrial metabolism in basal conditions. However, fatty acid supported state 3 respiration rate (ADP stimulated) in TAC operated HSPB2cKO hearts was significantly reduced in compared with TAC operated HSPB2wt mice (10.5±2.2 vs. 12.8±2.5 nmol O(2)/min/mg dry fiber weight, P<0.05), and ATP production in HSPB2cKO hearts was significantly reduced in TAC compared with sham operated mice (29.8±0.2 vs. 21.1±1.8 nmol ATP/min/mg dry fiber weight, P<0.05). Although HSPB2 was not associated with mitochondria under cardiac stress, absence of HSPB2 led to changes in transcript levels of several metabolic and mitochondrial regulator genes. CONCLUSIONS/SIGNIFICANCE: The present study indicates that HSPB2 can be replaced by other members of the multigene small HSP family under basal conditions while HSPB2 is implicated in the regulation of metabolic/mitochondrial function under cardiac stress such pressure overload.

Selective degradation of aggregate-prone CryAB mutants by HSPB1 is mediated by ubiquitin-proteasome pathways.

Disease-causing mutations of genes encoding small MW heat shock proteins (sHSPs) constitute a growing family of inherited myofibrillar disorders. In the present work, we found that three structurally-distinct CryAB mutants R120G, 450delA and 464delCT are mostly present in the detergent-insoluble fractions when overexpressed in H9c2 rat heart cells. We found that either over-expression or knockdown of HSPB1, a related sHSP, affects the solubility, stability, and degradation of aggregation-prone CryAB mutants. HSPB1 overexpression has negligible effects on the solubility and protein aggregates of either R120G and/or 450delA but increased the solubility and prevented formation of 464delCT aggregates. HSPB1 knockdown decreased solubility and increased protein aggregates of all CryAB mutants, indicating a key role for HSPB1 in clearance of CryAB mutants under basal conditions. We provide four lines of evidence that such selective clearance of R120G, 450delA and 464delCT mutants by HSPB1 is mediated by the ubiquitin-proteasome system (UPS). First, we found that treatment with the proteasome inhibitors increased the levels of all CryAB mutants. Second, R120G and 450delA overexpression corresponded to the accumulation of their specific ubiquitin conjugates in H9c2 cells. Third, HSPB1 knockdown directly increased the levels of all polyubiquitin conjugates. And fourth, the selective attenuation of 464delCT expression by HSPB1 over-expression was abrogated by the proteasome inhibition. We conclude that such selective interactions between CryAB mutants and HSPB1 overexpression might have important implications for the clinical manifestations and potential treatment.

A FOXA1-binding enhancer regulates Hoxb13 expression in the prostate gland.

Hoxb13 is robustly transcribed in derivatives of posterior endoderm including the colon, rectum, and the prostate gland. Transcriptional activity in the prostate persists unabated under conditions of androgen deprivation and throughout the course of disease progression in a mouse prostate cancer model. To elucidate the molecular basis of prostate-restricted transcriptional activation of Hoxb13, a bacterial artificial chromosome (BAC)-based reporter gene deletion analysis was performed in transgenic mice. Two regions downstream of the Hoxb13 coding region were found to be required to support transcriptional activity in the prostate but were completely dispensable for expression in the colon and rectum. Bioinformatic analyses of one region identified a 37-bp element conserved in mammals. This element, which bears two potential binding sites for Forkhead class transcription factors, is occupied by FOXA1 in a human prostate cancer cell line. Precise replacement of this enhancer with an extended LoxP site in the context of a 218,555-bp BAC reporter nearly extinguished Hoxb13-mediated transcriptional activity in the mouse prostate. These data demonstrate that FOXA1 directly regulates HOXB13 in human prostate epithelial cells, and show that this prostate-specific regulatory mechanism is conserved in mice.

Inhibition of CREB function in mouse epidermis reduces papilloma formation.

We used a double transgenic tetracycline system to conditionally express A-CREB, a dominant negative protein that prevents the DNA binding and function of cAMP-responsive element binding protein (CREB) family members, in mouse basal epidermis using the keratin 5 promoter. There was no phenotype in the adult. However, following a 7,12-dimethylbenz(a)anthracene (DMBA)/phorbol-12-myristate-13-acetate two-stage skin carcinogenesis experiment, A-CREB-expressing epidermis develop 5-fold fewer papillomas than wild-type controls. However, A-CREB expression one month after DMBA treatment does not prevent papilloma formation, suggesting that CREB functions at an early stage of papilloma formation. Oncogenic H-Ras genes with A-->T mutations in codon 61 were found in wild-type skin but not in A-CREB-expressing skin 2 days after DMBA treatment, suggesting that A-CREB either prevents DMBA mutagenesis or kills oncogenic H-Ras cells. In primary keratinocyte cultures, A-CREB expression induced apoptosis of v-Ras(Ha)-infected cells and suppressed the expression of cell cycle proteins cyclin B1 and cyclin D1. These results suggest that inhibiting CREB function is a valuable cancer prevention strategy.

Human alpha B-crystallin mutation causes oxido-reductive stress and protein aggregation cardiomyopathy in mice.

The autosomal dominant mutation in the human alphaB-crystallin gene inducing a R120G amino acid exchange causes a multisystem, protein aggregation disease including cardiomyopathy. The pathogenesis of cardiomyopathy in this mutant (hR120GCryAB) is poorly understood. Here, we show that transgenic mice overexpressing cardiac-specific hR120GCryAB recapitulate the cardiomyopathy in humans and find that the mice are under reductive stress. The myopathic hearts show an increased recycling of oxidized glutathione (GSSG) to reduced glutathione (GSH), which is due to the augmented expression and enzymatic activities of glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase, and glutathione peroxidase. The intercross of hR120GCryAB cardiomyopathic animals with mice with reduced G6PD levels rescues the progeny from cardiac hypertrophy and protein aggregation. These findings demonstrate that dysregulation of G6PD activity is necessary and sufficient for maladaptive reductive stress and suggest a novel therapeutic target for abrogating R120GCryAB cardiomyopathy and heart failure in humans.

Inhibition of CCAAT/enhancer binding protein family DNA binding in mouse epidermis prevents and regresses papillomas.

The CCAAT/enhancer binding proteins (C/EBP) are a family of B-ZIP DNA binding proteins that act as transcription factors to regulate growth and differentiation of many cell types, including keratinocytes. To examine the consequences of inhibiting the C/EBP family of transcription factors in skin, we generated transgenic mice that use the tetracycline system to conditionally express A-C/EBP, a dominant negative that inhibits the DNA binding of C/EBP family members. We expressed A-C/EBP in the basal layer of the skin epidermis during a two-step skin carcinogenesis protocol. A-C/EBP expression caused hyperplasia of the basal epidermis and increased apoptosis in the suprabasal epidermis. The mice developed fewer papillomas and had systemic hair loss. A-C/EBP expression caused C/EBPbeta protein to disappear whereas C/EBPalpha, p53, Bax, and caspase-3 protein levels were dramatically up-regulated in the suprabasal layer. Primary keratinocytes recapitulate the A-C/EBP induction of cell growth and increase in p53 protein. A-C/EBP expression after papilloma development caused the papillomas to regress with an associated increase in apoptosis and up-regulation of p53 protein. Furthermore, A-C/EBP-expressing mice heterozygous for p53 were more susceptible to papilloma formation, suggesting that the suppression of papilloma formation has a p53-dependent mechanism. These results implicate DNA binding of C/EBP family members as a potential molecular therapeutic target.

A search for candidate genes for lipodystrophy, obesity and diabetes via gene expression analysis of A-ZIP/F-1 mice.

Genome scans for diabetes have identified many regions of the human genome that correlate with the disease state. To identify candidate genes for type 2 diabetes, we examined the transgenic A-ZIP/F-1 mouse. This mouse model has no white fat, resulting in abnormal levels of glucose, insulin, and leptin, making the A-ZIP/F-1 mice a good model for lipodystrophy and insulin resistance. We used cDNA-based microarrays to find differentially expressed genes in four tissues of these mice. We examined these results in the context of human linkage scans for lipodystrophy, obesity, and type 2 diabetes. We combined 199 known human orthologs of the misregulated mouse genes with 33 published human genome scans on a genome map. Integrating expression data with human linkage results permitted us to suggest and prioritize candidate genes for lipodystrophy and related disorders. These genes include a cluster of 3 S100A genes on chromosome 1 and SLPI1 on chromosome 20.