Assessing cognitive decline in the aging brain: lessons from rodent and human studies

As life expectancy continues to increase worldwide, age-related dysfunction will largely impact our societies in the future. Aging is well established to promote the deterioration of cognitive function and is the primary risk factor for the development of prevalent neurological disorders. Even in the absence of dementia, age-related cognitive decline impacts specific types of memories and brain structures in humans and animal models. Despite this, preclinical and clinical studies that investigate age-related changes in brain physiology often use largely different methods, which hinders the translational potential of findings. This review seeks to integrate what is known about age-related changes in the brain with analogue cognitive tests used in humans and rodent studies, ranging from "pen and paper" tests to virtual-reality-based paradigms. Finally, we draw parallels between the behavior paradigms used in research compared to the enrollment into clinical trials that aim to study age-related cognitive decline.

Molecular characterization of cbfβ gene and identification of new transcription variants: implications for function

The CBFβ gene encodes a transcription factor that, in combination with CBFα (also called Runx, runt-related transcription factor) regulates expression of several target genes. CBFβ interacts with all Runx family members, such as RUNX2, a regulator of bone-related gene transcription that contains a conserved DNA-binding domain. CBFβ stimulates DNA binding of the Runt domain, and is essential for most of the known functions of RUNX2. A comparative analysis of the zebrafish cbfβ gene and protein, and of its orthologous identified homologous proteins in different species indicates a highly conserved function. We cloned eleven zebrafish cbfβ gene transcripts, one resulting in the known Cbfβ protein (with 187 aa), and three additional variants resulting from skipping exon 5a (resulting in a protein with 174 aa) or exon 5b (resulting in a protein with 201 aa), both observed for the first time in zebrafish, and a completely novel isoform containing both exon 5a and 5b (resulting in a protein with 188 aa). Functional analysis of these isoforms provides insight into their role in regulating gene transcription. From the other variants two are premature termination Cbfβ forms, while the others show in-frame exon-skipping causing changes in the Cbfβ domain that may affect its function.

Drug addiction is not an independent risk factor for oncogenic human papillomavirus infections or high-grade cervical intraepithelial neoplasia: case-control study nested within the Latin American Screening study cohort

Drug abuse (addiction) has been listed among the risk factors for human papillomavirus (HPV) infections, but no case-control studies exist to rule out sexual behaviour and other potential confounders. The aim of this study is to evaluate the role of drug addiction as an independent predictor of HR-HPV infections and (cervical intraepithelial neoplasia) CIN2+ in an age-matched case-control (1:4) study nested within the prospective Latin American Screening (LAMS) study cohort. All 109 women in the LAMS cohort (n = 12,114) reporting drug abuse/addiction were matched with four controls (n = 436) of non-abusers strictly by age. Conditional logistic regression analysis was used to estimate the co-variates of drug abuse, and the whole series (n = 545) was analysed for predictors of HR-HPV and CIN2+ using univariate and multivariate regression models. Oncogenic HPV infections were significantly (P = 0.019) more prevalent among abusers (37.7%) than in controls (21.9%), but there was no difference in high-grade squamous intraepithelial lesions (P = 0.180) or CIN2+ lesions (P = 0.201). In multivariate conditional logistic regression, number of lifetime sexual partners (P = 0.0001), ever smokers (P = 0.0001), non-use of OCs (P = 0.013), ever having sexually transmitted diseases (STD) (P = 0.041) and no previous Pap smear (P = 0.027) were independent co-variates of drug addiction. Drug abuse was not an independent risk factor of high-risk (HR)-HPV infection, which was significantly predicted by (1) age below 30 years (P = 0.045), (2) more than five lifetime sexual partners (P = 0.046) and (3) being current smoker (P = 0.0001). In multivariate model, only HR-HPV infection was an independent risk factor of CIN2+ (P = 0.031), with adjusted OR = 11.33 (95% CI 1.25–102.50). These data indicate that drug addiction is not an independent risk factor of either HR-HPV infections or CIN2+, but the increased prevalence of HR-HPV infections is explained by the high-risk sexual behaviour and smoking habits of these women.

Cardiac malformations, adrenal agenesis, neural crest defects and exencephaly in mice lacking Cited2, a new Tfap2 co-activator

The protein EP300 and its paralog CREBBP (CREB-binding protein) are ubiquitously expressed transcriptional co-activators and histone acetyl transferases. The gene EP300 is essential for normal cardiac and neural development, whereas CREBBP is essential for neurulation, hematopoietic differentiation, angiogenesis and skeletal and cardiac development. Mutations in CREBBP cause Rubinstein-Taybi syndrome, which is characterized by mental retardation, skeletal abnormalities and congenital cardiac defects. The CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2) binds EP300 and CREBBP with high affinity and regulates gene transcription. Here we show that Cited2-/- embryos die with cardiac malformations, adrenal agenesis, abnormal cranial ganglia and exencephaly. The cardiac defects include atrial and ventricular septal defects, overriding aorta, double-outlet right ventricle, persistent truncus arteriosus and right-sided aortic arches. We find increased apoptosis in the midbrain region and a marked reduction in ErbB3-expressing neural crest cells in mid-embryogenesis. We show that CITED2 interacts with and co-activates all isoforms of transcription factor AP-2 (TFAP2). Transactivation by TFAP2 isoforms is defective in Cited2-/- embryonic fibroblasts and is rescued by ectopically expressed CITED2. As certain Tfap2 isoforms are essential in neural crest, neural tube and cardiac development, we propose that abnormal embryogenesis in mice lacking Cited2 results, at least in part, from its role as a Tfap2 co-activator.

Type I interferon gene expression: differential expression of IFN-A genes induced by viruses and double-stranded RNA

The family of interferon regulatory transcription factors (IRF) participates in the virus-induced and dsRNA-stimulated transcriptional regulation of either type I IFN genes or a definite set of genes which can also be activated by IFN. In this review, we place emphasis on the role of IRF-3 that associates with the coactivators CBP and/or p300, together or not with IRF-7. These complexes bind to the PRDI, PRDI-like domains or to a number of ISRE sequences located in the promoter of these virus-inducible genes. We also discuss the involvement of the IRF-3-related complexes in the differential regulation of IFN-A genes.

Synergism between multiple virus-induced factor-binding elements involved in the differential expression of interferon A genes

Comparative transfection analysis of murine interferon A4 and interferon A11 promoter constructs transiently transfected in mouse L929 and human HeLa S3 cells infected with Newcastle disease virus showed that the second positive regulatory domain I-like domain (D motif), located between nucleotides -57 and -46 upstream of the transcription start site, contributes to the activation of virus-induced transcription of the interferon (IFN)-A4 gene promoter by cooperating with the positive regulatory domain I-like and TG-like domains previously described. Electrophoretic mobility shift assay performed with the virus-inducible fragments containing these motifs indicated that the binding activity that we have denoted as virus-induced factor (Génin, P., Bragança, J., Darracq, N., Doly, J., and Civas, A. (1995) Nucleic Acids Res. 23, 5055-5063) is different from interferon-stimulated gene factor 3. It binds to the D motif but not to the virus-unresponsive form of the D motif disrupted by a G-57 --> C substitution. We show that the low levels of IFN-A11 gene expression are caused essentially by the lack of two inducible enhancer domains disrupted by the A-78 --> G and the G-57 --> C substitutions. These data suggest a model taking account of the differential regulation of IFN-A gene family members. They also suggest that virus-induced factor may correspond to the primary transcription factor directly activated by virus that is involved in the initiation of IFN-A gene transcription.

A novel PRD I and TG binding activity involved in virus-induced transcription of IFN-A genes

Comparative analysis of the inducible elements of the mouse interferon A4 and A11 gene promoters (IE-A4 and IE-A11) by transient transfection experiments, DNase 1 footprinting and electrophoretic mobility shift assays resulted in identification of a virus-induced binding activity suggested to be involved in NDV-induced activation of transcription of these genes. The virus-induced factor, termed VIF, is activated early by contact of virions with cells. It specifically recognizes the PRD I-like domain shared by both inducible elements, as well as the TG-like domain of IE-A4. This factor, distinct from the IRF-1, IRF-2 and the alpha F1 binding proteins and presenting a different affinity pattern from that of the TG protein, is proposed as a candidate for IFN-type I gene regulation.