Rapid Antiretroviral Therapy Initiation for Women in an HIV-1 Prevention Clinical Trial Experiencing Primary HIV-1 Infection during Pregnancy or Breastfeeding

During an HIV-1 prevention clinical trial in East Africa, we observed 16 cases of primary HIV-1 infection in women coincident with pregnancy or breastfeeding. Nine of eleven pregnant women initiated rapid combination antiretroviral therapy (ART), despite having CD4 counts exceeding national criteria for ART initiation; breastfeeding women initiated ART or replacement feeding. Rapid ART initiation during primary HIV-1 infection during pregnancy and breastfeeding is feasible in this setting.     

State‐of‐the‐art CRISPR/Cas9 Technology for Genome Editing in Trypanosomatids

CRISPR/Cas9 technology has revolutionized biology. This prokaryotic defense system against foreign DNA has been repurposed for genome editing in a broad range of cell tissues and organisms. Trypanosomatids are flagellated protozoa belonging to the order Kinetoplastida. Some of its most representative members cause important human diseases affecting millions of people worldwide, such as Chagas disease, sleeping sickness and different forms of leishmaniases. Trypanosomatid infections represent an enormous burden for public health and there are no effective treatments for most of the diseases they cause. Since the emergence of the CRISPR/Cas9 technology, the genetic manipulation of these parasites has notably improved. As a consequence, genome editing is now playing a key role in the functional study of proteins, in the characterization of metabolic pathways, in the validation of alternative targets for antiparasitic interventions, and in the study of parasite biology and pathogenesis. In this work we review the different strategies that have been used to adapt the CRISPR/Cas9 system to Trypanosoma cruzi, Trypanosoma brucei, and Leishmania spp., as well as the research progress achieved using these approaches. Thereby, we will present the state‐of‐the‐art molecular tools available for genome editing in trypanosomatids to finally point out the future perspectives in the field.     

Loss of Notch2 and Notch3 in vascular smooth muscle causes patent ductus arteriosus

The overlapping roles of the predominant Notch receptors in vascular smooth muscle cells, Notch2 and Notch3, have not been clearly defined in vivo. In this study, we use a smooth muscle‐specific deletion of Notch2 together with a global Notch3 deletion to produce mice with combinations of mutant and wild‐type Notch2/3 alleles in vascular smooth muscle cells. Mice with complete loss of Notch3 and smooth muscle‐expressed Notch2 display late embryonic lethality and subcutaneous hemorrhage. Mice without smooth muscle‐Notch2 and only one wild‐type copy of Notch3 die within one day of birth and present with vascular defects, most notably patent ductus arteriosus (DA) and aortic dilation. These defects were associated with decreased expression of contractile markers in both the DA and aorta. These results demonstrate that Notch2 and Notch3 have overlapping roles in promoting development of vascular smooth muscle cells, and together contribute to functional closure of the DA. genesis 53:738–748, 2015. © 2015 Wiley Periodicals, Inc.     

Estimating PMTCT's Impact on Heterosexual HIV Transmission: A Mathematical Modeling Analysis

Introduction

Prevention of mother-to-child HIV transmission (PMTCT) strategies include combined short-course antiretrovirals during pregnancy (Option A), triple-drug antiretroviral treament (ART) during pregnancy and breastfeeding (Option B), or lifelong ART (Option B+). The WHO also recommends ART for HIV treatment and prevention of sexual transmission of HIV. The impact of PMTCT strategies on prevention of sexual HIV transmission of HIV is not known. We estimated the population-level impact of PMTCT interventions on heterosexual HIV transmission in southwestern Uganda and KwaZulu-Natal, South Africa, two regions with different HIV prevalence and fertility rates.

Materials and Methods

We constructed and validated dynamic, stochastic, network-based HIV transmission models for each region. PMTCT Options A, B, and B+ were simulated over ten years under three scenarios: 1) current ART and PMTCT coverage, 2) current ART and high PMTCT coverage, and 3) high ART and PMTCT coverage. We compared adult HIV incidence after ten years of each intervention to Option A (and current ART) at current coverage.

Results

At current coverage, Options B and B+ reduced heterosexual HIV incidence by about 5% and 15%, respectively, in both countries. With current ART and high PMTCT coverage, Option B+ reduced HIV incidence by 35% in Uganda and 19% in South Africa, while Option B had smaller, but meaningful, reductions. The greatest reductions in HIV incidence were achieved with high ART and PMTCT coverage. In this scenario, all PMTCT strategies yielded similar results.

Discussion

Implementation of Options B/B+ reduces adult HIV incidence, with greater effect (relative to Option A at current levels) in Uganda than South Africa. These results are likely driven by Uganda’s higher fertility rates.     

Systematic Cell-Based Phenotyping of Missense Alleles Empowers Rare Variant Association Studies: A Case for LDLR and Myocardial Infarction

A fundamental challenge to contemporary genetics is to distinguish rare missense alleles that disrupt protein functions from the majority of alleles neutral on protein activities. High-throughput experimental tools to securely discriminate between disruptive and non-disruptive missense alleles are currently missing. Here we establish a scalable cell-based strategy to profile the biological effects and likely disease relevance of rare missense variants in vitro. We apply this strategy to systematically characterize missense alleles in the low-density lipoprotein receptor (LDLR) gene identified through exome sequencing of 3,235 individuals and exome-chip profiling of 39,186 individuals. Our strategy reliably identifies disruptive missense alleles, and disruptive-allele carriers have higher plasma LDL-cholesterol (LDL-C). Importantly, considering experimental data refined the risk of rare LDLR allele carriers from 4.5- to 25.3-fold for high LDL-C, and from 2.1- to 20-fold for early-onset myocardial infarction. Our study generates proof-of-concept that systematic functional variant profiling may empower rare variant-association studies by orders of magnitude.