No abstract

Differentiation of naive CD4+ T-cells into functionally distinct T helper (Th) subsets is critical to immunity against pathogen infection. Little is known about the role of signals emanating from the nuclear envelope for T-cell differentiation. The nuclear envelope protein lamin A/C is induced in naive CD4+ T-cells upon antigen recognition and acts as a link between the nucleus and the plasma membrane during T-cell activation. Here we demonstrate that the absence of lamin A/C in naive T-cell reduces Th1 differentiation without affecting Th2 differentiation in vitro and in vivo. Moreover, Rag1−/− mice reconstituted with Lmna−/−CD4+CD25− T-cells and infected with vaccinia virus show weaker Th1 responses and viral removal than mice reconstituted with wild-type T-cells. Th1 responses and pathogen clearance upon Leishmania major infection were similarly diminished in mice lacking lamin A/C in the complete immune system or selectively in T-cells. Lamin A/C mediates Th1 polarization by a mechanism involving T-bet and IFNγ production. Our results reveal a novel role for lamin A/C as key regulator of Th1 differentiation in response to viral and intracellular parasite infections.

Hybrid zones and the consequences of hybridization have contributed greatly to our understanding of evolutionary processes. Hybrid zones also provide valuable insight into the dynamics of symbiosis since each subspecies or species brings its unique microbial symbionts, including germline bacteria such as Wolbachia, to the hybrid zone. Here, we investigate a natural hybrid zone of two subspecies of the meadow grasshopper Chorthippus parallelus in the Pyrenees Mountains. We set out to test whether co-infections of B and F Wolbachia in hybrid grasshoppers enabled horizontal transfer of phage WO, similar to the numerous examples of phage WO transfer between A and B Wolbachia co-infections. While we found no evidence for transfer between the divergent co-infections, we discovered horizontal transfer of at least three phage WO haplotypes to the grasshopper genome. Subsequent genome sequencing of uninfected grasshoppers uncovered the first evidence for two discrete Wolbachia supergroups (B and F) contributing at least 448 kb and 144 kb of DNA, respectively, into the host nuclear genome. Fluorescent in situ hybridization verified the presence of Wolbachia DNA in C. parallelus chromosomes and revealed that some inserts are subspecies-specific while others are present in both subspecies. We discuss our findings in light of symbiont dynamics in an animal hybrid zone.

The mechanisms by which lamin A/C in CD4 + T-cells control intestinal homeostasis and can cause inflammatory bowel disease (IBD) are unknown. Here, we explore lamin A/C in a mouse model of IBD. Adoptive transfer to Rag1 −/− mice of Lmna −/− CD4 + T-cells, which have enhanced regulatory T-cells (Treg) differentiation and function, induced less severe IBD than wild-type T-cells. Lamin A/C deficiency in CD4 + T-cells enhanced transcription of the Treg master regulator FOXP3, thus promoting Treg differentiation, and reduced Th1 polarization, due to epigenetic changes in the Th1 master regulator T-bet. In mesenteric lymph nodes, retinoic acid (RA) released by CD103 + dendritic cells downregulated lamin A/C in CD4 + T-cells, enhancing Treg differentiation. However, non-RA-producing CD103 − dendritic cells predominated in peripheral lymph nodes, facilitating lamin A/C expression in CD4 + T-cells and therefore Th1 differentiation. Our findings establish lamin A/C as a key regulator of Th differentiation in physiological conditions and show it as a potential immune-regulatory target in IBD.No conflicts of interest were declared. immune-mediated inflammatory diseases are Th17 and Treg [12,13]. Th17 polarization is induced by IL-23, IL-6, and TGF-β, which promote expression of the master Th17 transcription factor Rorγt. Treg differentiation

Alzheimer's disease (AD) and cardiovascular disease (CVD) are strongly associated. Both are multifactorial disorders with long asymptomatic phases and similar risk factors. Indeed, CVD signatures such as cerebral microbleeds, micro‐infarcts, atherosclerosis, cerebral amyloid angiopathy and a procoagulant state are highly associated with AD. However, AD and CVD co‐development and the molecular mechanisms underlying such associations are not understood. Here, we review the evidence regarding the vascular component of AD and clinical studies using anticoagulants that specifically evaluated the development of AD and other dementias. Most studies reported a markedly decreased incidence of composite dementia in anticoagulated patients with atrial fibrillation, with the highest benefit for direct oral anticoagulants. However, sub‐analyses by differential dementia diagnosis were scarce and inconclusive. We finally discuss whether anticoagulation could be a plausible preventive/therapeutic approach for AD and, if so, which would be the best drug and strategy to maximize clinical benefit and minimize potential risks.