Interaction between APOE4 and herpes simplex virus type 1 in Alzheimer's disease

Introduction: Numerous results suggest the implication of infectious agents in the onset of Alzheimer's disease (AD).Methods: In the Bordeaux‐3C prospective cohort, we assessed the impact of herpes simplex virus type 1 (HSV‐1) infection on the incidence of AD according to apolipoprotein E (APOE) status, a genetic susceptibility factor. Cox models were performed to estimate the 10‐year risk of AD associated with anti‐HSV antibodies in 1037 participants according to APOE4 status.Results: Among APOE4 carriers, subjects for whom the frequency of HSV‐1 reactivation is supposed to be high, that is, immunoglobulin M (IgM) positive or elevated levels of IgG, had an increased risk of AD with adjusted hazard ratios (HRs) of 3.68 (1.08–12.55) and 3.28 (1.19–9.03), respectively. No significant association was found in APOE4‐negative subjects.Discussion: These results, in accordance with a solid pathophysiological rationale, suggest a role for HSV‐1 in AD development among subjects with a genetic susceptibility factor, the APOE4 allele

Betacellulin inhibits osteogenic differentiation and stimulates proliferation through HIF-1α

Cellular signaling via epidermal growth factor (EGF) and EGF-like ligands can determine cell fate and behavior. Osteoblasts, which are responsible for forming and mineralizing osteoid, express EGF receptors and alter rates of proliferation and differentiation in response to EGF receptor activation. Transgenic mice over-expressing the EGF-like ligand betacellulin (BTC) exhibit increased cortical bone deposition; however, because the transgene is ubiquitously expressed in these mice, the identity of cells affected by BTC and responsible for increased cortical bone thickness remains unknown. We have therefore examined the influence of BTC upon mesenchymal stem cell (MSC) and pre-osteoblast differentiation and proliferation. BTC decreases the expression of osteogenic markers in both MSCs and pre-osteoblasts; interestingly, increases in proliferation require hypoxia-inducible factor-alpha (HIF-α), as an HIF antagonist prevents BTC-driven proliferation. Both MSCs and pre-osteoblasts express EGF receptors ErbB1, ErbB2, and ErbB3, with no change in expression under osteogenic differentiation. These are the first data that demonstrate an influence of BTC upon MSCs and the first to implicate HIF-α in BTC-mediated proliferation

Epidemiology of atrophic rhinitis in pigs : the role of breeding animals

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