Loss of IGFBP2 mediates alveolar type 2 cell senescence and promotes lung fibrosis.

Accumulation of senescent cells contributes to age-related diseases including idiopathic pulmonary fibrosis (IPF). Insulin-like growth factor binding proteins (IGFBPs) regulate many biological processes; however, the functional contributions of IGFBP2 in lung fibrosis remain largely unclear. Here, we report that intranasal delivery of recombinant IGFBP2 protects aged mice from weight loss and demonstrated antifibrotic effects after bleomycin lung injury. Notably, aged human-Igfbp2 transgenic mice reveal reduced senescence and senescent-associated secretory phenotype factors in alveolar epithelial type 2 (AEC2) cells and they ameliorated bleomycin-induced lung fibrosis. Finally, we demonstrate that IGFBP2 expression is significantly suppressed in AEC2 cells isolated from fibrotic lung regions of patients with IPF and/or pulmonary hypertension compared with patients with hypersensitivity pneumonitis and/or chronic obstructive pulmonary disease. Altogether, our study provides insights into how IGFBP2 regulates AEC2-cell-specific senescence and that restoring IGFBP2 levels in fibrotic lungs can prove effective for patients with IPF.

Role for exosomes with self-antigens and immune regulatory molecules in allo- and auto-immunity leading to chronic immune injury following murine kidney transplantation.

OBJECTIVE: Antibodies against donor human leukocyte antigen are a risk factor for chronic immune injury (CII) following renal transplantation; however, it is often not detectable. The main goal of this study is to gain new insights into the kinetics of exosome release and content in sensitized vs non-sensitized recipients. Towards this, we investigated the role for circulating exosomes with allo and self-antigens as well as immunoregulatory molecules in the development of CII and acute rejection. METHODS: Using murine kidney allograft rejection models, we investigated the role of exosomes on immune responses leading to allo- and auto-immunity to self-antigens resulting in rejection. Exosomes were analyzed for kidney self-antigens (Collagen-IV, fibronectin, angiotensin II receptor type 1), and immune-regulatory molecules (PD-L1, CD73) using western blot. Antibodies to donor MHC in serum samples were detected by immunofluorescence, self-antigens by enzyme-linked immunosorbent assay and kidney tissue infiltrating cells were determined by immunohistochemistry. RESULTS: BALB/c; H2d to C57BL/6; H2b renal transplantation (BALB/c), resulted in tubulitis and cellular infiltration by day 14, suggestive of acute inflammation, that was self-limiting with functioning graft. This contributed to CII on post-transplant day >100, which was preceded by induction of exosomes with donor and self-antigens leading to antibodies and immune-regulatory molecules. The absence of acute rejection in this allogenic transplant model is likely due to the induction of splenic and, graft-infiltrating CD4 + FoxP3+ T regulatory cells. In contrast, prior sensitization by skin graft followed by kidney transplantation induced antibodies to MHC and self-antigens leading to acute rejection. CONCLUSION: We demonstrate a pivotal role for induction of exosomes with immune-regulatory molecules, allo- and auto-immunity to self-antigens leading to chronic immune injury following murine kidney transplantation.

Targeting chromatin dysregulation in organ fibrosis.

Fibrosis leads to destruction of organ architecture accompanied by chronic inflammation and loss of function. Fibrosis affects nearly every organ in the body and accounts for ∼45% of total deaths worldwide. Over the past decade, tremendous progress has been made in understanding the basic mechanisms leading to organ fibrosis. However, we are limited with therapeutic options and there is a significant need to develop highly effective anti-fibrotic therapies. Recent advances in sequencing technologies have advanced the burgeoning field of epigenetics towards molecular understanding at a higher resolution. Here we provide a comprehensive review of the recent advances in chromatin regulatory processes, specifically DNA methylation, post-translational modification of histones, and chromatin remodeling complexes in kidney, liver and lung fibrosis. Although this research field is young, we discuss new strategies for potential therapeutic interventions for treating organ fibrosis.

Live-attenuated H1N1 influenza vaccine candidate displays potent efficacy in mice and ferrets.

Currently, influenza vaccine manufacturers need to produce 1-5 x 107 PFU of each vaccine strain to fill one dose of the current live-attenuated-influenza-vaccine (LAIV). To make a single dose of inactivated vaccine (15 ug of each hemagglutinin), the equivalent of 1010 PFU of each vaccine strains need to be grown. This high dose requirement is a major drawback for manufacturing as well as rapidly sourcing sufficient doses during a pandemic. Using our computer-aided vaccine platform Synthetic Attenuated Virus Engineering (SAVE), we created a vaccine candidate against pandemic H1N1 A/CA/07/2009 (CodaVax-H1N1) with robust efficacy in mice and ferrets, and is protective at a much lower dose than the current LAIV. CodaVax-H1N1 is currently in Phase I/II clinical trials. The hemagglutinin (HA) and neuraminidase (NA) gene segments of A/California/07/2009 (H1N1) (CA07) were "de-optimized" and a LAIV was generated ex silico using DNA synthesis. In DBA/2 mice, vaccination at a very low dose (100 or approximately 1 PFU) with CodaVax-H1N1 prevented disease after lethal challenge with wild-type H1N1. In BALB/c mice, as little as 103 PFU was protective against lethal challenge with mouse-adapted H1N1. In ferrets, CodaVax-H1N1 was more potent compared to currently licensed LAIV and still effective at a low dose of 103 PFU at preventing replication of challenge virus.

Functional decreases in P2X7 receptors are associated with retinoic acid-induced neuronal differentiation of Neuro-2a neuroblastoma cells.

Neuro-2a (N2a) cells are derived from spontaneous neuroblastoma of mouse and capable to differentiate into neuronal-like cells. Recently, P2X7 receptor has been shown to sustain growth of human neuroblastoma cells but its role during neuronal differentiation remains unexamined.We characterized the role of P2X7 receptors in the retinoic acid (RA)-differentiated N2a cells. RA induced N2a cells differentiation into neurite bearing and neuronal specific proteins, microtubule-associated protein 2 (MAP2) and neuronal specific nuclear protein (NeuN), expressing neuronal-like cells. Interestingly, the RA-induced neuronal differentiation was associated with decreases in the expression and function of P2X7 receptors. Functional inhibition of P2X7 receptors by P2X7 receptor selective antagonists, 5'-triphosphate, periodate-oxidized 2',3'-dialdehyde ATP (oATP), brilliant blue G (BBG) or A438079 induced neurite outgrowth. In addition, RA and oATP treatment stimulated the expression of neuron-specific class III beta-tubulin (TuJ1), and knockdown of P2X7 receptor expression by siRNA induced neurite outgrowth. To elucidate the possible mechanism, we found the levels of basal intracellular Ca2+ concentrations ([Ca2+]i) were decreased in either RA- or oATP-differentiated or P2X7receptor knockdown N2a cells. Simply cultured N2a cells in low Ca2+ medium induced a 2-fold increase in neurite length. Treatment of N2a cells with ATP hydrolase apyrase and the P2X7 receptors selective antagonist oATP or BBG decreased cell viability and cell number. Nevertheless, oATP but not BBG decreased cell proliferation and cell cycle progression. These results suggest for the first time that decreases in expression/function of P2X7 receptors are involved in neuronal differentiation.We provide additional evidence shown that the ATP release-activated P2X7 receptor is important in maintaining cell survival of N2a neuroblastoma cells.