MAB201P Sigma-AldrichMouse Anti-Rabbit light chain, HRP conjugate Antibody

Molecular diagnostic tools with non-invasive properties that allow detection of pathological events in Alzheimer's disease (AD) and other neurodegenerative tauopathies are essential for the development of therapeutics. Several diagnostic strategies based on the identification of biomarkers have been proposed. However, its specificity among neurodegenerative disorders is disputable as the association with pathological events remains elusive. Recently, we showed that Amphiphysin-1 (AMPH1) protein's abundance is reduced in the central nervous system (CNS) of the tauopathy mouse model JNPL3 and AD brains. AMPH1 is a synaptic protein that plays an important role in clathrin-mediated endocytosis and associates with BIN1, one of the most important risk loci for AD. Also, it has been associated with a rare neurological disease known as Stiff-Person Syndrome (SPS). Auto-antibodies against AMPH1 are used as diagnostic biomarkers for a paraneoplastic variant of SPS. Therefore, we set up to evaluate the presence and abundance of auto-AMPH1 antibodies in tau-mediated neurodegeneration. Immunoblots and enzyme-linked immunosorbent assays (ELISA) were conducted to detect the presence of auto-AMPH1 antibodies in sera from euthanized mice that developed neurodegeneration (JNPL3) and healthy control mice (NTg). Results showed increased levels of auto-AMPH1 antibodies in JNPL3 sera compared to NTg controls. The abundance of auto-AMPH1 antibodies correlated with motor impairment and AMPH1 protein level decrease in the CNS. The results suggest that auto-AMPH1 antibodies could serve as a biomarker for the progression of tau-mediated neurodegeneration in JNPL3 mice.

Signaling by tumor necrosis factor (TNF) receptor 1 (TNF-R1), a prototypic member of the death receptor family, mediates pleiotropic biological outcomes ranging from inflammation and cell proliferation to cell death. Although many elements of specific signaling pathways have been identified, the main question of how these selective cell fate decisions are regulated is still unresolved. Here we identified TNF-induced K63 ubiquitination of TNF-R1 mediated by the ubiquitin ligase RNF8 as an early molecular checkpoint in the regulation of the decision between cell death and survival. Downmodulation of RNF8 prevented the ubiquitination of TNF-R1, blocked the internalization of the receptor, prevented the recruitment of the death-inducing signaling complex and the activation of caspase-8 and caspase-3/7, and reduced apoptotic cell death. Conversely, recruitment of the adaptor proteins TRADD, TRAF2, and RIP1 to TNF-R1, as well as activation of NF-κB, was unimpeded and cell growth and proliferation were significantly enhanced in RNF8-deficient cells. Thus, K63 ubiquitination of TNF-R1 can be sensed as a new level of regulation of TNF-R1 signaling at the earliest stage after ligand binding.

Activation of cells intrinsic to the vessel wall is central to the initiation and progression of vascular inflammation. As the dominant cellular constituent of the vessel wall, vascular smooth muscle cells (VSMCs) and their functions are critical determinants of vascular disease. While factors that regulate VSMC proliferation and migration have been identified, the endogenous regulators of VSMC proinflammatory activation remain incompletely defined. The Kruppel-like family of transcription factors (KLFs) are important regulators of inflammation. In this study, we identified Kruppel-like factor 15 (KLF15) as an essential regulator of VSMC proinflammatory activation. KLF15 levels were markedly reduced in human atherosclerotic tissues. Mice with systemic and smooth muscle-specific deficiency of KLF15 exhibited an aggressive inflammatory vasculopathy in two distinct models of vascular disease: orthotopic carotid artery transplantation and diet-induced atherosclerosis. We demonstrated that KLF15 alters the acetylation status and activity of the proinflammatory factor NF-κB through direct interaction with the histone acetyltransferase p300. These studies identify a previously unrecognized KLF15-dependent pathway that regulates VSMC proinflammatory activation.

A general mechanism for how intracellular signaling pathways in human pluripotent cells are coordinated and how they maintain self-renewal remain to be elucidated. In this report, we describe a signaling mechanism where PI3K/Akt activity maintains self-renewal by restraining prodifferentiation signaling through suppression of the Raf/Mek/Erk and canonical Wnt signaling pathways. When active, PI3K/Akt establishes conditions where Activin A/Smad2,3 performs a pro-self-renewal function by activating target genes, including Nanog. When PI3K/Akt signaling is low, Wnt effectors are activated and function in conjunction with Smad2,3 to promote differentiation. The switch in Smad2,3 activity after inactivation of PI3K/Akt requires the activation of canonical Wnt signaling by Erk, which targets Gsk3β. In sum, we define a signaling framework that converges on Smad2,3 and determines its ability to regulate the balance between alternative cell states. This signaling paradigm has far-reaching implications for cell fate decisions during early embryonic development.

Testosterone supplementation increases muscle mass in older men but has not been shown to consistently improve physical function and activity. It has been hypothesized that physical exercise is required to induce the adaptations necessary for translation of testosterone-induced muscle mass gain into functional improvements. However, the effects of testosterone plus low intensity physical exercise training (T/PT) on functional performance and bioenergetics are unknown. In this pilot study, we tested the hypothesis that combined administration of T/PT would improve functional performance and bioenergetics in male mice late in life more than low-intensity physical training alone. 28-month old male mice were randomized to receive T/PT or vehicle plus physical training (V/PT) for 2 months. Compare to V/PT control, administration of T/PT was associated with improvements in muscle mass, grip strength, spontaneous physical movements, and respiratory activity. These changes were correlated with increased mitochondrial DNA copy number and expression of markers for mitochondrial biogenesis. Mice receiving T/PT also displayed increased expression of key elements for mitochondrial quality control, including markers for mitochondrial fission-and-fusion and mitophagy. Concurrently, mice receiving T/PT also displayed increased expression of markers for reduced tissue oxidative damage and improved muscle quality.Testosterone administered with low-intensity physical training improves grip strength, spontaneous movements, and respiratory activity. These functional improvements were associated with increased muscle mitochondrial biogenesis and improved mitochondrial quality control.

Epstein-Barr virus (EBV), a human γ-herpesvirus, establishes lifelong infection by targeting the adaptive immune system of the host through memory B cells. Although normally benign, EBV contributes to lymphoid malignancies and lymphoproliferative syndromes in immunocompromised individuals. The viral oncoprotein latent membrane protein 1 (LMP-1) is essential for B lymphocyte immortalization by EBV. The constitutive signaling activity of LMP-1 is dependent on homo-oligomerization of its six-spanning hydrophobic transmembrane domain (TMD). However, the mechanism driving LMP-1 intermolecular interaction is poorly understood. Here, we show that the fifth transmembrane helix (TM5) of LMP-1 strongly self-associates, forming a homotrimeric complex mediated by a polar residue embedded in the membrane, D150. Replacement of this aspartic acid residue with alanine disrupts TM5 self-association in detergent micelles and bacterial cell membranes. A full-length LMP-1 variant harboring the D150A substitution is deficient in NFκB activation, supporting the key role of the fifth transmembrane helix in constitutive activation of signaling by this oncoprotein.

Retinal degenerative diseases, such as retinitis pigmentosa and Leber congenital amaurosis, are a leading cause of untreatable blindness with substantive impact on the quality of life of affected individuals and their families. Mouse mutants with retinal dystrophies have provided a valuable resource to discover human disease genes and helped uncover pathways critical for photoreceptor function. Here we show that the rd11 mouse mutant and its allelic strain, B6-JR2845, exhibit rapid photoreceptor dysfunction, followed by degeneration of both rods and cones. Using linkage analysis, we mapped the rd11 locus to mouse chromosome 13. We then identified a one-nucleotide insertion (c.420-421insG) in exon 3 of the Lpcat1 gene. Subsequent screening of this gene in the B6-JR2845 strain revealed a seven-nucleotide deletion (c.14-20delGCCGCGG) in exon 1. Both sequence changes are predicted to result in a frame-shift, leading to premature truncation of the lysophosphatidylcholine acyltransferase-1 (LPCAT1) protein. LPCAT1 (also called AYTL2) is a phospholipid biosynthesis/remodeling enzyme that facilitates the conversion of palmitoyl-lysophosphatidylcholine to dipalmitoylphosphatidylcholine (DPPC). The analysis of retinal lipids from rd11 and B6-JR2845 mice showed substantially reduced DPPC levels compared with C57BL/6J control mice, suggesting a causal link to photoreceptor dysfunction. A follow-up screening of LPCAT1 in retinitis pigmentosa and Leber congenital amaurosis patients did not reveal any obvious disease-causing mutations. Previously, LPCAT1 has been suggested to be critical for the production of lung surfactant phospholipids and biosynthesis of platelet-activating factor in noninflammatory remodeling pathway. Our studies add another dimension to an essential role for LPCAT1 in retinal photoreceptor homeostasis.