A Phosphomimetic Mutation Stabilizes SOD1 and Rescues Cell Viability in the Context of an ALS-Associated Mutation

The majority of amyotrophic lateral sclerosis (ALS)-related mutations in the enzyme Cu,Zn superoxide dismutase (SOD1), as well as a post-translational modification, glutathionylation, destabilize the protein and lead to a misfolded oligomer that is toxic to motor neurons. The biophysical role of another physiological SOD1 modification, T2-phosphorylation, has remained a mystery. Here, we find that a phosphomimetic mutation, T2D, thermodynamically stabilizes SOD1 even in the context of a strongly SOD1-destabilizing mutation, A4V, one of the most prevalent and aggressive ALS-associated mutations in North America. This stabilization protects against formation of toxic SOD oligomers and positively impacts motor neuron survival in cellular assays. We solve the crystal structure of T2D-SOD1 and explain its stabilization effect using discrete molecular dynamics (DMD) simulations. These findings imply that T2-phosphorylation may be a plausible innate cellular protection response against SOD1-induced cytotoxicity, and stabilizing the SOD1 native conformation might offer us viable pharmaceutical strategies against currently incurable ALS

Nonnative SOD1 trimer is toxic to motor neurons in a model of amyotrophic lateral sclerosis

Protein aggregation is a hallmark of neurodegenerative disease and is hypothesized to cause neuron death. Despite extensive study of disease-associated aggregating proteins, mechanisms of neuron death remain a mystery, and no cures or effective treatments yet exist. Here, we demonstrate the toxicity of a small aggregate of the Cu,Zn superoxide dismutase (SOD1) protein, associated with amyotrophic lateral sclerosis (ALS). We present an experimentally verified structural model of this toxic species and show that SOD1 mutants designed to promote formation of this aggregate increase cell death, providing a direct link between aggregate presence and neuron death. Knowledge of toxic species and the ability to manipulate their formation provides a valuable direction for pursuit of therapeutic strategies in ALS

CIP, a Cardiac Isl1-Interacting Protein, Represses Cardiomyocyte Hypertrophy

Mammalian heart has minimal regenerative capacity. In response to mechanical or pathological stress, the heart undergoes cardiac remodeling. Pressure and volume overload in the heart cause increased size (hypertrophic growth) of cardiomyocytes. Whereas the regulatory pathways that activate cardiac hypertrophy have been well established, the molecular events that inhibit or repress cardiac hypertrophy are less known

Differentiation Trajectory of Limbal Stem and Progenitor Cells under Normal Homeostasis and upon Corneal Wounding

Limbal stem cells (LSCs) reside discretely at limbus surrounded by niche cells and progenitor cells. The aim of this study is to identify the heterogeneous cell populations at limbus under normal homeostasis and upon wounding using single-cell RNA sequencing in a mouse model. Two putative LSC types were identified which showed a differentiation trajectory into limbal progenitor cell (LPC) types under normal homeostasis and during wound healing. They were designated as “putative active LSCs” and “putative quiescent LSCs”, respectively, because the former type actively divided upon wounding while the later type stayed at a quiescent status upon wounding. The “putative quiescent LSCs” might contribute to a barrier function due to their characteristic markers regulating vascular and epithelial barrier and growth. Different types of LPCs at different proliferative statuses were identified in unwounded and wounded corneas with distinctive markers. Four maturation markers (Aldh3, Slurp1, Tkt, and Krt12) were screened out for corneal epithelium, which showed an increased expression along the differentiation trajectory during corneal epithelial maturation. In conclusion, our study identified two different types of putative LSCs and several types of putative LPCs under normal homeostasis and upon wounding, which will facilitate the understanding of corneal epithelial regeneration and wound healing

Immunological and short-term brain volume changes in relapsing forms of multiple sclerosis treated with interferon beta-1a subcutaneously three times weekly: an open-label two-arm trial

Abstract Background Brain volume atrophy is observed in relapsing–remitting multiple sclerosis (RRMS). Methods Brain volume changes were evaluated in 23 patients with RRMS treated with interferon β-1a 44 μg given subcutaneously (SC) three times a week (tiw) and 15 healthy controls. Percentages of whole brain and tissue-specific volume change were measured from baseline (0 months) to 3 months, from 3 to 6 months, and from baseline to 6 months using SIENAX Multi Time Point (SX-MTP) algorithms. Immunological status of patients was also determined and correlations between subsets of T cells and changes in brain volume were assessed. Results Interferon β-1a 44 μg SC tiw in 23 patients with RRMS resulted in significant reductions in whole brain and gray matter tissue volume early in the treatment course (baseline to 3 months; mean change; –0.95 %; P = 0.030, –1.52 %; P = 0.004, respectively), suggesting a short-term treatment-induced pseudoatrophy effect. From baseline to 6 months, there were significant correlations observed between decreased T- cell expression of IL-17 F and decreased whole brain and brain tissue-specific volume. Conclusions These findings are consistent with the interpretation of the pseudoatrophy effect as resolution of inflammation following treatment initiation with interferon β-1a 44 μg SC tiw, rather than disease-related tissue loss. Trial registration ClinicalTrials.gov; NCT0108531

The histone methyltransferase Set7/9 promotes myoblast differentiation and myofibril assembly

Set7 associates with the MyoD transcription factor to enhance expression of genes required for muscle differentiation

microRNA-1 and microRNA-206 regulate skeletal muscle satellite cell proliferation and differentiation by repressing Pax7

Pax7 is a target of two miRNAs that are induced during muscle satellite cell differentiation and repressed in response to muscle injury

Potential cooperations between odorant-binding proteins of the scarab beetle Holotrichia oblita Faldermann (Coleoptera: Scarabaeidae).

It was previously thought that the odorant binding proteins (OBPs) in the sensillum lymph might serve as carriers, which could carry lipophilic odorant molecules to olfactory receptors. In this study, two novel OBP genes of the scarab beetle Holotrichia oblita were screened using an antennal cDNA library. The full cDNA of HoblOBP3 and HoblOBP4 was cloned using reverse transcription PCR and rapid amplification of the cDNA ends. Homology modeling of both OBPs was performed using SWISS-MODEL on-line tools. Next, the two OBPs were expressed in Escherichia coli and purified using Ni ion affinity chromatography. The ligand-binding properties of HoblOBP3 and HoblOBP4 in 42 ligands respectively were measured using the fluorescence probe N-phenyl-naphthylamine (1-NPN). The results obtained from competitive binding assays demonstrated that HoblOBP4 showed a broader range of binding affinities to the test compounds, while HoblOBP3 displays more specific binding affinity. Furthermore, other OBPs and CSPs were expressed in Escherichia coli and purified using Ni ion affinity chromatography. Binding curves were measured for binary mixtures of OBPs and CSPs using 1-NPN, and the Scatchard plots exhibited "J"-like nonlinear correlation trends in some samples. In addition, competitive binding assays of the HoblOBP1 and HoblOBP2 mixtures and of the HoblOBP2 and HoblOBP4 mixtures with representative compounds unexpectedly demonstrated good affinity, which revealed extreme differences that were only obtained using the individual proteins. In the immunocytochemical analysis, colocalization of HoblOBP1 and HoblOBP2, and of HoblOBP2 and HoblOBP4, was detected in the sensilla basiconica and sensilla placodea, respectively. All of these results suggested that HoblOBP1 and HoblOBP2, as well as HoblOBP2 and HoblOBP4, may serve as heterodimers in the sensillum lymph

Competitive binding curves of representative ligands to recombinant HoblOBP3 and HoblOBP4.

<p>The chemical structures of the ligands are shown below. A mixture of the protein and 1-NPN with both concentration of 2 µM in Tris-buffer was titrated with 1 mM solution of each competing ligand to final concentrations of 4–24 µM.</p