Evaluating protein cross-linking as a therapeutic strategy to stabilize SOD1 variants in a mouse model of familial ALS.

Mutations in the gene encoding Cu-Zn superoxide dismutase 1 (SOD1) cause a subset of familial amyotrophic lateral sclerosis (fALS) cases. A shared effect of these mutations is that SOD1, which is normally a stable dimer, dissociates into toxic monomers that seed toxic aggregates. Considerable research effort has been devoted to developing compounds that stabilize the dimer of fALS SOD1 variants, but unfortunately, this has not yet resulted in a treatment. We hypothesized that cyclic thiosulfinate cross-linkers, which selectively target a rare, 2 cysteine-containing motif, can stabilize fALS-causing SOD1 variants in vivo. We created a library of chemically diverse cyclic thiosulfinates and determined structure-cross-linking-activity relationships. A pre-lead compound, "S-XL6," was selected based upon its cross-linking rate and drug-like properties. Co-crystallographic structure clearly establishes the binding of S-XL6 at Cys 111 bridging the monomers and stabilizing the SOD1 dimer. Biophysical studies reveal that the degree of stabilization afforded by S-XL6 (up to 24°C) is unprecedented for fALS, and to our knowledge, for any protein target of any kinetic stabilizer. Gene silencing and protein degrading therapeutic approaches require careful dose titration to balance the benefit of diminished fALS SOD1 expression with the toxic loss-of-enzymatic function. We show that S-XL6 does not share this liability because it rescues the activity of fALS SOD1 variants. No pharmacological agent has been proven to bind to SOD1 in vivo. Here, using a fALS mouse model, we demonstrate oral bioavailability; rapid engagement of SOD1G93A by S-XL6 that increases SOD1G93A's in vivo half-life; and that S-XL6 crosses the blood-brain barrier. S-XL6 demonstrated a degree of selectivity by avoiding off-target binding to plasma proteins. Taken together, our results indicate that cyclic thiosulfinate-mediated SOD1 stabilization should receive further attention as a potential therapeutic approach for fALS.

Allogeneic B cell immunomodulatory therapy in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is an orphan neurodegenerative disease. Immune system dysregulation plays an essential role in ALS onset and progression. Our preclinical studies have shown that the administration of exogenous allogeneic B cells improves outcomes in murine models of skin and brain injury through a process termed pligodraxis, in which B cells adopt an immunoregulatory and neuroprotective phenotype in an injured environment. Here, we investigated the effects of B-cell therapy in the SOD1G93A mouse preclinical model of ALS and in a person living with ALS. Purified splenic mature naïve B cells from haploidentical donor mice were administered intravenously in SOD1G93A mice for a total of 10 weekly doses. For the clinical study in a person with advanced ALS, IgA gammopathy of unclear significance, and B lymphopenia, CD19+ B cells were positively selected from a healthy haploidentical donor and infused intravenously twice, at a 60-day interval. Repeated intravenous B-cell administration was safe and significantly delayed disease onset, extended survival, reduced cellular apoptosis, and decreased astrogliosis in SOD1G93A mice. Repeated B-cell infusion in a person with ALS was safe and did not appear to generate a clinically evident inflammatory response. An improvement of 5 points on the ALSFRS-R scale was observed after the first infusion. Levels of inflammatory markers showed persistent reduction post-infusion. This represents a first demonstration of the efficacy of haploidentical B-cell infusion in the SOD1G93A mouse and the safety and feasibility of using purified haploidentical B lymphocytes as a cell-based therapeutic strategy for a person with ALS.

A Hierarchical Model To Understand the Processing of Polysaccharides/Protein-Based Films in Ionic Liquids.

In recent years, biomaterials from abundant and renewable sources have shown potential in medicine and materials science alike. In this study, we combine theoretical modeling, molecular dynamics simulations, and several experimental techniques to understand the regeneration of cellulose/silk-, chitin/silk-, and chitosan/silk-based biocomposites after dissolution in ionic liquid and regeneration in water. We propose a novel theoretical model that correlates the composite's microscopic structure to its bulk properties. We rely on modeling non-cross-linked biopolymers that present layer-like structures such as ß-sheets and we successfully predict structural, thermal, and mechanical properties of a mixture of these biomolecules. Our model and experiments show that the solubility of the pure substance in the chosen solvent can be used to modulate the amount of crystallinity of the biopolymer blend, as measured by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Thermogravimetric analysis (TGA) shows that the decomposition temperature of the blended biocomposites compared to their pure counterparts is reduced in accordance with our theoretical predictions. The morphology of the material is further characterized through scanning electron microscopy (SEM) and shows differently exposed surface area depending on the blend. Finally, differential scanning calorimetry (DSC) is performed to characterize the residual water content in the material, essential for explaining the regeneration process in water. As a final test of the model, we compare our model's prediction of the Young's modulus with existing data in the literature. The model correctly reproduces experimental trends observed in the Young's modulus due to varying the concentration of silk in the biopolymer blend.

Six-minute walk performance and quality of life comparisons in North Carolina cardiac rehabilitation programs.

OBJECTIVE: The purposes of this study were (1). to determine if six-minute walk (6MW) performance improved after short-term cardiac rehabilitation (CR) across multiple outpatient programs; (2). to examine differences in 6MW performance by patient age, sex, and race; and (3). to determine what relationships existed, if any, between 6MW performance and subscales of the Ferrans and Powers' Quality of Life Index-Cardiac Version III (QOLI). DESIGN: Study design was nonexperimental, prospective, and comparative. SETTING: Study setting included 14 outpatient CR programs from urban and rural settings across North Carolina. PATIENTS: Adults aged 40 to 89 years (N = 630; men = 424 [67%], women = 206 [33%]; mean age, 61 +/- 10.32 years) with medically or surgically treated coronary heart disease enrolled in outpatient CR. OUTCOME MEASURES: Study measures included scores on the QOLI and distance walked (feet) on the 6MW test. RESULTS: Six-minute walk tests and QOLI surveys were administered before and immediately after short-term CR participation. Six-minute walk distance increased for all patients in all age categories across programs after CR (P <.0001). As a group, women improved 6MW distance by 15% (1243.9 +/- 301.2 to 1435.3 +/- 298.1; P <.001). Men also improved 6MW distance by 15% (1463.3 +/- 339.5 to 1683.7 +/- 346.9; P <.001) and walked farther than women on both the initial and follow-up 6MW tests (P <.0001). By age, there were no differences in 6MW scores between men and women aged 40 to 49 years (n = 58) and 50 to 59 years (n = 140; P = 0.54). Both of these age groups had greater initial and discharge 6MW scores than those aged 70 to 79 years (n = 183) and 80 to 89 years (n = 22; P <.001). Those aged 60 to 69 years (n = 227) had lower 6MW scores than those aged 40 to 49 years (P = 0.001) and 50 to 59 years (P <.05), and greater scores than those aged 70 to 79 years (P <.05) and 80 to 89 years (P <.05). Those aged 70 to 79 years had greater initial and follow-up 6MW scores than those aged 80 to 89 years(P <.001). Overall improvements in 6MW performance were found in both white subjects (n = 575; P <.001) and African-Americans (n = 54; P <.001). There were no apparent relationships between 6MW performance and overall or Health and Function QOLI scores (r <.21). CONCLUSIONS: Participation in short-term outpatient CR improved 6MW performance in patients aged 40 to 89 years across 14 programs in North Carolina. No relationships were found between 6MW performance and any domain of the QOLI, including the Health and Function domain.

Validity and reliability of the North Carolina 6-minute cycle test.

PURPOSE: The purposes of this investigation were to determine (1) if the 6-minute cycle (6MC) test is a valid and reliable measure of physical performance in cardiac patients and (2) if physiologic responses to the 6-minute walk (6MW) and 6MC tests differ in men and women. METHODS: Subjects were 101 phase II cardiac rehabilitation patients aged 40 to 79 years. Each subject performed a maximal graded exercise test (MGXT), a 6MW test, and three 6MC tests on separate days. RESULTS: Pearson product moment correlation r values ranged from 0.78 to 0.89 (P = .001) when the three 6MC tests were compared with one another, indicating good test/retest reliability. The 6MC tests were all significantly and positively correlated to 6MW distance (P < .01), with r values ranging from 0.55 to 0.59. Each 6MC test was also correlated with maximal graded exercise test total time (P < .01), with r values ranging from 0.51 to 0.63, and with estimated maximal metabolic equivalents (P < .01), with r values ranging from 0.44 to 0.60. Although heart rate, systolic blood pressure, rate-pressure product, and rating of perceived exertion values for men were greater during the 6MC test than during the 6MW test (P < .001), no differences were seen in these parameters between tests in women (P = .166 to.260), with the exception of a greater exercise rating of perceived exertion seen during the 6MC test(P = .009). CONCLUSION: The North Carolina 6MC test seems to provide a valid and reliable measure of functional abilities in phase II cardiac rehabilitation participants. Men generally present with greater heart rate, systolic blood pressure, and rate-pressure product values during this test than do the women when compared with a standard 6MW test.