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

Therapeutic drug monitoring of levetiracetam: Method validation using high-performance liquid chromatography-ultraviolet detector technique and usefulness in patient care setting

Objectives: To develop and validate a modified HPLC-UV method for the estimation of serum levetiracetam levels and to assess the usefulness of serum levetiracetam estimation in epileptic patients. Materials and Methods: Modification of a previously existing HPLC-UV method was performed using liquid– liquid phase extraction and processing using reverse phase analytic HPLC-UV detector technique followed by method validation. Serum samples of patients attending our hospital's Therapeutic Drug Monitoring Outpatient Department services were analyzed for levetiracetam levels using the study method. Data of the past 6 years (2015–2020) were descriptively analyzed. Results: The modified HPLC-UV method was validated as per ICH Q2 (R1) 2005 guidelines. Usefulness of levetiracetam estimation was assessed in 1383 patients (635 children, 683 adults, 40 elderly, and 25 pregnant women). Levetiracetam levels were within the therapeutic range (TR) in 520 children, 543 young adults, 35 elderly patients, and nine pregnant women. In 112 of 232 patients with low levetiracetam levels, poor compliance was elicited. Of 641 patients on polytherapy, 446 patients had levetiracetam values within TR, whereas 29 had values above and 166 patients had values less than TR. Sodium valproate, phenytoin sodium, and carbamazepine affected levetiracetam levels when given concomitantly. Levetiracetam dose was adjusted in 61 patients with abnormal levels for better clinical response. Good seizure control was noted in 913 (82.47%) patients whose levels were within TR, whereas 136 (58.62%) patients with low levels reported an increase in seizure frequency. Conclusions: The modified HPLC-UV method is simple, rapid, efficient, and reliable for assaying serum levetiracetam

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\u27s 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

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

Association of Time since Migration from Rural to Urban Slums and Maternal and Child Outcomes: Dhaka (North and South) and Gazipur City Corporations

This study analyzes data from a new Urban Health and Demographic Surveillance (UHDSS) in five slums in Dhaka (North and South) and Gazipur City Corporations to examine the relationship between migration status and maternal and child health service utilization. Migration status was determined by duration in urban slums (<= 9.99 years, 10-19.99 years, 20+ years, and urban-born). Compared to those born in the city, migrants were characterized by significant disadvantages in every maternal, neonatal, and child health (MNCH) indicator under study, including antenatal care, facility-based delivery, doctor-assisted delivery, child immunization, caesarean-section delivery, and use of modern contraceptives. We found that the level of service coverage among migrants gradually converged-but did not fully converge-to that of the urban-born with increasing duration in the city. We observed a strong positive association between wealth and total MNCH coverage, with a more modest association with higher levels of schooling attainment. Women who were engaged in market employment were less likely to receive adequate coverage, suggesting a tradeoff between livelihood attainment and mother-and-child health. After controlling for these socioeconomic and neighborhood variations in coverage, the duration gradient was diminished but still significant. In line with existing studies of healthcare access, this study highlights the persistent and widespread burden of unequal access to maternal and child health care facing migrants to slum areas, even relative to the overall disadvantages experienced in informal settlements