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ATP-binding cassette (ABC) transporters are ubiquitous molecular pumps that transport a broad range of substrates across biological membranes. Although the structure and function of ABC transporters has been studied extensively, our understanding of their energetics and dynamics remains limited. Here, we present studies of the peptidase-containing ABC transporter 1 (PCAT1), a polypeptide processing and secretion ABC transporter that functions via the classic alternating access mechanism. PCAT1 is a homodimer containing two peptidase (PEP) domains, two transmembrane domains, and two nucleotide-binding domains (NBDs). Using cryoelectron microscopy, we analyzed the structures of wild-type PCAT1 under conditions that either prevent or permit ATP hydrolysis and observed two completely different conformational distributions. In the presence of ATP but absence of Mg2+, PCAT1 adopts an NBD-dimerized, outward-facing conformation. The two PEP domains are dissociated from the transporter core, preventing uncoupled substrate cleavage. The addition of Mg2+ to promote ATP hydrolysis shifts the majority of the particles into NBDseparated, inward-facing conformations. Under this ATP turnover condition, only a small fraction of PCAT1 adopts the NBDdimerized conformation. These data give rise to two mechanistic conclusions: 1) the ATP-bound, NBD-dimerized conformation is the lowest energy state, and 2) the rate-limiting step in the PCAT1 transport cycle is the formation of the NBD dimer. The thermodynamic conclusion is likely a general property shared by many ABC transporters. The kinetic bottleneck, however, varies from transporter to transporter.

Rationale: The dynorphin/kappa-opioid receptor (KOR) system (encoded by PDYN and OPRK1 genes respectively) is highly regulated by repeated exposure to drugs of abuse, including mu-opioid agonists and cocaine. These changes in the dynorphin/KOR system can then influence the rewarding effects of these drugs of abuse. Activation of the dynorphin/KOR system is also thought to have a role in the pro-addictive effects of stress. Recent in vitro assays showed that the OPRK1 intron 2 may function as a genomic enhancer in the regulation KOR expression, and contains a glucocorticiod-responsive sequence site. We hypothesize that SNPs in intron 2 of OPRK1 are associated with categorical opioid or cocaine dependence diagnoses, as well as with dimensional aspects of drug use (i.e., magnitude of drug exposure). Methods: This study includes 577 subjects >= 18 years old, with African ancestry (AA) from the USA. They were divided into three groups: 152 control subjects, 142 persons with lifetime opioid dependence diagnosis (OD), and 283 subjects with lifetime cocaine dependence diagnosis (CD). Five SNPs (rs16918909, rs7016778, rs997917, rs6473797, rs10111937) that span 10 Kb nucleotides in intron 2 of OPRK1 were used for the association analyses. Genotyping was performed with the Smokescreen (R) array or sequencing of PCR-amplified DNA fragments. Association analyses for OD and CD diagnoses and the OPRK1 intron 2 alleles were carried out with Fisher's exact test. The Kreek-McHugh-Schluger-Kellogg (KMSK) scales were used for dimensional measure of maximum exposure to specific drugs, using Mann-Whitney tests. Results: Two SNPs, rs997917 and rs10111937 showed point-wise significant allelic association (p < 0.05) with CD diagnosis, and rs10111937 showed a point-wise significance in association with OD. None of these single SNP associations with categorical diagnoses were significant after correction for multiple testing (p(corr) > 0.05). However, significant associations of several genotype patterns (diplotypes) were found with cocaine dependence, but none for opioid dependence. The most significant genotype pattern with cocaine dependence diagnosis occurred for rs6473797 and rs10111937 (p(corr) = 0.036, odds ratio = 1.92, FDR < 0.05), and survived correction for multiple testing. Dimensional analyses with KMSK scores show that persons with either rs997917 or rs10111937 variants had greater exposure to cocaine, compared to those with prototype allele (Mann-Whitney tests, point-wise). Conclusions: This study provides additional support of potential importance of regulatory regions of intron 2 of the OPRK1 gene in development of cocaine and opioid dependence diagnoses, in a population with African-American ancestry.

Plaque psoriasis is a common, chronic, systemic, immune-mediated inflammatory disease. The Janus kinase-signal transducer and activator of transcription pathway plays a major role in intracellular cytokine signaling in inflammatory processes involved in psoriasis. Although Janus kinase (JAK) 1-3 inhibitors have demonstrated efficacy in patients with moderate-to-severe psoriasis, safety concerns persist and no JAK inhibitor has received regulatory approval to treat psoriasis. Thus, an opportunity exists for novel oral therapies that are safe and efficacious in psoriasis. Tyrosine kinase 2 (TYK2) is a member of the JAK family of kinases and regulates signaling and functional responses downstream of the interleukin 12, interleukin 23, and type I interferon receptors. Deucravacitinib, which is an oral, selective inhibitor that binds to the regulatory domain of TYK2, and brepocitinib (PF-06700841) and PF-06826647, which are topical and oral TYK2 inhibitors, respectively, that bind to the active (adenosine triphosphate-binding) site in the catalytic domain, are in development for psoriasis. Selective, allosteric inhibition of TYK2 signaling may reduce the potential for toxicities associated with pan-JAK inhibitors. This article reviews Janus kinase-signal transducer and activator of transcription and TYK2 signaling and the efficacy and safety of JAK inhibitors in psoriasis to date, focusing specifically on TYK2 inhibitors.

Human milk is a complex and dynamic biological system that has evolved to optimally nourish and protect human infants. Yet, according to a recent priority -setting review, "our current understanding of human milk composition and its individual components and their functions fails to fully recognize the importance of the chronobiology and systems biology of human milk in the context of milk synthesis, optimal timing and duration of feeding, and period of lactation" (P. Christian et al., Am J Clin Nutr 113:1063-1072, 2021, https://doi.org/10.1093/ajcn/nqab075). We attribute this critical knowledge gap to three major reasons as follows. (i) Studies have typically examined each subsystem of the mother-milk-infant "triad" in isolation and often focus on a single element or component (e.g., maternal lactation physiology or milk microbiome or milk oligosaccharides or infant microbiome or infant gut physiology). This undermines our ability to develop comprehensive representations of the interactions between these elements and study their response to external perturbations. (ii) Multiomics studies are often cross-sectional, presenting a snapshot of milk composition, largely ignoring the temporal variability during lactation. The lack of temporal resolution precludes the characterization and inference of robust interactions between the dynamic subsystems of the triad. (iii) We lack computational methods to represent and decipher the complex ecosystem of the mother-milk-infant triad and its environment. In this review, we advocate for longitudinal multiomics data collection and demonstrate how incorporating knowledge gleaned from microbial community ecology and computational methods developed for microbiome research can serve as an anchor to advance the study of human milk and its many components as a "system within a system."

Objective: To describe the widespread use of compounded bioidentical hormone therapies (cBHT). To define the term clinical utility and present why there is insufficient evidence to support the overall clinical utility of cBHT products. To recommend actions that pharmacists and regulators can take to promote safer cBHT use. Summary: Nationwide, millions of men and women use cBHT products. Use of these products appears to be increasing year-to-year, according to the limited data reported by the 503 A and 503 B pharmacies that formulate and dispense these products. Although use appears to be widespread, the safety, efficacy, and clinical utility of these products remains unproven. This commentary provides examples of what draws consumers to these products, comparative costs, and formulation challenges. Actions to promote the safe use of cBHT and approaches to begin the study of these products are provided. Conclusion: While significant progress was made via the Drug Supply Chain Security Act in 2013 to improve the safety of compounding practice in general, efforts to further improve the safety and transparency of cBHT dispensing and use must continue, at both the local and national level. (C) 2022 American Pharmacists Association (R). Published by Elsevier Inc. All rights reserved.

Over the past two decades, opioid abuse has risen especially among women. In both sexes hippocampal neural circuits involved in associative memory formation and encoding of motivational incentives are critically important in the transition from initial drug use to drug abuse/dependence. Opioid circuits, particularly the mossy fiber pathway, are crucial for associative memory processes important for addiction. Our anatomical studies, especially those utilizing electron microscopic immunocytochemistry, have provided unique insight into sex differences in the distribution of opioid peptides and receptors in specific hippocampal circuits and how these distributions are altered following stress and oxycodone-associative learning processes. Here we review the hippocampal opioid system in rodents with respect to ovarian hormones effects and baseline sex differences then sex differences following acute and chronic stress. Next, we review sex differences in the hippocampal opioid system in unstressed and chronically stressed rats following oxycodone conditioned place preference. We show that opioid peptides and receptors are distributed within hippocampal circuits in females with elevated estrogen states in a manner that would enhance sensitivity to endogenous and exogenous opioids. Moreover, chronic stress primes the opioid system in females in a manner that would promote opioid-associative learning processes. In contrast, chronic stress has limited effects on the opioid system in males and reduces its capacity to support opioid-mediated learning processes. Interestingly, acute stress appears to prime males for opioid associative learning. On a broader scale the findings highlighted in this review have important implications in understanding sex differences in opioid drug use and abuse.