The Dynamic Interface Between the Bone Marrow Vascular Niche and Hematopoietic Stem Cells in Myeloid Malignancy

Hematopoietic stem cells interact with bone marrow niches, including highly specialized blood vessels. Recent studies have revealed the phenotypic and functional heterogeneity of bone marrow endothelial cells. This has facilitated the analysis of the vascular microenvironment in steady state and malignant hematopoiesis. In this review, we provide an overview of the bone marrow microenvironment, focusing on refined analyses of the marrow vascular compartment performed in mouse studies. We also discuss the emerging role of the vascular niche in “inflamm-aging” and clonal hematopoiesis, and how the endothelial microenvironment influences, supports and interacts with hematopoietic cells in acute myeloid leukemia and myelodysplastic syndromes, as exemplar states of malignant myelopoiesis. Finally, we provide an overview of strategies for modulating these bidirectional interactions to therapeutic effect in myeloid malignancies.DW and KB are supported by the Oglesby Charitable Trust. DW is additionally supported by a Blood Cancer United Kingdom Clinician Scientist Fellowship (number 15030). LM is supported by a grant from the National Blood Foundation (NBF). JS is supported by a Manchester Cancer Research Centre Studentship. ES is supported by research funding from The Christie Charitable Trust and The Academy of Medical Sciences. DD is funded by NBF, the European Hematology Association (EHA), and Fundação Amélia de Mello

Regulation of steroid hormone receptor function by the 52-kDa FK506-binding protein (FKBP52)

The large FK506-binding protein FKBP52 has been characterized as an important positive regulator of androgen, glucocorticoid and progesterone receptor signaling pathways. FKBP52 associates with receptor-Hsp90 complexes and is proposed to have roles in both receptor hormone binding and receptor subcellular localization. Data from biochemical and cellular studies have been corroborated in whole animal models as fkbp52-deficient male and female mice display characteristics of androgen, glucocorticoid and/or progesterone insensitivity. FKBP52 receptor specificity and the specific phenotypes displayed by the fkbp52-deficient mice have firmly established FKBP52 as a promising target for the treatment of a variety of hormone-dependent diseases. Recent studies demonstrated that the FKBP52 FK1 domain and the proline-rich loop within this domain are functionally important for FKBP52 regulation of receptor function. Based on these data, efforts are currently underway to target the FKBP52 FK1 domain and the proline-rich loop with small molecule inhibitors.Fil: Sivils, Jeffrey C. University Of Texas At El Paso; Estados UnidosFil: Storer, Cheryl L.. University Of Texas At El Paso; Estados UnidosFil: Galigniana, Mario Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Cox, Marc B.. University Of Texas At El Paso; Estados Unido

FKBP51 and FKBP52 in signaling and disease

FKBP51 and FKBP52 are diverse regulators of steroid hormone receptor signaling, including receptor maturation, hormone binding and nuclear translocation. Although structurally similar, they are functionally divergent, which is largely attributed to differences in the FK1 domain and the proline-rich loop. FKBP51 and FKBP52 have emerged as likely contributors to a variety of hormone-dependent diseases, including stress-related diseases, immune function, reproductive functions and a variety of cancers. In addition, recent studies have implicated FKBP51 and FKBP52 in Alzheimer's disease and other protein aggregation disorders. This review summarizes our current understanding of FKBP51 and FKBP52 interactions within the receptor-chaperone complex, their contributions to health and disease, and their potential as therapeutic targets for the treatment of these diseases.Fil: Storer, Cheryl L.. University Of Texas At El Paso; Estados UnidosFil: Dickey, Chad A.. University of South Florida. Alzheimer’s Institute; Estados UnidosFil: Galigniana, Mario Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Rein, Theo. Max Planck Institute of Psychiatry; AlemaniaFil: Cox, Marc B.. University Of Texas At El Paso; Estados Unido

Secretion of functional papain precursor from insect cells. Requirement for N-glycosylation of the pro-region.

The synthetic gene coding for the precursor of the cysteine protease papain (EC 3.4.22.2) has been expressed using the baculovirus/insect cell system. The prepropapain gene was cloned into the transfer vector IpDC125 behind the polyhedrin promoter. The recombinant construct was then incorporated by homologous recombination into the Autographa californiaca nuclear polyhedrosis virus genome. The host Spodoptera frugiperda Sf9 cells infected with the recombinant baculovirus secrete an enzymatically inactive N-glycosylated papain precursor. This zymogen could be activated in vitro to yield about 400 nmol of active papain per liter of culture. The recombinant active mature papain was enzymatically indistinguishable from natural papain but the precursor was not processed to the same amino acid residue. The insect cells also accumulated prepropapain and glycosylated propapain intracellularly. This accumulation was an indication that there are rate-limiting steps in the secretion of proteins from insect cells in this expression system. Characterization of mutants of the precursor has shown that entry into the secretory pathway and addition of carbohydrate are prerequisite conditions for the production and secretion of functional propapain

Processing of the papain precursor. Purification of the zymogen and characterization of its mechanism of processing.

The precursor of the cysteine protease papain has been expressed and secreted as propapain from insect cells infected with a recombinant baculovirus expressing a synthetic gene coding for prepropapain. This 39-kDa secreted propapain zymogen molecule is glycosylated and can be processed in vitro into an enzymatically active authentic papain molecule of 24.5 kDa (Vernet, T., Tessier, D.C., Richardson, C., Laliberte, F., Khouri, H. E., Bell, A. W., Storer, A. C., and Thomas, D. Y. (1990) J. Biol. Chem. 265, 16661-16666). Recombinant propapain was stabilized with Hg2+ and purified to homogeneity using affinity chromatography, gel filtration, and ion-exchange chromatographic procedures. The maximum rate of processing in vitro was achieved at approximately pH 4.0, at a temperature of 65 degrees C and under reducing conditions. Precursor processing is inhibited by a variety of reversible and irreversible cysteine protease inhibitors but not by specific inhibitors of serine, metallo or acid proteases. Replacement by site-directed mutagenesis of the active site cysteine with a serine at position 25 also prevents processing. The inhibitor 125I-N-(2S,3S)-3-trans-hydroxycarbonyloxiran-2-carbonyl-L-tyrosine benzyl ester covalently labeled the wild type papain precursor, but not the C25S mutant, indicating that the active site is accessible to the inhibitor and is in a native conformation within the precursor. Based on biochemical and kinetic analyses of the activation and processing of propapain we have shown that the papain precursor is capable of autoproteolytic cleavage (intramolecular). Once free papain is released processing can then occur in trans (intermolecular)

Overlap subtype of chronic graft-versus-host disease is associated with an adverse prognosis, functional impairment, and inferior patient-reported outcomes: A Chronic Graft-versus-Host Disease Consortium study

Background The National Institutes of Health Consensus Conference proposed the term “overlap” graft-versus-host disease to describe the situation when both acute and chronic graft-versus-host disease are present. Design and Methods We examined whether the overlap subtype of graft-versus-host disease was associated with a different prognosis, functional limitations, or patient-reported outcomes compared to “classic” chronic graft-versus-host disease without any acute features. Results Prospective data were collected from 427 patients from nine centers. Patients were classified as having overlap (n=352) or classic chronic (n=75) graft-versus-host disease based on reported organ involvement. Overlap cases had a significantly shorter median time from transplantation to cohort enrollment (P=0.01), were more likely to be incident cases (P\u3c0.001), and had a lower platelet count at onset of the graft-versus-host disease (P\u3c0.001). Patients with overlap graft-versus-host disease had significantly greater functional impairment measured by a 2-minute walk test, higher symptom burden and lower Human Activity Profile scores. Quality of life was similar, except patients with overlap graft-versus-host disease had worse social functioning, assessed by the Short Form-36. Multivariable analysis utilizing time-varying covariates demonstrated that the overlap subtype of graft-versus-host disease was associated with worse overall survival (HR 2.1, 95% CI 1.1–4.7; P=0.03) and higher non-relapse mortality (HR 2.8, 95% CI 1.2–8.3; P=0.02) than classic chronic graft-versus-host disease. Conclusions These findings suggest that the presence of acute features in patients with chronic graft-versus-host disease is a marker of adverse prognosis, greater functional impairment, and higher symptom burden

Design, Synthesis, and Evaluation of Tetrasubstituted Pyridines as Potent 5-HT2C Receptor Agonists.

A series of pyrido[3,4-d]azepines that are potent and selective 5-HT2C receptor agonists is disclosed. Compound 7 (PF-04781340) is identified as a suitable lead owing to good 5-HT2C potency, selectivity over 5-HT2B agonism, and in vitro ADME properties commensurate with an orally available and CNS penetrant profile. The synthesis of a novel bicyclic tetrasubstituted pyridine core template is outlined, including rationale to account for the unexpected formation of aminopyridine 13 resulting from an ammonia cascade cyclization.We would like to thank the EPSRC (SVL, grant nº EP/K0099494/1 and nº EP/K039520/1) for financial support.This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/ml500507v

Perceptions of COVID-19 Vaccines: Lessons from Selected Populations Who Experience Discrimination in the Australian Healthcare System

COVID-19 vaccination is particularly challenging among populations who have experienced discrimination in healthcare settings. This paper presents qualitative findings from in-depth interviews about COVID-19 vaccination conducted in Australia between October 2020 and November 2021. Data from four different studies are presented; each population has unique experiences of discrimination within the healthcare system: Aboriginal people; people who inject drugs (PWID); people living with HIV (PLHIV); and gay and bisexual men (GBM). Analyses were guided by the behavioural and social determinants model that forms the basis of the World Health Organization’s “data for action: achieving high uptake of COVID-19 vaccines” interim guidance. All populations viewed vaccination as necessary for community protection, although narratives of community care were most common among Aboriginal people. Concerns about vaccine safety were expressed by all participant groups, although participants living with HIV and GBM were more trusting of vaccines possibly because of their ongoing and usually positive past experiences with biomedical technologies for HIV management and sexual health. Aboriginal participants reported distrust of mainstream government and participants who inject drugs expressed a more generalised suspicion about COVID-19 and its origins. Practical problems related to transport, booking appointments for vaccination and so forth, were more common among participants living with HIV and GBM, possibly because these specific interviews were conducted throughout 2021 when vaccines were more available, whereas data for the other populations were collected before the vaccine rollout. Findings show that vaccine willingness is shaped by past experiences of discrimination in healthcare setting, but different histories of discrimination can differently impact vaccine willingness. Promotional messaging and delivery must take account of these important differences so to not treat these populations homogenously