Human umbilical cord blood-borne fibroblasts contain marrow niche precursors that form a bone/marrow organoid in vivo

Human umbilical cord blood (CB) has attracted much attention as a reservoir for functional hematopoietic stem and progenitor cells, and, recently, as a source of blood-borne fibroblasts (CB-BFs). Previously, we demonstrated that bone marrow stromal cell (BMSC) and CB-BF pellet cultures make cartilage in vitro. Furthermore, upon in vivo transplantation, BMSC pellets remodelled into miniature bone/marrow organoids. Using this in vivo model, we asked whether CB-BF populations that express characteristics of the hematopoietic stem cell (HSC) niche contain precursors that reform the niche. CB ossicles were regularly observed upon transplantation. Compared with BM ossicles, CB ossicles showed a predominance of red marrow over yellow marrow, as demonstrated by histomorphological analyses and the number of hematopoietic cells isolated within ossicles. Marrow cavities from CB and BM ossicles included donor-derived CD146-expressing osteoprogenitors and host-derived mature hematopoietic cells, clonogenic lineage-committed progenitors and HSCs. Furthermore, human CD34+ cells transplanted into ossicle-bearing mice engrafted and maintained human HSCs in the niche. Our data indicate that CB- BFs are able to recapitulate the conditions by which the bone marrow microenvironment is formed and establish complete HSC niches, which are functionally supportive of hematopoietic tissue

Humoral immune response to SARS-CoV-2 in five different groups of individuals at different environmental and professional risk of infection

It is partially unknown whether the immune response to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection persists with time. To address this issue, we detected the presence of SARS-CoV-2 antibodies in different groups of individuals previously diagnosed with COVID-19 disease (group 1 and 2), or potentially exposed to SARS-CoV-2 infection (group 3 and 4), and in a representative group of individuals with limited environmental exposure to the virus due to lockdown restrictions (group 5). The primary outcome was specific anti-SARS-CoV-2 antibodies in the different groups assessed by qualitative and quantitative analysis at baseline, 3 and 6 months follow-up. The seroconversion rate at baseline test was 95% in group 1, 61% in group 2, 40% in group 3, 17% in group 4 and 3% in group 5. Multivariate logistic regression analysis revealed male gender, close COVID-19 contact and presence of COVID-19 related symptoms strongly associated with serological positivity. The percentage of positive individuals as assessed by the qualitative and quantitative tests was superimposable. At the quantitative test, the median level of SARS-CoV-2 antibody levels measured in positive cases retested at 6-months increased significantly from baseline. The study indicates that assessing antibody response to SARS-CoV-2 through qualitative and quantitative testing is a reliable disease surveillance tool

Performing oncological procedures during COVID-19 outbreak: a picture from an Italian cancer center

Aim: Since SARS-CoV-2 infection rapidly spread around the world, Italy has quickly become one of the most affected countries. Healthcare systems introduced strict infection control measures to ensure optimal care, especially in frail groups such as cancer patients (pts). This study investigated the efficacy of SARS-CoV-2 pre-procedure screening and whether COVID-19 influenced timely diagnosis and therapy. Methods: Data of oncological procedures of pts with confirmed or suspected cancer diagnosis, treated at Oncology Department or coming from Emergency Department of San Luigi Gonzaga Hospital between June 2020 and March 2021 were retrospectively collected. A nasopharyngeal swab (NPS) was performed in outpatients 24/48 h before procedures. Inpatients were tested by NPS before and after hospitalization. Results: Two hundred and twenty-one pts were included in this analysis. Median age was 73 years, males were 58%. Eastern Cooperative Oncology Group (ECOG) Performance Status was 0 or 1 in 88% of pts. The most frequent cancer type was lung cancer (57%). Stages IV were 77%. Two hundred and forty-three scheduled procedures were performed with diagnostic (n: 142; 58%), therapeutic (n: 55; 23%), and palliative (n: 46; 19%) intent. One hundred and four and 139 procedures were performed in out- and in-pts, respectively. Of the 234 NPS performed, 10 (4%) were positive. Two pts were infected during hospitalization, 8 in community. Most of them were asymptomatic, while only 2 had mild symptoms. Eight procedures (3%) were postponed, 1 cancelled, while 2 were performed in positive pts. Median time to resolution of the infection was 17 days (11–36). Median delay in the procedures was 25 days (14–55). Five pts started systemic treatment, after a median time of 37.5 days (13–57). Conclusions: SARS-CoV-2 infection led to the postponement of a small, but not negligible percentage of oncological procedures. However, the low infection rate observed suggests that structured screening for COVID-19 is critical for the best management of scheduled procedures during pandemic

A novel SEMA3G mutation in two siblings affected by syndromic GnRH deficiency

Introduction: Gonadotropin-releasing hormone (GnRH) deficiency causes hypogonadotropic hypogonadism (HH), a rare genetic disorder that impairs sexual reproduction. HH can be due to defective GnRH-secreting neuron development or function and may be associated with other clinical signs in overlapping genetic syndromes. With most of the cases being idiopathic, genetics underlying HH is still largely unknown. Objective: To assess the contribution of mutated Semaphorin 3G (SEMA3G) gene in the onset of a syndromic form of HH, characterized by intellectual disabilities and facial dysmorphic features. Method: By combining homozygosity mapping with exome sequencing, we identified a novel variant in SEMA3G gene. We then applied mouse as a model organism to examine SEMA3G expression and its functional requirement in vivo. Further, we applied homology modelling in silico and cell culture assays in vitro to validate the pathogenicity of the identified gene variant. Results: We found that: SEMA3G is expressed along the migratory route of GnRH neurons and in the developing pituitary; SEMA3G affects GnRH neuron development, but is redundant in the adult hypothalamic-pituitary-gonadal axis; mutated SEMA3G alters binding properties in silico and in vitro to its PlexinAs receptors and attenuates its effect on the migration of immortalized GnRH neurons. Conclusion: In silico, in vitro and in vivo models revealed that SEMA3G regulates GnRH neuron migration and that its mutation affecting receptor selectivity may be responsible for the HH-related defects

Visceral adipose tissue immune homeostasis is regulated by the crosstalk between adipocytes and dendritic cell subsets

Visceral adipose tissue (VAT) has multiple roles in orchestrating whole-body energy homeostasis. In addition, VAT is now considered an immune site harboring an array of innate and adaptive immune cells with a direct role in immune surveillance and host defense. We report that conventional dendritic cells (cDCs) in VAT acquire a tolerogenic phenotype through upregulation of pathways involved in adipocyte differentiation. While activation of the Wnt/β-catenin pathway in cDC1 DCs induces IL-10 production, upregulation of the PPARγ pathway in cDC2 DCs directly suppresses their activation. Combined, they promote an anti-inflammatory milieu in vivo delaying the onset of obesity-induced chronic inflammation and insulin resistance. Under long-term over-nutrition, changes in adipocyte biology curtail β-catenin and PPARγ activation, contributing to VAT inflammation

Rings and Bricks: Expression of Cohesin Components is Dynamic during Development and Adult Life.

Cohesin complex components exert fundamental roles in animal cells, both canonical in cell cycle and non-canonical in gene expression regulation. Germline mutations in genes coding for cohesins result in developmental disorders named cohesinopaties, of which Cornelia de Lange syndrome (CdLS) is the best-known entity. However, a basic description of mammalian expression pattern of cohesins in a physiologic condition is still needed. Hence, we report a detailed analysis of expression in murine and human tissues of cohesin genes defective in CdLS. Using both quantitative and qualitative methods in fetal and adult tissues, cohesin genes were found to be ubiquitously and differentially expressed in human tissues. In particular, abundant expression was observed in hematopoietic and central nervous system organs. Findings of the present study indicate tissues which should be particularly sensitive to mutations, germline and/or somatic, in cohesin genes. Hence, this expression analysis in physiological conditions may represent a first core reference for cohesinopathies.This work has been supported by Fondazione Cariplo, grant No. 2015-0783 to Valentina Massa, and by Fondazione Mariani (Como, Italy) to Angelo Selicorni

BRCA1-associated protein 1 (BAP1) immunohistochemical expression as a diagnostic tool in malignant pleural mesothelioma classification: a large retrospective study

Malignant pleural mesothelioma (MPM) is a highly aggressive disease with limited therapeutic options. Histological subtype remains among the most reliable prognostic factors, because the epithelioid subtype associated with the best prognosis and the sarcomatoid subtype with the worst. The biphasic subtype has an intermediate prognosis, but its definitive histological diagnosis may be challenging owing to the difficulty of assessing the neoplastic nature of the stromal component. Recent data identified BRCA1-associated protein 1 gene (BAP1) as one of the most frequently mutated genes in MPM. Immunohistochemical testing for BRCA1-associated protein 1 (BAP1) has been proposed to be predictive for the detection of BAP1 mutation in neoplastic cells. The aim of the present study was to define the diagnostic usefulness of immunohistochemical determination of BAP1 in MPM, with clinicopathological correlation

CyclinD1 Down-Regulation and Increased Apoptosis Are Common Features of Cohesinopathies

Genetic variants within components of the cohesin complex (NIPBL, SMC1A, SMC3, RAD21, PDS5, ESCO2, HDAC8) are believed to be responsible for a spectrum of human syndromes known as "cohesinopathies" that includes Cornelia de Lange Syndrome (CdLS). CdLS is a multiple malformation syndrome affecting almost any organ and causing severe developmental delay. Cohesinopathies seem to be caused by dysregulation of specific developmental pathways downstream of mutations in cohesin components. However, it is still unclear how mutations in different components of the cohesin complex affect the output of gene regulation. In this study, zebrafish embryos and SMC1A-mutated patient-derived fibroblasts were used to analyze abnormalities induced by SMC1A loss of function. We show that the knockdown of smc1a in zebrafish impairs neural development, increases apoptosis, and specifically down-regulates Ccnd1 levels. The same down-regulation of cohesin targets is observed in SMC1A-mutated patient fibroblasts. Previously, we have demonstrated that haploinsufficiency of NIPBL produces similar effects in zebrafish and in patients fibroblasts indicating a possible common feature for neurological defects and mental retardation in cohesinopathies. Interestingly, expression analysis of Smc1a and Nipbl in developing mouse embryos reveals a specific pattern in the hindbrain, suggesting a role for cohesins in neural development in vertebrates

Transcription factor 7-like 1 is involved in hypothalamo-pituitary axis development in mice and humans

Aberrant embryonic development of the hypothalamus and/or pituitary gland in humans results in congenital hypopituitarism (CH). Transcription factor 7-like 1 (TCF7L1), an important regulator of the WNT/β-catenin signaling pathway, is expressed in the developing forebrain and pituitary gland, but its role during hypothalamo–pituitary (HP) axis formation or involvement in human CH remains elusive. Using a conditional genetic approach in the mouse, we first demonstrate that TCF7L1 is required in the prospective hypothalamus to maintain normal expression of the hypothalamic signals involved in the induction and subsequent expansion of Rathke’s pouch progenitors. Next, we reveal that the function of TCF7L1 during HP axis development depends exclusively on the repressing activity of TCF7L1 and does not require its interaction with β-catenin. Finally, we report the identification of two independent missense variants in human TCF7L1, p.R92P and p.R400Q, in a cohort of patients with forebrain and/or pituitary defects. We demonstrate that these variants exhibit reduced repressing activity in vitro and in vivo relative to wild-type TCF7L1. Together, our data provide support for a conserved molecular function of TCF7L1 as a transcriptional repressor during HP axis development in mammals and identify variants in this transcription factor that are likely to contribute to the etiology of CH