Biofabrication of anin-vitrobone model for Gaucher disease.

Gaucher disease (GD), the most prevalent lysosomal disorder, is caused byGBA1gene mutations, leading to deficiency of glucocerebrosidase, and accumulation of glycosphingolipids in cells of the mononuclear phagocyte system. While skeletal diseases are the leading cause of morbidity and reduced quality of life in GD, the pathophysiology of bone involvement is not yet fully understood, partly due to lack of relevant human model systems. In this work, we present the first 3D human model of GD using aspiration-assisted freeform bioprinting, which enables a platform tool with a potential for decoding the cellular basis of the developmental bone abnormalities in GD. In this regard, human bone marrow-derived mesenchymal stem cells (obtained commercially) and peripheral blood mononuclear cells derived from a cohort of GD patients, at different severities, were co-cultured to form spheroids and differentiated into osteoblast and osteoclast lineages, respectively. Co-differentiated spheroids were then 3D bioprinted into rectangular tissue patches as a bone tissue model for GD. The results revealed positive alkaline phosphatase (ALP) and tartrate-resistant ALP activities, with multi-nucleated cells demonstrating the efficacy of the model, corroborating with gene expression studies. There were no significant changes in differentiation to osteogenic cells but pronounced morphological deformities in spheroid formation, more evident in the 'severe' cohort, were observed. Overall, the presented GD model has the potential to be adapted to personalized medicine not only for understanding the GD pathophysiology but also for personalized drug screening and development.

Selective screening for lysosomal storage disorders in a large cohort of minorities of African descent shows high prevalence rates and novel variants.

Population studies point to regional and ethnicity-specific differences in genetic predisposition for some lysosomal storage disorders (LSDs). The aim of the study was to determine the prevalence of the three treatable forms of lysosomal storage disorders (Gaucher disease [GD], Pompe disease [PD], and Fabry disease [FD]) in a cohort of mostly urban-dwelling individuals of African ancestry, a previously unknown genetic landscape for LSDs. Large-scale selective multistep biochemical and genetic screening was performed in patients seeking healthcare for various health concerns. Fluorimetric enzyme assays for GD, PD, and FD were performed on dried blood spots. Targeted gene sequencing was performed on samples that showed significantly lower enzyme activities (<10% of control mean) after two tiers of enzymatic screening. A total of 5287 unique samples representing a cross section of patients who visited Howard University Hospital and College of Medicine from 2015 to 2017 were included in the study. Study samples were obtained from a population where ~90% reported as African-American, ~5% Hispanic, and <5% Caucasian or other. Regarding GD, three subjects had either homozygous or heterozygous mutations in the GBA gene. As to PD, eight subjects were either homozygous or compound heterozygous for GAA mutations, including three novel mutations: (a) c.472 A > G; p.T158A, (b) c.503G > T; p.R168L, (c) c.1985del. Regarding FD, two subjects had pathogenic GLA mutations, and four had single nucleotide polymorphisms in the 5'UTR, previously implicated in modulating gene expression. The findings highlight a higher incidence of abnormal enzyme levels and pathogenic mutations in the target population reflecting ancestry-based specific genotype and phenotype variations.

Enzyme replacement therapy reverses B lymphocyte and dendritic cell dysregulations in patients with Gaucher Disease.

Gaucher disease (GD) is caused by mutations in the GBA gene encoding lysosomal enzyme, ß-glucocerebrosidase (GCase). GCase deficiency results in accumulation of its substrates in cells of macrophage lineage, affecting multiple organ systems. Enzyme replacement therapy (ERT) with recombinant human GCase is the standard of care to treat GD. In GD, it is well established that there are immune alterations, clinically presenting as lymphadenopathy, gammopathies, and predisposition to hematological cancers. We examined the effect of ERT on immune dysregulations in treatment-naïve GD patients longitudinally after the initiation of ERT. Immunophenotyping was performed in peripheral blood samples obtained before and after ERT. T and B lymphocyte subsets, NK, NKT and dendritic cells were evaluated. In all treatment naïve patients at baseline, transitional B cells, characterized by CD21low expression were markedly elevated. After establishment of stable-dose therapy, CD21low cells were significantly reduced and subsequent increase in CD21Hi B lymphocytes indicated improved B cell maturation. Class-switching and memory B cell defects which were noted prior to treatment were found to be normalized. An increase in dendritic cells also resulted after the treatment. Our data shows that GD affects across various immune cell types and ERT or its effects directly improve affected immunological parameters.

Gaucheromas: When macrophages promote tumor formation and dissemination.

Deficiency of the lysosomal enzyme, ß-glucocerebrosidase, and accumulation of its substrate in cells of the reticuloendothelial system affects multiple organ systems in patients with Gaucher disease (GD). Lipid laden macrophages turn into Gaucher cells (GC) which are the pathological characteristic of GD. GC focally accumulate in the liver, spleen and at extraosseous sites to form benign lesions called Gaucheromas. Gaucheromas pose diagnostic and therapeutic challenges. We studied the pathophysiology of extraosseous Gaucheroma formation in a cohort of patients with GD. Among 63 patients followed at a single center, 3 patients with genotypes L444P/L444P and N370S/N370S, were diagnosed with extraosseous Gaucheromas. Flow cytometry revealed a higher expression of CD16+/CCR4+ non-classical monocytes in blood of GD patients who have developed Gaucheromas. A biopsy showed infiltration of GC, which reactivity against CD163, CD68 and VEGF. The cell proliferative marker Ki67 and CCL2, a factor anti-tumor activity, were negative. Our study indicates that extraosseous Gaucheromas are comprised of cellular elements with characteristics of tumor-associated macrophages, the major players in cancer related inflammation. The occurrence of non-classical CD16+/CCR4+ monocytes reflect the underlying cause for the accumulation of the macrophages capable of migrating to distant sites outside the reticuloendotheial system, and giving rise to tumor-like Gaucheromas.

Time of Initiating Enzyme Replacement Therapy Affects Immune Abnormalities and Disease Severity in Patients with Gaucher Disease.

Gaucher disease (GD) patients often present with abnormalities in immune response that may be the result of alterations in cellular and/or humoral immunity. However, how the treatment and clinical features of patients impact the perturbation of their immunological status remains unclear. To address this, we assessed the immune profile of 26 GD patients who were part of an enzyme replacement therapy (ERT) study. Patients were evaluated clinically for onset of GD symptoms, duration of therapy and validated outcome measures for ERT. According to DS3 disease severity scoring system criteria, they were assigned to have mild, moderate or severe GD. Flow cytometry based immunophenotyping was performed to analyze subsets of T, B, NK, NKT and dendritic cells. GD patients showed multiple types of immune abnormalities associated to T and B lymphocytes with respect to their subpopulations as well as memory and activation markers. Skewing of CD4 and CD8 T cell numbers resulting in lower CD4/CD8 ratio and an increase in overall T cell activation were observed. A decrease in the overall B cells and an increase in NK and NKT cells were noted in the GD patients compared to controls. These immune alterations do not correlate with GD clinical type or level of biomarkers. However, subjects with persistent immune alterations, especially in B cells and DCs correlate with longer delay in initiation of ERT (ΔTX). Thus, while ERT may reverse some of these immune abnormalities, the immune cell alterations become persistent if therapy is further delayed. These findings have important implications in understanding the immune disruptions before and after treatment of GD patients.

Persistent immune alterations and comorbidities in splenectomized patients with Gaucher disease.

Gaucher disease (GD) is an autosomal recessive disorder caused by mutations in the gene encoding acid-ß-glucosidase, resulting in functional disruptions in degradation of glycosphingolipids and lysosomal accumulation of the substrates. The most frequent clinical presentations of GD are thrombocytopenia, splenomegaly and bone pain. Prior to advent of enzyme replacement therapy, splenectomy was performed for complications of hypersplenism such as severe thrombocytopenia and transfusion dependency. Though there is evidence about worsening bone disease after splenectomy, there is no systematic study to assess its effects on the immune system in GD patients. In order to investigate the long-term immunological effects of splenectomy, we used flow cytometry to compare the immunophenotypes of GD patients who had undergone splenectomy (SGD) to those with intact spleen. The results show that SGD patients have significantly fewer CD27(+)/IgM(+) B-cells but more CD4(+)/CD45RO(+) and CD8(+)/CD45RO(+) T-cells. The most surprising finding was an almost complete absence of circulating dendritic cells in SGD patients. In addition, splenectomized subjects had comorbidities, the most common being monoclonal gammopathy of undetermined significance (MGUS). Taken together, these results highlight the persistence of multiple immune alterations and comorbidities coexisting in higher frequency in the SGD group and they are not affected by GD specific therapy.

Efficient procurement of epithelial stem cells from human tissue specimens using a Rho-associated protein kinase inhibitor Y-27632.

The efficient culture of stem cells from epithelial tissues such as skin and corneas is important for both experimental studies and clinical applications of tissue engineering. We now demonstrate that treatment of human-skin-derived keratinocytes with a Rho-associated protein kinase inhibitor Y-27632 for the initial 6 days of primary culture can increase the number of keratinocytes that possess stem cell properties to form colonies during in vitro culture of freshly isolated cells and subsequent passage (50-fold). Further, we show that Y-27632 treatment can increase the total number of prostate epithelial cells derived from human prostate specimens. Therefore, the use of Y-27632 during primary cultures offers a simple and effective way to prepare a large number of epithelial stem cells from various human epithelial tissues.