Cytokines in Gaucher disease: Role in the pathogenesis of bone and pulmonary disease

Glucocerebrosidase deficiency leads to neuropathology via cellular immune activation

Mutations in GBA (glucosylceramidase beta), which encodes the lysosomal enzyme glucocerebrosidase (GCase), are the strongest genetic risk factor for the neurodegenerative disorders Parkinson's disease (PD) and Lewy body dementia. Recent work has suggested that neuroinflammation may be an important factor in the risk conferred by GBA mutations. We therefore systematically tested the contributions of immune-related genes to neuropathology in a Drosophila model of GCase deficiency. We identified target immune factors via RNA-Seq and proteomics on heads from GCase-deficient flies, which revealed both increased abundance of humoral factors and increased macrophage activation. We then manipulated the identified immune factors and measured their effect on head protein aggregates, a hallmark of neurodegenerative disease. Genetic ablation of humoral (secreted) immune factors did not suppress the development of protein aggregation. By contrast, re-expressing Gba1b in activated macrophages suppressed head protein aggregation in Gba1b mutants and rescued their lifespan and behavioral deficits. Moreover, reducing the GCase substrate glucosylceramide in activated macrophages also ameliorated Gba1b mutant phenotypes. Taken together, our findings show that glucosylceramide accumulation due to GCase deficiency leads to macrophage activation, which in turn promotes the development of neuropathology.

Cathepsin K in Pathological Conditions and New Therapeutic and Diagnostic Perspectives

Cathepsin K (CatK) is a part of the family of cysteine proteases involved in many important processes, including the degradation activity of collagen 1 and elastin in bone resorption. Changes in levels of CatK are associated with various pathological conditions, primarily related to bone and cartilage degradation, such as pycnodysostosis (associated with CatK deficiency), osteoporosis, and osteoarthritis (associated with CatK overexpression). Recently, the increased secretion of CatK is being highly correlated to vascular inflammation, hypersensitivity pneumonitis, Wegener granulomatosis, berylliosis, tuberculosis, as well as with tumor progression. Due to the wide spectrum of diseases in which CatK is involved, the design and validation of active site-specific inhibitors has been a subject of keen interest in pharmaceutical companies in recent decades. In this review, we summarized the molecular background of CatK and its involvement in various diseases, as well as its clinical significance for diagnosis and therapy.

Biological Variation in Peripheral Inflammation and Oxidative Stress Biomarkers in Individuals with Gaucher Disease

The lack of reliable biomarkers is a significant challenge impeding progress in orphan drug development. For appropriate interpretation of intervention-based results or for evaluating candidate biomarkers, other things being equal, lower variability in biomarker measurement would be helpful. However, variability in rare disease biomarkers is often poorly understood. Type 1 Gaucher disease (GD1) is one such rare lysosomal storage disorder. Oxidative stress and inflammation have been linked to the pathophysiology of GD1 and validated measures of these processes can provide predictive value for treatment success or disease progression. This study was undertaken to investigate and compare the extent of longitudinal biological variation over a three-month period for various blood-based oxidative stress and inflammation markers in participants with GD1 on stable standard-of-care therapy (N = 13), treatment-naïve participants with GD1 (N = 5), and in age- and gender-matched healthy volunteers (N = 18). We utilized Bland–Altman plots for visual comparison of the biological variability among the three measurements. We also report group-wise means and the percentage of coefficient of variation (%CV) for 15 biomarkers. Qualitatively, we show specific markers (IL-1Ra, IL-8, and MIP-1b) to be consistently altered in GD1, irrespective of therapy status, highlighting the need for adjunctive therapies that can target and modulate these biomarkers. This information can help guide the selection of candidate biomarkers for future intervention-based studies in GD1 patients.

Abdominal lymphadenopathy in children with Gaucher disease: Relation to disease severity and glucosylsphingosine

Few case reports and series reported abdominal lymphadenopathy (ALN) in people with Gaucher disease (GD). However, it's prevalence among Gaucher population, clinical implications and potential biomarkers are unknown. Hence this study aims to assess the prevalence of ALN among children with GD & to correlate it to neutrophil-lymphocytic-ratio (NLR), platelet-lymphocytic-ratio (PLR) and glucosylsphingosine (Lyso-GL1). Fifty children with GD (14 type-1 and 36 type-3) on enzyme-replacement therapy (ERT) were compared to 50 matched healthy controls, focusing on history of pressure manifestations by ALN (diarrhea, constipation, abdominal pain, intestinal obstruction), and history of splenectomy, with calculation of severity scoring index (SSI). NLR, PLR and Lyso-GL1 were measured. Abdominal-ultrasound was done with assessment of liver and spleen volumes and ALN. CT-scan was done for those having significant lymphadenopathy. Twenty-six children with GD had ALN (52%). The most common presentations were abdominal-pain (22%) & constipation (18%), with intestinal-obstruction in 3 children (6%). Children with GD had significantly higher NLR (p < .001) and decreased PLR (p = .024) compared to controls. Interestingly, children with GD having ALN had significantly higher SSI (.012), Lyso-GL1 (p = .002) and NLR (p = .001) than those without ALN. Multivariate-logistic regression showed that ALN was independently related to Lyso-GL1 (p = .027), NLR (p = .023) and SSI (p = .032). Thus, ALN is a prevalent GD morbidity with wide clinical-spectrum ranging from asymptomatic cases to intestinal obstruction. ALN is related to SSI, NLR and Lyso-GL1 in children with GD.HighlightsChildren with GD had significantly higher NLR and lower PLR compared to controls.Children with GD having ALN had significantly higher SSI, Lyso-GL1 and NLR than those without ALN.ALN was independently related to Lyso-GL1, NLR and SSI in children with GD.

Could insulin receptor H1085H C > T single nucleotide polymorphism predict insulin resistance in type 2 diabetic and chronic hepatitis C virus patients in Egypt?

Background

Insulin-receptor (INSR) is an α2β2 heterotetramer disulfide-linked trans-membrane glycoprotein and a family member of tyrosine kinase receptors. It mediates the pleiotropic actions of insulin regulating glucose homeostasis. It is encoded by a single gene: INSR gene. The INSR gene comprises 22 exons. Exons 17–22 encode the tyrosine kinase domain, and mutations in this region impair the function of the insulin receptor that may cause insulin resistance and hyperinsulinemia. Single nucleotide polymorphism with C > T substitution at His 1058 position of INSR (rs 1799817) located in exon 17 was considered to be involved in insulin resistance. Insulin receptor might be counter-regulated by degradation, differential expression, or modification by phosphorylation in cells expressing HCV core protein. HCV infection eventually leads to liver steatosis and fibrosis, increased oxidative stress, and peroxidation, all of which trigger a cascade of inflammatory responses, thus contributing to the development of insulin resistance. The present retrospective case-control aimed to study INSR H1085H C > T (rs 1799817) SNP in Egyptian patients suffering from chronic HCV infection with DM. The current study was conducted on two hundred and two participants of 100 males and 102 females, divided as follows: the control group (group I) included 50 apparently healthy volunteers of comparable age, sex, and socioeconomic status as patients groups, group II included 50 type 2 DM patients without HCV infection, group III included 52 chronic HCV infected patients without DM, and group IV included 50 HCV patients with DM.

Results

HOMA-IR and QUICKI index was significantly higher in the patient groups (groups II, III, and IV) than in controls (P < 0.001, P = 0.019, and P < 0.001, respectively). It was significantly lower in patients of group III than in patients of groups II and IV with P < 0.001 for both. DM patient group without HCV infection (group II) and HCV with DM (group IV) showed a significant decrease in CC genotypes and a significant increase in TT genotypes than the controls (P < 0.001, P = 0.018, respectively). HCV patients with DM (group IV) had the highest frequency of heterozygous genotype (CT) (50%). HCV-infected patients with T2DM (group IV) also showed a significantly higher frequency of minor allele (T) (35%) than controls (20%), and a lower frequency of the wild allele (C) (65%) than controls (80%).

Conclusion

The mutant allele “T” of INSR H1085H C > T (rs 1799817) SNP might be associated with an increased risk of developing insulin resistance and T2DM.

Consequences of treatment for hemophagocytic lymphohistiocytosis in a patient with undiagnosed Gaucher disease Type 1

Gaucher disease, a lysosomal storage disorder and hemophagocytic lymphohistiocytosis (HLH), a disorder of the immune system, have several overlapping clinical features including cytopenias, elevated serum ferritin, and splenomegaly. Prior reports of acute infantile neuronopathic, Type 2 Gaucher disease manifesting with signs of HLH have been published. Here we describe an adult patient who was initially suspected of having HLH, and was treated with a 10-day course of etoposide and a 5-day course alemtuzumab for presumptive HLH, only to later to have his presentation be determined to be due to Type 1 Gaucher disease. HLH chemotherapy treatment appeared to trigger a severe Gaucher acute pain crisis and extensive bony disease including avascular necrosis. Prolonged immunosuppression, and recurrent infections further complicated a lengthy hospitalization. We discuss the clinical overlap between Gaucher and HLH and the iatrogenic consequences of HLH-directed therapy on underlying Type 1 Gaucher disease.

Gaucher disease-associated alterations in mesenchymal stem cells reduce osteogenesis and favour adipogenesis processes with concomitant increased osteoclastogenesis

Gaucher disease (GD) is caused by pathogenic mutations in GBA1, the gene that encodes the lysosomal enzyme β-glucocerebrosidase. Until now, treatments for GD cannot completely reverse bone problems. The aim of this work was to evaluate the potential of MSCs from GD patients (GD MSCs) to differentiate towards the osteoblast (GD Ob) and adipocyte (GD Ad) lineages, and their role in osteoclastogenesis. We observed that GD Ob exhibited reduced mineralization, collagen deposition and alkaline phosphatase activity (ALP), as well as decreased gene expression of RUNX2, COLA1 and ALP. We also evaluated the process of osteoclastogenesis and observed that conditioned media from GD MSCs supernatants induced an increase in the number of osteoclasts. In this model, osteoclastogenesis was induced by RANKL and IL-1β. Furthermore, results showed that in GD MSCs there was a promotion in NLRP3 and PPAR-γ gene expression. Adipogenic differentiation revealed that GD Ad had an increase in PPAR-γ and a reduced RUNX2 gene expression, promoting adipocyte differentiation. In conclusion, our results show that GD MSCs exhibited deficient GD Ob differentiation and increased adipogenesis. In addition, we show that GD MSCs promoted increased osteoclastogenesis through RANKL and IL-1β. These changes in GD MSCs are likely to contribute to skeletal imbalance observed in GD patients.

Defective Sphingolipids Metabolism and Tumor Associated Macrophages as the Possible Links Between Gaucher Disease and Blood Cancer Development

There is a rising number of evidence indicating the increased risk of cancer development in association with congenital metabolic errors. Although these diseases represent disorders of individual genes, they lead to the disruption of metabolic pathways resulting in metabolite accumulation or their deficiency. Gaucher disease (GD) is an autosomal recessive sphingolipidosis. It is a rare lysosomal storage disease. A strong correlation between GD and different types of cancers, such as multiple myeloma, leukemia, and hepatocellular carcinoma, has been reported. Common features for all types of GD include spleen and liver enlargement, cytopenia, and a variety of bone defects. Overall, the molecular bases leading to the association of GD and cancers are not clearly understood. Here, we describe the role of ceramides in GD, discuss the potential implications of immune cells activation and show how the disturbances in their metabolism might promote blood cancer development.

Neurological effects of glucocerebrosidase gene mutations

The association between Gaucher disease (GD) and Parkinson disease (PD) has been described for almost two decades. In the biallelic state (homozygous or compound heterozygous) mutations in the glucocerebrosidase gene (GBA) may cause GD, in which glucosylceramide, the sphingolipid substrate of the glucocerebrosidase enzyme (GCase), accumulates in visceral organs leading to a number of clinical phenotypes. In the biallelic or heterozygous state, GBA mutations increase the risk for PD. Mutations of the GBA allele are the most significant genetic risk factor for idiopathic PD, found in 5%–20% of idiopathic PD cases depending on ethnicity. The neurological consequences of GBA mutations are reviewed and the proposition that GBA mutations result in a disparate but connected range of clinically and pathologically related neurological features is discussed. The literature relating to the clinical, biochemical and genetic basis of GBA PD, type 1 GD and neuronopathic GD is considered highlighting commonalities and distinctions between them. The evidence for a unifying disease mechanism is considered.

Acid Ceramidase Deficiency is characterized by a unique plasma cytokine and ceramide profile that is altered by therapy

Acid Ceramidase Deficiency (Farber disease, FD) is an ultra-rare Lysosomal Storage Disorder that is poorly understood and often misdiagnosed as Juvenile Idiopathic Arthritis (JIA). Hallmarks of FD are accumulation of ceramides, widespread macrophage infiltration, splenomegaly, and lymphocytosis. The cytokines involved in this abnormal hematopoietic state are unknown. There are dozens of ceramide species and derivatives, but the specific ones that accumulate in FD have not been investigated. We used a multiplex assay to analyze cytokines and mass spectrometry to analyze ceramides in plasma from patients and mice with FD, controls, Farber patients treated by hematopoietic stem cell transplantation (HSCT), JIA patients, and patients with Gaucher disease. KC, MIP-1α, and MCP-1 were sequentially upregulated in plasma from FD mice. MCP-1, IL-10, IL-6, IL-12, and VEGF levels were elevated in plasma from Farber patients but not in control or JIA patients. C16-Ceramide (C16-Cer) and dhC16-Cer were upregulated in plasma from FD mice. a-OH-C18-Cer, dhC12-Cer, dhC24:1-Cer, and C22:1-Cer-1P accumulated in plasma from patients with FD. Most cytokines and only a-OH-C18-Cer returned to baseline levels in HSCT-treated Farber patients. Sphingosines were not altered. Chitotriosidase activity was also relatively low. A unique cytokine and ceramide profile was seen in the plasma of Farber patients that was not observed in plasma from HSCT-treated Farber patients, JIA patients, or Gaucher patients. The cytokine profile can potentially be used to prevent misdiagnosis of Farber as JIA and to monitor the response to treatment. Further understanding of why these signaling molecules and lipids are elevated can lead to better understanding of the etiology and pathophysiology of FD and inform development of future treatments.