Augmented glycolytic activity in circulating T cells of systemic sclerosis

Systemic Sclerosis (SSc) is a rare fibrotic autoimmune disorder for which no curative treatments currently exist. Metabolic remodelling has recently been implicated in other autoimmune diseases; however, its potential role in SSc has received little attention. Here, we aimed to determine whether changes to glycolysis and glutaminolysis are important features of skin fibrosis. TGF‐β1, the quintessential pro‐fibrotic stimulus, was used to activate fibrotic pathways in NHDFs in vitro. Dermal fibroblasts derived from lesions of SSc patients were also used for in vitro experiments. Parameters of glycolytic function were assessed using by measuring extracellular acidification in response to glycolytic activators/inhibitors, whilst markers of fibrosis were measured by Western blotting following the use of the glycolysis inhibitors 2‐dg and 3PO and the glutaminolysis inhibitor G968. Succinate was also measured after TGF‐β1 stimulation. Itaconate was added to SSc fibroblasts and collagen examined. TGF‐β1 up‐regulates glycolysis in dermal fibroblasts, and inhibition of glycolysis attenuates its pro‐fibrotic effects. Furthermore, inhibition of glutamine metabolism also reverses TGF‐β1‐induced fibrosis, whilst glutaminase expression is up‐regulated in dermal fibroblasts derived from SSc patient skin lesions, suggesting that enhanced glutamine metabolism is another aspect of the pro‐fibrotic metabolic phenotype in skin fibrosis. TGF‐β1 was also able to enhance succinate production, with increased succinate shown to be associated with increased collagen expression. Incubation of SSc cells with itaconate, an important metabolite, reduced collagen expression. TGF‐β1 activation of glycolysis is a key feature of the fibrotic phenotype induced by TGF‐B1 in skin cells, whilst increased glutaminolysis is also evident in SSc fibroblasts.

Chronic insulin deficiency, in both man and experimental animal models, has been associated with skeletal alterations, the genesis of which remains unknown. Since cartilage growth and maturation are dependent on the maintenance of adequate glycolytic activity, we evaluated cartilaginous carbohydrate metabolism and epiphyseal growth plate morphology in control, long-term (7 weeks) streptozotocin-induced diabetic and insulintreated diabetic rats. Since parathyroid hormone levels have been shown to be decreased in chronically diabetic rats, we also studied the effect of a low calcium diet (0.1%) on cartilage metabolism and morphology in the insulinopenic state. In vitro incubation of epiphyseal cartilage slices in Kreb's Ringer buffer was performed in 5 mM glucose, with either14C-6-glucose as a glycolytic marker or14C-1-glucose as a pentose phosphate pathway marker. While14C-6-glucose uptake was only marginally reduced in diabetic rat cartilage, lactate production was markedly decreased, approximating 42% of control values, and the activity of the pentose phosphate shunt increased (P<0.01). These biochemical alterations were attended by a marked reduction (P<0.005) in the width of epiphyseal growth plates obtained from rats with untreated diabetes. Both insulin replacement (P<0.001) and dietary calcium restriction (P<0.02) in diabetic animals resulted in a significant increment in the width of epiphyseal growth plates. These morphologic changes were accompanied by a significant (P<0.02) increase in cartilaginous lactate production, in the absence of altered glucose uptake. While insulin treatment corrected glycolysis, it had little effect on the augmented pentose shunt activity, implying stimulation of both these metabolic pathways. Dietary calcium restriction normalized glycolysis and corrected the accelerated activity of the pentose phosphate pathway. We conclude that chronic insulin deficiency in the growing rat is attended by alterations in cartilaginous carbohydrate metabolism which may relate not only to insulinopenia per se, but also to the relative hypoparathyroidism that characterizes the chronic experimental diabetic state. The accumulated data also suggest that these metabolic derangements may account, at least in part, for the reduced longitudinal bone growth observed in this growing animal model.

Thermal ablation is a crucial therapeutic modality for hepatocellular carcinoma (HCC), but its efficacy is often hindered by the high recurrence rate attributed to insufficient ablation. Furthermore, the residual tumors following insufficient ablation exhibit a more pronounced immunosuppressive state, which accelerates the disease progression and leads to immune checkpoint blockade (ICB) resistance. Herein, evidence is presented that heightened intratumoral lactate accumulation, stemming from the augmented glycolytic activity of postablative residual HCC cells, may serve as a crucial driving force in exacerbating the immunosuppressive state of the tumor microenvironment (TME). To address this, an injectable nanoparticles-hydrogel composite system (LOX-MnO2 @Gel) is designed that gradually releases lactate oxidase (LOX)-loaded hollow mesoporous MnO2 nanoparticles at the tumor site to continuously deplete intratumoral lactate via a cascade catalytic reaction. Using subcutaneous and orthotopic HCC tumor-bearing mouse models, it is confirmed that LOX-MnO2 @Gel-mediated local lactate depletion can transform the immunosuppressive postablative TME into an immunocompetent one and synergizes with ICB therapy to significantly inhibit residual HCC growth and lung metastasis, thereby prolonging the survival of mice postablation. The work proposes an appealing strategy for synergistically combining antitumor metabolic therapy with immunotherapy to combat postablative HCC recurrence.

B Lymphocyte Signaling Established by the CD19/CD22 Loop Regulates Autoimmunity in the Tight-Skin Mouse

Altered intracellular enzyme activity of monocytes and lymphocytes in Hodgkin's disease