Interleukin-37 promotes DMBA/TPA skin cancer through SIGIRR-mediated inhibition of glycolysis in CD103+DC cells.

Interleukin 37 (IL-37), a member of the IL-1 family, is considered a suppressor of innate and adaptive immunity and, hence is a regulator of tumor immunity. However, the specific molecular mechanism and role of IL-37 in skin cancer remain unclear. Here, we report that IL-37b-transgenic mice (IL-37tg) treated with the carcinogenic 7,12-dimethylbenzoanthracene (DMBA)/12-o-tetradecylphorbol-13-acetate (TPA) exhibited enhanced skin cancer and increased tumor burden in the skin by inhibiting the function of CD103+ dendritic cells (DCs). Notably, IL-37 induced rapid phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), and via single immunoglobulin IL-1-related receptor (SIGIRR), inhibited the long-term Akt activation. Specifically, by affecting the SIGIRR-AMPK-Akt signaling axis, which is related to the regulation of glycolysis in CD103+DCs, IL-37 inhibited their anti-tumor function. Our results show that a marked correlation between the CD103+DC signature (IRF8, FMS-like tyrosine kinase 3 ligand, CLEC9A, CLNK, XCR1, BATF3, and ZBTB46) and chemokines C-X-C motif chemokine ligand 9, CXCL10, and CD8A in a mouse model with DMBA/TPA-induced skin cancer. In a word, our results highlight that IL-37 as an inhibitor of tumor immune surveillance through modulating CD103+DCs and establishing an important link between metabolism and immunity as a therapeutic target for skin cancer.

Interleukin-37 promotes colitis-associated carcinogenesis via SIGIRR-mediated cytotoxic T cells dysfunction.

Interleukin-37b (hereafter called IL-37) was identified as fundamental inhibitor of natural and acquired immunity. The molecular mechanism and function of IL-37 in colorectal cancer (CRC) has been elusive. Here, we found that IL-37 transgenic (IL-37tg) mice were highly susceptible to colitis-associated colorectal cancer (CAC) and suffered from dramatically increased tumor burdens in colon. Nevertheless, IL-37 is dispensable for intestinal mutagenesis, and CRC cell proliferation, apoptosis, and migration. Notably, IL-37 dampened protective cytotoxic T cell-mediated immunity in CAC and B16-OVA models. CD8+ T cell dysfunction is defined by reduced retention and activation as well as failure to proliferate and produce cytotoxic cytokines in IL-37tg mice, enabling tumor evasion of immune surveillance. The dysfunction led by IL-37 antagonizes IL-18-induced proliferation and effector function of CD8+ T cells, which was dependent on SIGIRR (single immunoglobulin interleukin-1 receptor-related protein). Finally, we observed that IL-37 levels were significantly increased in CRC patients, and positively correlated with serum CRC biomarker CEA levels, but negatively correlated with the CD8+ T cell infiltration in CRC patients. Our findings highlight the role of IL-37 in harnessing antitumor immunity by inactivation of cytotoxic T cells and establish a new defined inhibitory factor IL-37/SIGIRR in cancer-immunity cycle as therapeutic targets in CRC.

[Mitochondrial respiratory chain complex I deficiency due to 10191T>C mutation in ND3 gene].

This study reviews a case of mitochondrial respiratory chain complex I deficiency due to the 10191T>C mutation in mitochondrial ND3 gene. The previously healthy boy progressively presented with blepharoptosis, weakness, epilepsy and motor regression at age 6 years. Elevated blood lactate and pyruvate were observed. Brain magnetic resonance imaging showed symmetrical lesions in the basal ganglia. Leigh syndrome was thus confirmed. The protein from the mitochondria and genomic DNA of the boy and his parents was collected from peripheral blood leucocytes for the activity test for mitochondrial complex I to V and genetic analysis. The results showed the activity of complex I (33.1 nmol /min in 1 milligram mitochondrial protein) was lower than normal reference value (44.0±5.4 nmol /min in 1 milligram mitochondrial protein). The ratio of complex I to citrate synthase (19.8%) was also lower than normal reference value (48%±11%). The activities of complexes II to V were normal. 10191T>C mutation in ND3 gene of mitochondria was identified in the boy. 10191T>C mutation and complex I deficiency were not detected in his parents. At present, he is 16 years old, and of normal intelligence with spastic paralysis in both lower extremities after treatment. It is concluded that a Chinese boy with isolated complex I deficiency due to 10191T>C mutation in ND3 gene was firstly diagnosed by peripheral leukocytes mitochondrial respiratory chain enzyme assay and gene analysis. This study can provide clinical data for the nosogenesis of Leigh syndrome.

[A case of Leigh syndrome associated with respiratory chain complex I deficiency due to mitochondrial gene 13513G>A mutation].

Leigh syndrome is a genetically heterogeneous disease caused by defects in enzymes involved in aerobic energy metabolism and the Krebs', cycle. Mitonchondrial complex I deficiency is a main cause of Leigh syndrome. In this study, a Chinese child with Leigh syndrome caused by 13513G>A mutation was reported. The proband was the first child of his parents. The previously healthy boy presented with generalized epilepsy at 12 years of age. When he visited Peking University First Hospital at 13 years of age, he had subacute loss of vision in two eyes and temporal defect of visual field in the left eye. He walked with a spastic gait. His blood lactate and pyruvate levels were elevated. Muscle biopsy showed mild lipid accumulation in muscle fiber. An electrocardiogram showed incomplete right bundle branch block. Brain magnetic resonance imaging showed bilateral, symmetrical lesions in the basal ganglia, supporting the diagnosis of Leigh syndrome. 13513G>A mutation was identified by gene analysis in the patient, which led to mitochondrial respiratory chain complex I deficiency. Multivitamins and L-carnitine were administered. At present, the patient is 16 years old and has progressive deterioration with significant muscle weakness and body weight loss. He is absent from school. He has no obvious retardation in intelligence. 13513G>A mutation was first identified by gene analysis in Chinese population with Leigh syndrome. This may be helpful in genetic counseling.