Functional analysis of UDP-glycosyltransferase genes conferring indoxacarb resistance in Spodoptera litura.

UDP-glycosyltransferase (UGT) is the major detoxification enzymes of phase II involved in xenobiotics metabolism, which potentially mediates the formation of insect resistance. Previous transcriptome sequencing studies have found that several UGT genes were upregulated in indoxacarb resistant strains of Spodoptera litura, but whether these UGT genes were involved in indoxacarb resistance and their functions in resistance were unclear. In this study, the UGTs inhibitor, 5-nitrouracil, enhanced the toxicity of indoxacarb against S. litura, preliminarily suggesting that UGTs were participated in indoxacarb resistance. Two UGT genes, UGT33J17 and UGT41D10 were upregulated in the resistant strains and could be induced by indoxacarb. Alignment of UGT protein sequences revealed two conserved donor-binding regions with several key residues that interact with catalytic sites and sugar donors. Further molecular modeling and docking analysis indicated that two UGT proteins were able to stably bind indoxacarb and N-decarbomethoxylated metabolite (DCJW). Furthermore, knockdown of UGT33J17 and UGT41D10 decreased viability of Spli-221 cells and enhanced susceptibility of larvae to indoxacarb. Transgenic overexpression of these genes reduced the toxicity of indoxacarb in Drosophila melanogaster. This work revealed that upregulation of UGT genes significantly contributes to indoxacarb resistance in S. litura, and is of great significance for the development of integrated and sustainable management strategies for resistant pests in the field.

SUPPLEMENTATION WITH NICOTINAMIDE RIBOSIDE ATTENUATES T CELL EXHAUSTION AND IMPROVES SURVIVAL IN SEPSIS.

ABSTRACT: T cell exhaustion is the main cause of sepsis-induced immunosuppression and is associated with the poor prognosis. Nicotinamide adenine dinucleotide (NAD + ) is well known for its anti-aging effect, but its role in sepsis-induced T cell exhaustion remains to be elucidated. In the present study, using a classic septic animal model, we found that the levels of NAD + and its downstream molecule, which is sirtuins 1 (SIRT1), in T cells in sepsis were decreased. Supplementation with nicotinamide ribose (NR), the precursor of NAD + , right after cecal ligation and puncture significantly increased the levels of NAD + and SIRT1. Supplementation with NR alleviated the depletion of mononuclear cells and T lymphocytes in spleen in sepsis and increased the levels of CD3 + CD4 + and CD3 + CD8 + T cells. Interestingly, both Th1 and Th2 cells were expanded after NR treatment, but the balance of Th1/Th2 was partly restored. Nicotinamide ribose also inhibited the regulatory T cells expansion and programmed cell death 1 expression in CD4 + T cells in sepsis. In addition, the bacteria load, organ damage (lung, heart, liver, and kidney), and the mortality of septic mice were reduced after NR supplementation. In summary, these results demonstrate the beneficial effect of NR on sepsis and T cell exhaustion, which is associated with NAD + /SIRT1 pathway.

Oxidative Stress and Antioxidative Therapy in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is clinically characterized by a progressive increase in pulmonary artery pressure, followed by right ventricular hypertrophy and subsequently right heart failure. The underlying mechanism of PAH includes endothelial dysfunction and intimal smooth muscle proliferation. Numerous studies have shown that oxidative stress is critical in the pathophysiology of PAH and involves changes in reactive oxygen species (ROS), reactive nitrogen (RNS), and nitric oxide (NO) signaling pathways. Disrupted ROS and NO signaling pathways cause the proliferation of pulmonary arterial endothelial cells (PAECs) and pulmonary vascular smooth muscle cells (PASMCs), resulting in DNA damage, metabolic abnormalities, and vascular remodeling. Antioxidant treatment has become a main area of research for the treatment of PAH. This review mainly introduces oxidative stress in the pathogenesis of PAH and antioxidative therapies and explains why targeting oxidative stress is a valid strategy for PAH treatment.