TEB/POLQ plays dual roles in protecting Arabidopsis from NO-induced DNA damage.

Nitric oxide (NO) is a key player in numerous physiological processes. Excessive NO induces DNA damage, but how plants respond to this damage remains unclear. We screened and identified an Arabidopsis NO hypersensitive mutant and found it to be allelic to TEBICHI/POLQ, encoding DNA polymerase θ. The teb mutant plants were preferentially sensitive to NO- and its derivative peroxynitrite-induced DNA damage and subsequent double-strand breaks (DSBs). Inactivation of TEB caused the accumulation of spontaneous DSBs largely attributed to endogenous NO and was synergistic to DSB repair pathway mutations with respect to growth. These effects were manifested in the presence of NO-inducing agents and relieved by NO scavengers. NO induced G2/M cell cycle arrest in the teb mutant, indicative of stalled replication forks. Genetic analyses indicate that Polθ is required for translesion DNA synthesis across NO-induced lesions, but not oxidation-induced lesions. Whole-genome sequencing revealed that Polθ bypasses NO-induced base adducts in an error-free manner and generates mutations characteristic of Polθ-mediated end joining. Our experimental data collectively suggests that Polθ plays dual roles in protecting plants from NO-induced DNA damage. Since Polθ is conserved in higher eukaryotes, mammalian Polθ may also be required for balancing NO physiological signaling and genotoxicity.

[Prevention and treatment of lung cancer by regulating tumor-associated macrophages with traditional Chinese medicine].

Lung cancer is one of the common malignant tumors in the world, and its incidence and mortality is increasing year by year. Interactions between tumor cells and immune cells in the tumor microenvironment(TME) affect tumor proliferation, infiltration, and metastasis. Tumor-associated macrophages(TAMs) are prominent components of TME, and they have dual regulation effects on malignant progression of lung cancer. The number, activity, and function of M2 macrophages are related to the poor prognosis of lung cancer, and M2 macrophages participate in tumor angiogenesis and immune escape. It has been proved that traditional Chinese medicines(TCMs) and their active ingredients can enhance the antitumor effects, reduce the toxicity of chemotherapy and radiotherapy, and prolong the survival rates of patients with cancer. This paper summarized the role of TAMs in the lung cancer initiation and progression, explored the molecular mechanism of TCM in regulating the recruitment, polarization phenotype, activity, and expression of related factors and proteins of TAMs, and discussed related signal pathways in the prevention and treatment of lung cancer based on the TCM theory of "reinforcing healthy qi and eliminating pathogen". This paper is expected to provide new ideas for the immunotherapy of targeted TAMs.

miRNA-206 regulates human pulmonary microvascular endothelial cell apoptosis via targeting in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a leading cause of death due to tis high morbidity and mortality. microRNAs have emerged as new biomarkers for the prognosis and diagnosis of patients with COPD. In this study, we aimed to investigate the expression of microRNA-206 (miR-206) in lung tissues from COPD patients and to explore the regulatory role of miR-206 in the human pulmonary microvascular endothelial cells (HPMECs). Our results showed that cigarette smoke extract (CSE) promoted cell apoptosis, increased caspase-3 activity, and upregulated the expression of miR-206 in HPMECs, which was significantly reversed by the miR-206 knockdown. Transfection with miR-206 mimics led to cell apoptosis and was closely related to changes in the protein expression levels of caspase-3, caspase-9, and Bcl-2 in HPMECs. Further bioinformatics prediction analysis revealed that the 3'-untranslated region (3'UTR) of Notch3 and vascular endothelial growth factor-A (VEGFA) harbored miR-206-binding sites, and overexpression of miR-206 repressed the luciferase activity of the vectors containing Notch3 and VEGFA 3'UTR. Overexpression of either Notch3 or VEGFA attenuated miR-206-induced cell apoptosis in HPMECs. More importantly, miR-206 expression was upregulated in the lung tissues from COPD patients and was positively corrected with forced expiratory volume 1% predicted in COPD patients, while Notch3 and VEGFA mRNA levels were downregulated and were negatively correlated with the expression level of miR-206 in the lung tissues from COPD patients. In conclusion, our results showed that miR-206 was upregulated in COPD patients and CSE-treated HPMECs, promoted cell apoptosis via directly targeting Notch3 and VEGFA in HPMECs.

Tetrahydrofolate Modulates Floral Transition through Epigenetic Silencing.

Folates, termed from tetrahydrofolate (THF) and its derivatives, function as coenzymes in one-carbon transfer reactions and play a central role in synthesis of nucleotides and amino acids. Dysfunction of cellular folate metabolism leads to serious defects in plant development; however, the molecular mechanisms of folate-mediated cellular modifications and physiological responses in plants are still largely unclear. Here, we reported that THF controls flowering time by adjusting DNA methylation-regulated gene expression in Arabidopsis (Arabidopsis thaliana). Wild-type seedlings supplied with THF as well as the high endogenous THF content mutant dihydrofolate synthetase folypoly-Glu synthetase homolog B exhibited significant up-regulation of the flowering repressor of Flowering Wageningen and thereby delaying floral transition in a dose-dependent manner. Genome-wide transcripts and DNA methylation profiling revealed that THF reduces DNA methylation so as to manipulate gene expression activity. Moreover, in accompaniment with elevated cellular ratios between monoglutamylated and polyglutamylated folates under increased THF levels, the content of S-adenosylhomo-Cys, a competitive inhibitor of methyltransferases, was obviously higher, indicating that enhanced THF accumulation may disturb cellular homeostasis of the concerted reactions between folate polyglutamylation and folate-dependent DNA methylation. In addition, we found that the loss-of-function mutant of CG DNA methyltransferase MET1 displayed much less responsiveness to THF-associated flowering time alteration. Taken together, our studies revealed a novel regulatory role of THF on epigenetic silencing, which will shed lights on the understanding of interrelations in folate homeostasis, epigenetic variation, and flowering control in plants.

Nitric oxide negatively regulates AKT1-mediated potassium uptake through modulating vitamin B6 homeostasis in Arabidopsis.

Nitric oxide (NO), an active signaling molecule in plants, is involved in numerous physiological processes and adaptive responses to environmental stresses. Under high-salt conditions, plants accumulate NO quickly, and reorganize Na(+) and K(+) contents. However, the molecular connection between NO and ion homeostasis is largely unknown. Here, we report that NO lowers K(+) channel AKT1-mediated plant K(+) uptake by modulating vitamin B6 biosynthesis. In a screen for Arabidopsis NO-hypersensitive mutants, we isolated sno1 (sensitive to nitric oxide 1), which is allelic to the previously noted mutant sos4 (salt overly sensitive 4) that has impaired Na(+) and K(+) contents and overproduces pyridoxal 5'-phosphate (PLP), an active form of vitamin B6. We showed that NO increased PLP and decreased K(+) levels in plant. NO induced SNO1 gene expression and enzyme activity, indicating that NO-triggered PLP accumulation mainly occurs through SNO1-mediated vitamin B6 salvage biosynthetic pathway. Furthermore, we demonstrated that PLP significantly repressed the activity of K(+) channel AKT1 in the Xenopus oocyte system and Arabidopsis root protoplasts. Together, our results suggest that NO decreases K(+) absorption by promoting the synthesis of vitamin B6 PLP, which further represses the activity of K(+) channel AKT1 in Arabidopsis. These findings reveal a previously unidentified pivotal role of NO in modulating the homeostasis of vitamin B6 and potassium nutrition in plants, and shed light on the mechanism of NO in plant acclimation to environmental changes.

Nitric oxide induces cotyledon senescence involving co-operation of the NES1/MAD1 and EIN2-associated ORE1 signalling pathways in Arabidopsis.

After germination, cotyledons undertake the major role in supplying nutrients to the pre-photoautorophy angiosperm seedlings until they senesce. Like other senescence processes, cotyledon senescence is a programmed degenerative process. Nitric oxide can induce premature cotyledon senescence in Arabidopsis thaliana, yet the underlying mechanism remains elusive. A screen for genetic mutants identified the nes1 mutant, in which cotyledon senescence was accelerated by nitric oxide. Map-based cloning revealed that NES1 is allelic to a previously reported mitotic checkpoint family gene, MAD1. The nes1/mad1 mutants were restored to the wild type, in response to nitric oxide, by transforming them with pNES1::NES1. Ectopic expression of NES1 in the wild type delayed nitric oxide-mediated cotyledon senescence, confirming the repressive role of NES1. Moreover, two positive regulators of leaf senescence, the ethylene signalling component EIN2 and the transcription factor ORE1/AtNAC2/ANAC092, were found to function during nitric oxide-induced senescence in cotyledons. The block of ORE1 function delayed senescence and ectopic expression induced the process, revealing the positive role of ORE1. EIN2 was required to induce ORE1. Furthermore, the genetic interaction analysis between NES1 and ORE1 showed that the ore1 loss-of-function mutants were epistatic to nes1, suggesting the dominant role of ORE1 and the antagonistic role of NES1 during nitric oxide-induced cotyledon senescence in Arabidopsis.

[Role of Ferroptosis in Non-small Cell Lung Cancer and Progress 
of Traditional Chinese Medicine Intervention].

Non-small cell lung cancer (NSCLC) is one of the malignant tumors with high morbidity and mortality worldwide. Ferroptosis is a new type of programmed cell death caused by abnormal accumulation of iron-dependent reactive oxygen species (ROS) leading to lipid peroxidation. It involves the balance between iron metabolism, lipid metabolism, oxygen free radical reaction and lipid peroxidation. Recent studies have found that ferroptosis is closely related to the occurrence and development of NSCLC. Due to the emergence of chemotherapy resistance and radiotherapy resistance in the treatment of NSCLC, there is an urgent need to develop new effective drugs and treatment strategies. Traditional Chinese medicine has unique advantages in the prevention and treatment of NSCLC due to its multi-targets and minimal side effects. In this review, we summarize the mechanism of ferroptosis in NSCLC, and discuss the research status of active ingredients of traditional Chinese medicine, single-herb traditional Chinese medicine and Chinese herbal compounds in the intervention of NSCLC through ferroptosis, in order to provide a new theoretical basis for the research of ferroptosis pathway and the prevention and treatment of NSCLC by targeted ferroptosis of traditional Chinese medicine.
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Cinobufagin inhibits M2­like tumor­associated macrophage polarization to attenuate the invasion and migration of lung cancer cells.

Macrophages have crucial roles in immune responses and tumor progression, exhibiting diverse phenotypes based on environmental cues. In the present study, the impact of cinobufagin (CB) on macrophage polarization and the consequences on tumor­associated behaviors were investigated. Morphological transformations of THP­1 cells into M0, M1 and M2 macrophages were observed, including distinct changes in the size, shape and adherence properties of these cells. CB treatment inhibited the viability of A549 and LLC cells in a concentration­dependent manner, with an IC50 of 28.8 and 30.12 ng/ml, respectively. CB at concentrations of <30 ng/ml had no impact on the viability of M0 macrophages and lung epithelial (BEAS­2B) cells. CB influenced the expression of macrophage surface markers, reducing CD206 positivity in M2 macrophages without affecting CD86 expression in M1 macrophages. CB also altered certain expression profiles at the mRNA level, notably downregulating macrophage receptor with collagenous structure (MARCO) expression in M2 macrophages and upregulating tumor necrosis factor­α and interleukin­1ß in both M0 and M1 macrophages. Furthermore, ELISA analyses revealed that CB increased the levels of pro­inflammatory cytokines in M1 macrophages and reduced the levels of anti­inflammatory factors in M2 macrophages. CB treatment also attenuated the migration and invasion capacities of A549 and LLC cells stimulated by M2 macrophage­conditioned medium. Additionally, CB modulated peroxisome proliferator­activated receptor γ (PPARγ) and MARCO expression in M2 macrophages and epithelial­mesenchymal transition in A549 cells, which was partially reversed by rosiglitazone, a PPARγ agonist. Finally, CB and cisplatin treatments hindered tumor growth in vivo, with distinct impacts on animal body weight and macrophage marker expression in tumor tissues. In conclusion, the results of the present study demonstrated that CB exerted complex regulatory effects on macrophage polarization and tumor progression, suggesting its potential as a modulator of the tumor microenvironment and a therapeutic for cancer treatment.

[Baicalin alleviates LPS-induced acute lung injury in rats by regulating macrophage polarization].

Objective To investigate the effect of baicalin on acute lung injury (ALI) induced by lipopolysaccharide (LPS), and to explore the roles of M1/M2 polarization of pulmonary macrophages and M1/M2 macrophage-mediated inflammation in the effect. Methods Sixty SD rats were divided into six groups: normal control group, LPS group, (10, 50, 100) mg/kg baicalin combined with LPS group, and dexamethasone (DEX) group. ALI models were established by intratracheal instillation of LPS. After 24 hours, bronchoalveolar lavage fluid (BALF) and bilateral lung tissues were collected. The pathological changes of rat lung tissue were observed by HE staining, and the wet/dry mass ratio (W/D) of lung tissue was measured; the contents of IL-1ß, IL-6, TNF-α, and IL-10 in BALF were detected by ELISA; the M1 macrophage marker inducible nitric oxide synthase (iNOS) and the M2 macrophage marker CD206 in CD68 positive macrophages were detected by immunofluorescence cytochemical staining; the mRNA expressions of iNOS, IL-1ß, Arg1, and CD206 were detected by real-time PCR, and the protein expressions of iNOS and Arg1 were detected by Western blot analysis. Results Baicalin significantly reduced lung lesions and lung water content in ALI rats, and down-regulated the secretion levels of pro-inflammatory cytokines TNF-α, IL-6, and IL-1ß, while up-regulated the secretion of anti-inflammatory cytokine IL-10 in BALF. Baicalin significantly inhibited the lung macrophage polarization to M1 phenotype, and promoted the polarization to M2 phenotype. Baicalin significantly decreased the mRNA and protein expression levels of IL-1ß and iNOS, while increased the mRNA and protein expression levels of CD206 and Arg1 in lung tissues. Conclusion Baicalin can inhibit the lung macrophage polarization to M1 phenotype, promote the polarization to M2 phenotype, and reduce the M1/M2 ratio, thereby alleviating the LPS-induced pulmonary inflammatory response in ALI rats.