Necroptosis of macrophages is a necessary element in reinforcing intrapulmonary inflammation during acute lung injury (ALI). However, the molecular mechanism that sparks macrophage necroptosis is ...still unclear. Triggering receptor expressed on myeloid cells-1 (TREM-1) is a pattern recognition receptor expressed broadly on monocytes/macrophages. The influence of TREM-1 on the destiny of macrophages in ALI requires further investigation.
TREM-1 decoy receptor LR12 was used to evaluate whether the TREM-1 activation induced necroptosis of macrophages in lipopolysaccharide (LPS)-induced ALI in mice. Then we used an agonist anti-TREM-1 Ab (Mab1187) to activate TREM-1 in vitro. Macrophages were treated with GSK872 (a RIPK3 inhibitor), Mdivi-1 (a DRP1 inhibitor), or Rapamycin (an mTOR inhibitor) to investigate whether TREM-1 could induce necroptosis in macrophages, and the mechanism of this process.
We first observed that the blockade of TREM-1 attenuated alveolar macrophage (AlvMs) necroptosis in mice with LPS-induced ALI. In vitro, TREM-1 activation induced necroptosis of macrophages. mTOR has been previously linked to macrophage polarization and migration. We discovered that mTOR had a previously unrecognized function in modulating TREM-1-mediated mitochondrial fission, mitophagy, and necroptosis. Moreover, TREM-1 activation promoted DRP1
phosphorylation through mTOR signaling, which in turn caused surplus mitochondrial fission-mediated necroptosis of macrophages, consequently exacerbating ALI.
In this study, we reported that TREM-1 acted as a necroptotic stimulus of AlvMs, fueling inflammation and aggravating ALI. We also provided compelling evidence suggesting that mTOR-dependent mitochondrial fission is the underpinning of TREM-1-triggered necroptosis and inflammation. Therefore, regulation of necroptosis by targeting TREM-1 may provide a new therapeutic target for ALI in the future.
Photoperiod/temperature‐sensitive genic male sterility (P/TGMS) is widely applied for improving crop production. Previous investigations using the reversible male sterile (rvms) mutant showed that ...slow development is a general mechanism for restoring fertility to P/TGMS lines in Arabidopsis. In this work, we isolated a restorer of rvms–2 (res3), as the male sterility of rvms–2 was rescued by res3. Phenotype analysis and molecular cloning show that a point mutation in UPEX1 l in res3 leads to delayed secretion of callase A6 from the tapetum to the locule and tetrad callose wall degradation. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis demonstrated that the tapetal transcription factor ABORTED MICROSPORES directly regulates UPEX1 expression, revealing a pathway for tapetum secretory function. Early degradation of the callose wall in the transgenic line eliminated the fertility restoration effect of res3. The fertility of multiple known P/TGMS lines with pollen wall defects was also restored by res3. We propose that the remnant callose wall may broadly compensate for the pollen wall defects of P/TGMS lines by providing protection for pollen formation. A cellular mechanism is proposed to explain how slow development restores the fertility of P/TGMS lines in Arabidopsis.
During pollen development, a temporary callose wall is essential for normal pollen wall formation and male fertility; delayed degradation of this callose wall facilitates the restoration of fertility in photoperiod/temperaturesensitive genic male sterile Arabidopsis.
SUMMARY
Thermosensitive genic female sterility (TGFS) is a promising property to be utilized for hybrid breeding. Here, we identified a rice TGFS line, tfs2, through an ethyl methyl sulfone (EMS) ...mutagenesis strategy. This line showed sterility under high temperature and became fertile under low temperature. Few seeds were produced when the tfs2 stigma was pollinated, indicating that tfs2 is female sterile. Gene cloning and genetic complementation showed that a point mutation from leucine to phenylalanine in HEI10 (HEI10tfs2), a crossover formation protein, caused the TGFS trait of tfs2. Under high temperature, abnormal univalents were formed, and the chromosomes were unequally segregated during meiosis, similar to the reported meiotic defects in oshei10. Under low temperature, the number of univalents was largely reduced, and the chromosomes segregated equally, suggesting that crossover formation was restored in tfs2. Yeast two‐hybrid assays showed that HEI10 interacted with two putative protein degradation‐related proteins, RPT4 and SRFP1. Through transient expression in tobacco leaves, HEI10 were found to spontaneously aggregate into dot‐like foci in the nucleus under high temperature, but HEI10tfs2 failed to aggregate. In contrast, low temperature promoted HEI10tfs2 aggregation. This result suggests that protein aggregation at the crossover position contributes to the fertility restoration of tfs2 under low temperature. In addition, RPT4 and SRFP1 also aggregated into dot‐like foci, and these aggregations depend on the presence of HEI10. These findings reveal a novel mechanism of fertility restoration and facilitate further understanding of HEI10 in meiotic crossover formation.
Significance Statement
Our study promotes the understanding of HEI10/TFS2 for meiotic crossover formation and provides a mechanism for the female fertility restoration of TGFS lines under low temperature.
Natural enemies such as parasitoids and parasites depend on sensitive olfactory to search for their specific hosts. Herbivore-induced plant volatiles (HIPVs) are vital components in providing host ...information for many natural enemies of herbivores. However, the olfactory-related proteins involved in the recognition of HIPVs are rarely reported. In this study, we established an exhaustive tissue and developmental expression profile of odorant-binding proteins (OBPs) from
, an essential natural enemy in the forestry ecosystem. Twenty DhelOBPs displayed various expression patterns in different organs and adult physiological states, suggesting a potential involvement in olfactory perception. In silico AlphaFold2-based modeling and molecular docking showed similar binding energies between six DhelOBPs (DhelOBP4, 5, 6, 14, 18, and 20) and HIPVs from
. While in vitro fluorescence competitive binding assays showed only recombinant DhelOBP4, the most highly expressed in the antennae of emerging adults could bind to HIPVs with high binding affinities. RNAi-mediated behavioral assays indicated that DhelOBP4 was an essential functional protein for
adults recognizing two behaviorally attractive substances:
-cymene and γ-terpinene. Further binding conformation analyses revealed that Phe 54, Val 56, and Phe 71 might be the key binding sites for DhelOBP4 interacting with HIPVs. In conclusion, our results provide an essential molecular basis for the olfactory perception of
and reliable evidence for recognizing the HIPVs of natural enemies from insect OBPs' perspective.
Summary
Glycoside hydrolase 12 (GH12) proteins act as virulence factors and pathogen‐associated molecular patterns (PAMPs) in oomycetes. However, the pathogenic mechanisms of fungal GH12 proteins ...have not been characterized. In this study, we demonstrated that two of the six GH12 proteins produced by the fungus Verticillium dahliae Vd991, VdEG1 and VdEG3 acted as PAMPs to trigger cell death and PAMP‐triggered immunity (PTI) independent of their enzymatic activity in Nicotiana benthamiana. A 63‐amino‐acid peptide of VdEG3 was sufficient for cell death‐inducing activity, but this was not the case for the corresponding peptide of VdEG1. Further study indicated that VdEG1 and VdEG3 trigger PTI in different ways: BAK1 is required for VdEG1‐ and VdEG3‐triggered immunity, while SOBIR1 is specifically required for VdEG1‐triggered immunity in N. benthamiana. Unlike oomycetes, which employ RXLR effectors to suppress host immunity, a carbohydrate‐binding module family 1 (CBM1) protein domain suppressed GH12 protein‐induced cell death. Furthermore, during infection of N. benthamiana and cotton, VdEG1 and VdEG3 acted as PAMPs and virulence factors, respectively indicative of host‐dependent molecular functions. These results suggest that VdEG1 and VdEG3 associate differently with BAK1 and SOBIR1 receptor‐like kinases to trigger immunity in N. benthamiana, and together with CBM1‐containing proteins manipulate plant immunity.
Chloroplast biogenesis is a complex process in higher plants. Screening chloroplast biogenesis mutants, and elucidating their molecular mechanisms, will provide insight into the process of ...chloroplast biogenesis. In this paper, we obtained an early chloroplast biogenesis mutant atecb2 that displayed albino cotyledons and was seedling lethal. Microscopy observations revealed that the chloroplast of atecb2 mutants lacked an organized thylakoid membrane. The AtECB2 gene, which is highly expressed in cotyledons and seedlings, encodes a pentatricopeptide repeat protein (PPR) with a C-terminal DYW domain. The AtECB2 protein is localized in the chloroplast, and contains a conserved HxExnCxxC motif that is similar to the activated site of cytidine deaminase. The AtECB2 mutation affects the expression pattern of plastid-encoded genes. Immunoblot analyses showed that the levels of photosynthetic proteins decreased substantially in atecb2 mutants. Inspection of all reported plastid RNA editing sites revealed that one editing site, accD, is not edited in atecb2 mutants. Therefore, the AtECB2 protein must regulate the RNA editing of this site, and the dysfunctional AccD protein from the unedited RNA molecules could lead to the mutated phenotype. All of these results indicate that AtECB2 is required for chloroplast transcript accD RNA editing and early chloroplast biogenesis in Arabidopsis thaliana.
Berberine (BBR) is an effective cholesterol-lowering drug. Although gut microbiota has been implicated in the pharmacological activities of BBR, little evidence exists on the specific species of gut ...microbiota involved in its therapeutic effects, nor on linking gut bacteria to its recognized hypercholesterolemia-alleviating mechanism–upregulation of the low-density lipoprotein receptor (LDLR) in the liver. The present study was performed to identify the specific species of gut microbiota involved in the anti-hyperlipdemic effect of BBR, and interpret its mechanism through linking the gut microbiota and LDLR. The BBR-enriched gut bacterial species were identified by whole genome shotgun sequencing. Pure cultured B. producta was orally administered to C57BL/6 mice to evaluate its anti-hyperlipdemic effect. The LDLR-upregulating effect of B. producta was evaluated both in vitro and in vivo. Orally administration of BBR (200 mg/kg) decreased serum and liver lipid levels in HFD-induced hyperlipidemic mice. Microbiome analysis indicated that Blautia was closely associated with BBR’s lipid-modulating activities. Further analysis revealed that BBR selectively promoted the growth of Blautia producta. Orally treatment of HFD mice with live B. producta reduced obesity and alleviated hyperlipidemia. Notably, the B. producta significantly increased LDLR expression in the liver, and its spent culture supernatant upregulated the LDLR level and promoted LDL uptake by HepG2 cells. Simultaneously, B. producta also linked butyrate-producing and bile salt hydrolase (BSH)-inhibiting effect of BBR. The gut microbiota, especially B. producta, may confers the hypercholesterolemia-alleviating effects of berberine. B. producta represents a novel probiotic that may be used for the treatment of dyslipidemia.
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Prenatal opioid exposure might disturb epigenetic programming in the brain of neonatal offspring with various consequences for gene expressions and behaviors. This study determined whether altered ...trimethylation of histone 3 at lysine 4 (H3K4me3) in the promoter of the tumor necrosis factor-α (tnf-α) gene with neural cell apoptosis was involved in the ventral-medial striatum, an important brain region for withdrawal symptoms, of neonatal rat offspring from morphine-addicted mothers. Female adult rats were injected with morphine before gestation and until 14 days after giving birth. On postnatal day 14 (P14), rat offspring from morphine-addicted mothers were subjected to an opioid-withdrawal protocol and were analyzed 2 or 8 h after administration of that protocol. Expressions of the TNF-α protein, H3K4me3 in the tnf-α promoter gene, and neural cell apoptosis within the ventral-medial striatum of neonatal rat offspring were evaluated. In the absence of significant opioid withdrawal (2 h after initiation of the opioid-withdrawal protocol on P14), prenatal morphine exposure led to increased levels of H3K4me3 in the tnf-α promoter gene, of the TNF-α protein, and of neural cell apoptosis within the ventral-medial striatum of neonatal rat offspring. Following opioid withdrawal (8 h after initiation of the opioid-withdrawal protocol on P14), differential expression of H3K4me3 in the tnf-α promoter gene locus and upregulation of the level of TNF-α protein expression were further enhanced in these offspring. In addition, increased levels of caspase-3 and neural cell apoptosis were also observed. Taken together, this study revealed that prenatal opioid exposure can activate an epigenetic histone mechanism which regulates proinflammatory factor generation, which hence, led to cell apoptotic damage within the ventral-medial striatum of neonatal rat offspring from morphine-addicted mothers. More importantly, the opioid-withdrawal episode may provide augmented effects for the abovementioned alterations and could lead to deleterious effects in the neonatal brain of such offspring.
Colorectal cancer (CRC) is one of the most common cancers worldwide. Long non-coding RNAs (IncRNAs) have been shown to play important regulatory roles in cancer biology and functional IncRNAs can be ...used for cancer diagnosis and prognosis. One IncRNA that has attracted significant attention is urothelial carcinoma-associated 1 (UCA1), which is significantly up-regulated in most tumour tissues and cancer cells. However, the contributions of UCA1 to CRC remain largely unknown. Thus, the aim of the current study was to investigate the clinical significance and biological function of UCA1 in CRC. First, we evaluated whether UCA1 is detectable or altered in CRC tissues or cell lines compared to adjacent normal tissues or normal cell lines by quantitative real-time polymerase chain reaction. The potential relationship between UCA1 levels in tumour tissues and the clinicopatho-logical features of CRC was then investigated. Finally, we assessed whether UCA1 influences cell proliferation, apoptosis, cell cycle distribution and migration in vitro. Our results demonstrated that UCA1 levels were markedly increased in CRC tissues and cells compared to controls, and this high level of UCA1 expression was significantly correlated with larger tumour size, less differentiated histology and greater tumour depth. In addition, patients with high UCA1 expression had a significantly poorer prognosis than those with low UCA1 expression. Moreover, UCA1 was found to influence the proliferation, apoptosis and cell cycle progression of CRC cells. These data suggest an important role for UCA1 in the molecular aetiology of CRC and suggest a potential application for UCA1 in CRC diagnosis, progression and therapy.
Chimeric antigen receptor (CAR) T cell therapy has demonstrated proven efficacy in some hematologic cancers. We evaluated the safety and efficacy of LCAR-B38M, a dual epitope-binding CAR T cell ...therapy directed against 2 distinct B cell maturation antigen epitopes, in patients with relapsed/refractory (R/R) multiple myeloma (MM).
This ongoing phase 1, single-arm, open-label, multicenter study enrolled patients (18 to 80 years) with R/R MM. Lymphodepletion was performed using cyclophosphamide 300 mg/m
. LCAR-B38M CAR T cells (median CAR+ T cells, 0.5 × 10
cells/kg range, 0.07 to 2.1 × 10
) were infused in 3 separate infusions. The primary objective is to evaluate the safety of LCAR-B38M CAR T cells; the secondary objective is to evaluate the antimyeloma response of the treatment based on the general guidelines of the International Myeloma Working Group.
At data cutoff, 57 patients had received LCAR-B38M CAR T cells. All patients experienced ≥ 1 adverse events (AEs). Grade ≥ 3 AEs were reported in 37/57 patients (65%); most common were leukopenia (17/57; 30%), thrombocytopenia (13/57; 23%), and aspartate aminotransferase increased (12/57; 21%). Cytokine release syndrome occurred in 51/57 patients (90%); 4/57 (7%) had grade ≥ 3 cases. One patient reported neurotoxicity of grade 1 aphasia, agitation, and seizure-like activity. The overall response rate was 88% (95% confidence interval CI, 76 to 95); 39/57 patients (68%) achieved a complete response, 3/57 (5%) achieved a very good partial response, and 8/57 (14%) achieved a partial response. Minimal residual disease was negative for 36/57 (63%) patients. The median time to response was 1 month (range, 0.4 to 3.5). At a median follow-up of 8 months, median progression-free survival was 15 months (95% CI, 11 to not estimable). Median overall survival for all patients was not reached.
LCAR-B38M CAR T cell therapy displayed a manageable safety profile and demonstrated deep and durable responses in patients with R/R MM.
ClinicalTrials.gov , NCT03090659 ; Registered on March 27, 2017, retrospectively registered.
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