Increased vascular permeability facilitates metastasis. Emerging evidence indicates that secreted microRNAs (miRNAs) may mediate the crosstalk between cancer and stromal cells. To date, whether and ...how secreted miRNAs affect vascular permeability remains unclear. Based on deep sequencing and quantitative PCR, we found that higher level of serum miR‐103 was associated with higher metastasis potential of hepatocellular carcinoma (HCC). The in vitro endothelial permeability and transendothelial invasion assays revealed that the conditioned media or exosomes derived from high miR‐103‐expressing hepatoma cells increased the permeability of endothelial monolayers, but this effect was attenuated if exosome secretion of hepatoma cells was blocked by silencing ALIX and HRS or if miR‐103 within hepatoma or endothelial cells was antagonized. Most importantly, pretreating endothelial monolayers with exosomes that were from stable miR‐103‐expressing hepatoma cells facilitated the transendothelial invasion of tumor cells, and this role of exosomes was abrogated by inhibiting miR‐103 in endothelial cells. Further in vivo analyses disclosed that mice with xenografts of stable miR‐103‐expressing hepatoma cells exhibited higher vascular permeability in tumor, higher level of exosomal miR‐103 and greater number of tumor cells in blood circulation, and increased rates of hepatic and pulmonary metastases, compared to control mice. Mechanism investigations revealed that hepatoma cell‐secreted miR‐103 could be delivered into endothelial cells via exosomes, and then attenuated the endothelial junction integrity by directly inhibiting the expression of VE‐Cadherin (VE‐Cad), p120‐catenin (p120) and zonula occludens 1. Moreover, miR‐103 could also promote tumor cell migration by repressing p120 expression in hepatoma cells. Conclusion: Hepatoma cell‐secreted exosomal miR‐103 increases vascular permeability and promotes tumor metastasis by targeting multiple endothelial junction proteins, which highlights secreted miR‐103 as a potential therapeutic target and a predictive marker for HCC metastasis. (Hepatology 2018).
Macroautophagy (hereafter called autophagy) is a highly conserved physiological process that degrades over-abundant or damaged organelles, large protein aggregates and invading pathogens via the ...lysosomal system (the vacuole in plants and yeast). Autophagy is generally induced by stress, such as oxygen-, energy- or amino acid-deprivation, irradiation, drugs,
. In addition to non-selective bulk degradation, autophagy also occurs in a selective manner, recycling specific organelles, such as mitochondria, peroxisomes, ribosomes, endoplasmic reticulum (ER), lysosomes, nuclei, proteasomes and lipid droplets (LDs). This capability makes selective autophagy a major process in maintaining cellular homeostasis. The dysfunction of selective autophagy is implicated in neurodegenerative diseases (NDDs), tumorigenesis, metabolic disorders, heart failure,
. Considering the importance of selective autophagy in cell biology, we systemically review the recent advances in our understanding of this process and its regulatory mechanisms. We emphasize the 'cargo-ligand-receptor' model in selective autophagy for specific organelles or cellular components in yeast and mammals, with a focus on mitophagy and ER-phagy, which are finely described as types of selective autophagy. Additionally, we highlight unanswered questions in the field, helping readers focus on the research blind spots that need to be broken.
In plants, submergence from flooding causes hypoxia, which impairs energy production and affects plant growth, productivity, and survival. In Arabidopsis, hypoxia induces nuclear localization of the ...group VII ethylene‐responsive transcription factor RELATED TO AP2.12 (RAP2.12), following its dissociation from the plasma membrane‐anchored ACYL‐COA BINDING PROTEIN1 (ACBP1) and ACBP2. Here, we show that polyunsaturated linolenoyl‐CoA (18:3‐CoA) regulates RAP2.12 release from the plasma membrane. Submergence caused a significant increase in 18:3‐CoA, but a significant decrease in 18:0‐, 18:1‐, and 18:2‐CoA. Application of 18:3‐CoA promoted nuclear accumulation of the green fluorescent protein (GFP) fusions RAP2.12‐GFP, HYPOXIA‐RESPONSIVE ERF1‐GFP, and RAP2.3‐GFP, and enhanced transcript levels of hypoxia‐responsive genes. Plants with decreased ACBP1 and ACBP2 (acbp1 ACBP2‐RNAi, produced by ACBP2 RNA interference in the acbp1 mutant) had reduced tolerance to hypoxia and impaired 18:3‐CoA‐induced expression of hypoxia‐related genes. In knockout mutants and overexpression lines of LONG‐CHAIN ACYL‐COA SYNTHASE2 (LACS2) and FATTY ACID DESATURASE 3 (FAD3), the acyl‐CoA pool size and 18:3‐CoA levels were closely related to ERF‐VII‐mediated signaling and hypoxia tolerance. These findings demonstrate that polyunsaturation of long‐chain acyl‐CoAs functions as important mechanism in the regulation of plant hypoxia signaling, by modulating ACBP–ERF‐VII dynamics.
BES1 is a key transcription factor that antagonizes JA‐activated plant defense responses by directly suppressing the expression of defensing and GS biosynthesis genes in Arabidopsis.
During cancer therapy, phagocytic clearance of dead cells plays a vital role in immune homeostasis. The nonapoptotic form of cell death, ferroptosis, exhibits extraordinary potential in tumor ...treatment. However, the phagocytosis mechanism that regulates the engulfment of ferroptotic cells remains unclear. Here, we establish a novel pathway for phagocytic clearance of ferroptotic cells that is different from canonical mechanisms by using diverse ferroptosis models evoked by GPX4 dysfunction/deficiency. We identified the oxidized phospholipid, 1-steaoryl-2-15-HpETE-sn-glycero-3-phosphatidylethanolamine (SAPE-OOH), as a key eat-me signal on the ferroptotic cell surface. Enriching the plasma membrane with SAPE-OOH increased the efficiency of phagocytosis of ferroptotic cells by macrophage, a process that was suppressed by lipoprotein-associated phospholipase A
. Ligand fishing, lipid blotting, and cellular thermal shift assay screened and identified TLR2 as a membrane receptor that directly recognized SAPE-OOH, which was further confirmed by TLR2 inhibitors and gene silencing studies. A mouse mammary tumor model of ferroptosis verified SAPE-OOH and TLR2 as critical players in the clearance of ferroptotic cells in vivo. Taken together, this work demonstrates that SAPE-OOH on ferroptotic cell surface acts as an eat-me signal and navigates phagocytosis by targeting TLR2 on macrophages.
Inflammatory bowel disease (IBD) is an intestinal chronic inflammatory disease, and is related to imbalance of CD4
+
T subsets. However, the current treatments of chronic colitis are not ideal and ...have potential side effects. Therefore, more effective and safer biologically active substances which are extracted from natural plants have been widely concerned. In this study, it was found that Inonotus obliquus polysaccharides (IOP), the main bioactive constituent of Inonotus obliquus, can alleviate dextran sodium sulfate-induced chronic murine intestinal inflammation. Oral administration of IOP (100, 200, 300 mg/kg) can significantly reduce the disease active index and alleviate the pathological changes in colitis mice, where the tight junction proteins Occludin and ZO-1 losses in colon tissues were reduced. It can also regulate imbalanced Th1/Th2 and Th17/Treg in colon tissues, mesenteric lymph nodes and spleen using Reverse Transcription-Polymerase Chain Reaction detection and flow cytometry. Immunohistochemistry and western blot assays further revealed the modulatory effect of IOP on the p-STAT1, p-STAT6, p-STAT3 expression, which promoted the balance of Th1/Th2, Th17/Treg in the colon of chronic colitis mice. In short, these results indicated that IOP was potentially effective therapeutic agent for IBD.
The development of electrocatalysts capable of efficient reduction of nitrate (NO
) to ammonia (NH
) is drawing increasing interest for the sake of low carbon emission and environmental protection. ...Herein, we present a CuCo bimetallic catalyst able to imitate the bifunctional nature of copper-type nitrite reductase, which could easily remove NO
via the collaboration of two active centers. Indeed, Co acts as an electron/proton donating center, while Cu facilitates NO
adsorption/association. The bio-inspired CuCo nanosheet electrocatalyst delivers a 100 ± 1% Faradaic efficiency at an ampere-level current density of 1035 mA cm
at -0.2 V vs. Reversible Hydrogen Electrode. The NH
production rate reaches a high activity of 4.8 mmol cm
h
(960 mmol g
h
). A mechanistic study, using electrochemical in situ Fourier transform infrared spectroscopy and shell-isolated nanoparticle enhanced Raman spectroscopy, reveals a strong synergy between Cu and Co, with Co sites promoting the hydrogenation of NO
to NH
via adsorbed *H species. The well-modulated coverage of adsorbed *H and *NO
led simultaneously to high NH
selectivity and yield.
Severe COVID-19 disease caused by SARS-CoV-2 is frequently accompanied by dysfunction of the lungs and extrapulmonary organs. However, the organotropism of SARS-CoV-2 and the port of virus entry for ...systemic dissemination remain largely unknown. We profiled 26 COVID-19 autopsy cases from four cohorts in Wuhan, China, and determined the systemic distribution of SARS-CoV-2. SARS-CoV-2 was detected in the lungs and multiple extrapulmonary organs of critically ill COVID-19 patients up to 67 days after symptom onset. Based on organotropism and pathological features of the patients, COVID-19 was divided into viral intrapulmonary and systemic subtypes. In patients with systemic viral distribution, SARS-CoV-2 was detected in monocytes, macrophages, and vascular endothelia at blood-air barrier, blood-testis barrier, and filtration barrier. Critically ill patients with long disease duration showed decreased pulmonary cell proliferation, reduced viral RNA, and marked fibrosis in the lungs. Permanent SARS-CoV-2 presence and tissue injuries in the lungs and extrapulmonary organs suggest direct viral invasion as a mechanism of pathogenicity in critically ill patients. SARS-CoV-2 may hijack monocytes, macrophages, and vascular endothelia at physiological barriers as the ports of entry for systemic dissemination. Our study thus delineates systemic pathological features of SARS-CoV-2 infection, which sheds light on the development of novel COVID-19 treatment.
Summary
Submergence is an abiotic stress that limits agricultural production world‐wide. Plants sense oxygen levels during submergence and postsubmergence reoxygenation and modulate their responses. ...Increasing evidence suggests that completely submerged plants are often exposed to low‐light stress, owing to the depth and turbidity of the surrounding water; however, how light availability affects submergence tolerance remains largely unknown.
Here, we showed that Arabidopsis thaliana MYB DOMAIN PROTEIN30 (MYB30) is an important transcription factor that integrates light signaling and postsubmergence stress responses.
MYB DOMAIN PROTEIN30 protein abundance decreased upon submergence and accumulated during reoxygenation. Under submergence conditions, CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), a central regulator of light signaling, caused the ubiquitination and degradation of MYB30. In response to desubmergence, however, light‐induced MYB30 interacted with MYC2, a master transcription factor involved in jasmonate signaling, and activated the expression of the VITAMIN C DEFECTIVE1 (VTC1) and GLUTATHIONE SYNTHETASE1 (GSH1) gene families to enhance antioxidant biosynthesis. Consistent with this, the myb30 knockout mutant showed increased sensitivity to submergence, which was partially rescued by overexpression of VTC1 or GSH1.
Thus, our findings uncover the mechanism by which the COP1‐MYB30 module integrates light signals with cellular oxidative homeostasis to coordinate plant responses to postsubmergence stress.
The design of efficient catalysts capable of delivering high currents at low overpotentials for hydrogen evolution reactions (HERs) is urgently needed to use catalysts in practical applications. ...Herein, we report platinum (Pt) alloyed with titanium (Ti) from the surface of Ti3C2T x MXenes to form Pt3Ti intermetallic compound (IMC) nanoparticles (NPs) via in situ coreduction. In situ X-ray absorption spectroscopy (XAS) indicates that Pt undergoes a temperature-dependent transformation from single atoms to intermetallic compounds, and the catalyst reduced at 550 °C exhibits a superior HER performance in acidic media. The Pt/Ti3C2T x -550 catalyst outperforms commercial Pt/Vulcan and has a small overpotential of 32.7 mV at 10 mA cm–2 and a low Tafel slope of 32.3 mV dec–1. The HER current was normalized by the mass and dispersion of Pt, and the mass activity and specific activity of Pt/Ti3C2T x -550 are 4.4 and 13 times higher, respectively, than those of Pt/Vulcan at an overpotential of 70 mV. The density functional theory (DFT) calculations suggest that the (111)- and (100)-terminated Pt3Ti nanoparticles exhibit *H binding comparable to Pt(111), while the (110) termination has an *H adsorption that is too exergonic, thus poisoned in the low overpotential region. This work demonstrates the potential of MXenes as platforms for the design of electrocatalysts and may spur future research for other MXene-supported metal catalysts that can be used for a wide range of electrocatalytic reactions.
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