[Research progress of celastrol on the prevention and treatment of metabolic associated fatty liver disease].

Metabolic associated fatty liver disease (MAFLD) is a liver disease with hepatocyte steatosis caused by metabolic disorders, which is closely related to obesity, diabetes, metabolic dysfunction, and other factors. Its pathological process changes from simple steatosis, liver inflammation to non-alcoholic steatohepatitis (NASH), and then leads to liver fibrosis, cirrhosis, and liver cancer. At present, no specific therapeutics are available for treatment of MAFLD targeting its etiology. Celastrol is the main active component of the traditional Chinese medicine Celastrus orbiculatus Thunb. In recent years, it has been found that celastrol shows important medicinal value in regulating lipid metabolism, reducing fat and weight, and protecting liver, and then ameliorates MAFLD. This article reviews the related research progress of celastrol in the prevention and treatment of MAFLD, so as to provide a reference for the comprehensive development and utilization of celastrol.

A strategy of local hydrogen capture and catalytic hydrogenation for enhanced therapy of chronic liver diseases.

Background: Chronic liver diseases (CLD) frequently derive from hepatic steatosis, inflammation and fibrosis, and become a leading inducement of cirrhosis and hepatocarcinoma. Molecular hydrogen (H2) is an emerging wide-spectrum anti-inflammatory molecule which is able to improve hepatic inflammation and metabolic dysfunction, and holds obvious advantages in biosafety over traditional anti-CLD drugs, but existing H2 administration routes cannot realize the liver-targeted high-dose delivery of H2, severely limiting its anti-CLD efficacy. Method: In this work, a concept of local hydrogen capture and catalytic hydroxyl radical (·OH) hydrogenation is proposed for CLD treatment. The mild and moderate non-alcoholic steatohepatitis (NASH) model mice were intravenously injected with PdH nanoparticles firstly, and then daily inhaled 4% hydrogen gas for 3 h throughout the whole treatment period. After the end of treatment, glutathione (GSH) was intramuscularly injected every day to assist the Pd excretion. Results: In vitro and in vivo proof-of-concept experiments have confirmed that Pd nanoparticles can accumulate in liver in a targeted manner post intravenous injection, and play a dual role of hydrogen captor and ·OH filter to locally capture/store the liver-passing H2 during daily hydrogen gas inhalation and rapidly catalyze the ·OH hydrogenation into H2O. The proposed therapy significantly improves the outcomes of hydrogen therapy in the prevention and treatment of NASH by exhibiting a wide range of bioactivity including the regulation of lipid metabolism and anti-inflammation. Pd can be mostly eliminated after the end of treatment under the assistance of GSH. Conclusion: Our study verified a catalytic strategy of combining PdH nanoparticles and hydrogen inhalation, which exhibited enhanced anti-inflammatory effect for CLD treatment. The proposed catalytic strategy will open a new window to realize safe and efficient CLD treatment.

PCK1 activates oncogenic autophagy via down-regulation Serine phosphorylation of UBAP2L and antagonizes colorectal cancer growth.

Phosphoenolpyruvate carboxykinase 1 (PCK1) is the rate-limiting enzyme in gluconeogenesis. PCK1 is considered an anti-oncogene in several human cancers. In this study, we aimed to determine the functions of PCK1 in colorectal cancer (CRC). PCK1 expression in CRC tissues was tested by western blot and immunohistochemistry analyses and associations of PCK1 level with clinicopathological characteristics and disease survival evaluated. Further, we studied the effect of PCK1 on CRC cell proliferation and the underlying mechanisms. Our results show that PCK1 is expressed at significantly lower levels in CRC than in control tissues. High PCK1 expression was correlated with smaller tumor diameter and less bowel wall invasion (T stage). Overexpression and knockdown experiments demonstrated that PCK1 inhibits CRC cell growth both in vitro and in vivo. Mechanistically, PCK1 antagonizes CRC growth via inactivating UBAP2L phosphorylation at serine 454 and enhancing autophagy. Overall, our findings reveal a novel molecular mechanism involving PCK1 and autophagy, and highlight PCK1 as a promising candidate therapeutic target in CRC.

Elevated cholesteryl ester transfer and phospholipid transfer proteins aggravated psoriasis in imiquimod-induced mouse models.

BACKGROUND: Psoriasis is a chronic inflammatory skin disorder related to dyslipidemia, with decreased high-density lipoprotein (HDL). Various cell types express phospholipid transfer protein (PLTP) as well as cholesteryl ester transfer protein (CETP). Their elevated levels among transgenic (Tg) mice led to reduced HDL and a higher risk of atherosclerosis (AS). This study examined whether elevated CETP and PLTP could aggravate psoriasis in a psoriasis vulgaris mouse model. METHODS: The back skins of CETP-Tg, PLTP-Tg, and C57BL/6 male mice, aged six to 8 weeks, were shaved for imiquimod cream (IMQ) (5%) treatment for five consecutive days. The clinical pathological parameters were rated independently using the modified target lesion psoriasis severity score. The skin sections stained with hematoxylin-eosin were scored by the Baker score. Epidermal thickening and differentiation and inflammatory factor infiltration were determined by immunohistochemistry. Inflammatory cytokine levels were measured using quantitative reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) kits. This work employed SPSS Statistics Version to conduct statistical analyses. RESULTS: In this study, CETP-Tg and PLTP-Tg mice had higher clinical and histological scores than wild-type (WT) mice. Immunohistochemistry of the epidermis and dermis revealed a high proportion of proliferating cell nuclear antigen (PCNA) positivity within psoriatic skin lesions of CETP-Tg and PLTP-Tg mice compared with WT mice. Interferon-α (IFN-α), interleukin-1ß (IL-1ß), IL-6, IL-17A, IL-17F, IL-22, and IL-23p19 mRNA levels increased within CETP-Tg and PLTP-Tg mice compared with WT counterparts. In comparison with WT mice, plasma tumor necrosis factor-α (TNF-α) levels, rather than IL-6 levels, were increased in CETP-Tg and PLTP-Tg mice. CONCLUSIONS: Elevated CETP and PLTP aggravate psoriasis in a imiquimod-induced mouse model.

The role of hepatic Surf4 in lipoprotein metabolism and the development of atherosclerosis in apoE-/- mice.

Elevated plasma levels of low-density lipoprotein-C (LDL-C) increase the risk of atherosclerotic cardiovascular disease. Circulating LDL is derived from very low-density lipoprotein (VLDL) metabolism and cleared by LDL receptor (LDLR). We have previously demonstrated that cargo receptor Surfeit 4 (Surf4) mediates VLDL secretion. Inhibition of hepatic Surf4 impairs VLDL secretion, significantly reduces plasma LDL-C levels, and markedly mitigates the development of atherosclerosis in LDLR knockout (Ldlr-/-) mice. Here, we investigated the role of Surf4 in lipoprotein metabolism and the development of atherosclerosis in another commonly used mouse model of atherosclerosis, apolipoprotein E knockout (apoE-/-) mice. Adeno-associated viral shRNA was used to silence Surf4 expression mainly in the liver of apoE-/- mice. In apoE-/- mice fed a regular chow diet, knockdown of Surf4 expression significantly reduced triglyceride secretion and plasma levels of non-HDL cholesterol and triglycerides without causing hepatic lipid accumulation or liver damage. When Surf4 was knocked down in apoE-/- mice fed the Western-type diet, we observed a significant reduction in plasma levels of non-HDL cholesterol, but not triglycerides. Knockdown of Surf4 did not increase hepatic cholesterol and triglyceride levels or cause liver damage, but significantly diminished atherosclerosis lesions. Therefore, our findings indicate the potential of hepatic Surf4 inhibition as a novel therapeutic strategy to reduce the risk of atherosclerotic cardiovascular disease.

A randomized, placebo-controlled clinical trial of hydrogen/oxygen inhalation for non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide with increasing incidence consistent with obesity, type 2 diabetes and cardiovascular diseases. No approved medication was currently available for NAFLD treatment. Molecular hydrogen (H2 ), an anti-oxidative, anti-inflammatory biomedical agent is proved to exhibit therapeutic and preventive effect in various diseases. The purpose of this study was to investigate the effect of hydrogen/oxygen inhalation on NAFLD subjects and explore the mechanism from the perspective of hepatocyte autophagy. We conducted a randomized, placebo-controlled clinical trial of 13-week hydrogen/oxygen inhalation (China Clinical Trial Registry [#ChiCTR-IIR-16009114]) including 43 subjects. We found that inhalation of hydrogen/oxygen improved serum lipid and liver enzymes. Significantly improved liver fat content detected by ultrasound and CT scans after hydrogen/oxygen inhalation was observed in moderate-severe cases. We also performed an animal experiment based on methionine and choline-deficient (MCD) diet-induced mice model to investigate effect of hydrogen on mouse NASH. Hydrogen/oxygen inhalation improved systemic inflammation and liver histology. Promoted autophagy was observed in mice inhaled hydrogen/oxygen and treatment with chloroquine blocked the beneficial effect of hydrogen. Moreover, molecular hydrogen inhibited lipid accumulation in AML-12 cells. Autophagy induced by palmitic acid (PA) incubation was further promoted by 20% hydrogen incubation. Addition of 3-methyladenine (3-MA) partially blocked the inhibitory effect of hydrogen on intracellular lipid accumulation. Collectively, hydrogen/oxygen inhalation alleviated NAFLD in moderate-severe patients. This protective effect of hydrogen was possibly by activating hepatic autophagy.

Molecular Hydrogen Inhibits Colorectal Cancer Growth via the AKT/SCD1 Signaling Pathway.

Objective: Molecular hydrogen (H2) has been considered a potential therapeutic target in many cancers. Therefore, we sought to assess the potential effect of H2 on colorectal cancer (CRC) in this study. Methods: The effect of H2 on the proliferation and apoptosis of RKO, SW480, and HCT116 CRC cell lines was assayed by CCK-8, colony formation, and flow cytometry assays. The effect of H2 on tumor growth was observed in xenograft implantation models (inhalation of 67% hydrogen two hours per day). Western blot and immunohistochemistry analyses were performed to examine the expression of p-PI3K, PI3K, AKT, pAKT, and SCD1 in CRC cell lines and xenograft mouse models. The expression of SCD1 in 491 formalin-fixed, paraffin-embedded CRC specimens was investigated with immunochemistry. The relationship between SCD1 status and clinicopathological characteristics and outcomes was determined. Results: Hydrogen treatment suppressed the proliferation of CRC cell lines independent of apoptosis, and the cell lines showed different responses to different doses of H2. Hydrogen also elicited a potent antitumor effect to reduce CRC tumor volume and weight in vivo. Western blot and IHC staining demonstrated that H2 inhibits CRC cell proliferation by decreasing pAKT/SCD1 levels, and the inhibition of cell proliferation induced by H2 was reversed by the AKT activator SC79. IHC showed that SCD1 expression was significantly higher in CRC tissues than in normal epithelial tissues (70.3% vs. 29.7%, p = 0.02) and was correlated with a more advanced TNM stage (III vs. I + II; 75.9% vs. 66.3%, p = 0.02), lymph node metastasis (with vs. without; 75.9% vs. 66.3%, p = 0.02), and patients without a family history of CRC (78.7% vs. 62.1%, p = 0.047). Conclusion: This study demonstrates that high concentrations of H2 exert an inhibitory effect on CRC by inhibiting the pAKT/SCD1 pathway. Further studies are warranted for clinical evaluation of H2 as SCD1 inhibitor to target CRC.

Acid-Degradable Hydrogen-Generating Metal-Organic Framework for Overcoming Cancer Resistance/Metastasis and Off-Target Side Effects.

The development of stimuli-responsively degradable porous carriers for both controlled drug release and high biosafety is vitally important to their clinical translation, but still challenging at present. A new type of porphyrin-iron metal organic framework (Fe-MOF) nanocrystals is engineered here as acid-degradable drug carrier and hydrogen donor by the coordination between porphyrin and zero-valence Fe atom. Fe-MOF nanocrystals exhibit excellent acid-responsive degradation for H2 generation and simultaneous release of the loaded drug for combined hydrogen-chemotherapy of cancer multidrug resistance (MDR) and metastasis and for local hydrogen eradication of the off-target induced toxic side effects of the drug to normal cells/tissues. Mechanistically, released H2 assists chemotherapeutic drug to efficiently inhibit cancer metastasis by immunoactivating intratumoral M1-phenotype macrophages and consequently downregulating the expression of metastasis-related matrix metalloproteinase-2 (MMP-2) and can also downregulate the expressions of both P-glycoprotein (P-gp) protein and adenosine triphosphate (ATP) in MDR cancer cells to sensitize chemotherapeutic drug for enhanced damage to mitochondria and DNA. High anti-MDR/antimetastasis efficacies and high biocompatibility endow Fe-MOF nanocrystals and the Fe-MOF-based nanomedicine with high potential for clinical translation.

In vivo microelectrode monitoring of real-time hydrogen concentration in different tissues of rats after inhaling hydrogen gas.

Medical effects of hydrogen have been reported in many studies. Due to difficulties in measuring hydrogen concentration in vivo after intake and high explosive risks of hydrogen, studies about dose-response relationships and tissue concentrations of hydrogen are few. Here, for the first time, we monitored real-time hydrogen concentrations in different tissues in rats including brain, liver, spleen, kidney, thigh muscle, inguinal white adipose tissue, and gonadal white adipose tissue after inhaling different concentrations of hydrogen (4%, 42%, and 67%) using an electrochemical sensor. Hydrogen concentrations in the same tissue showed a dose-dependent response. The equilibrium concentration values were highest in the brain and lowest in the thigh muscle. The saturation and desaturation curves changed more slowly in the thigh muscle and white adipose tissues than in other tissues. These results provide fundamental information for the selection of hydrogen dose applications in basic research and clinical trials. The experiments were approved by the Laboratory Animal Ethics Committee of Shandong First Medical University & Shandong Academy of Medical Sciences (No. 2020-1028) on March 18, 2020.

Protective Effect of Molecular Hydrogen Following Different Routes of Administration on D-Galactose-Induced Aging Mice.

BACKGROUND: Molecular hydrogen (H2) has been recognized as an effective antioxidant with no or little side effects. While it is known that oxidative stress is closely associated with aging, the beneficial effect of H2 on oxidative stress-related aging is still unclear. In this study, a mouse model of D-galactose-induced aging was employed to investigate the protective effects of H2. METHODS: The mice were administrated of H2 via different routes (4% H2 inhalation, H2-rich water drinking, and H2-rich saline injection), the aging-related biomarkers in plasma and the oxidative stress in different tissues were measured. RESULTS: The results showed that H2 improved aging-related biomarkers, ie, total antioxidant capacity, advanced glycation end products, tumor necrosis factor-α, free fatty acids, and alanine aminotransferase in plasma. Furthermore, H2 alleviated oxidative stress in the liver, brain, and heart by reducing the levels of lipid peroxidation and malondialdehyde and increasing the activity of superoxide dismutase. In addition, it seems that 4% H2 inhalation was the most effective regarding the amount of H2 taken up and in reducing the markers of oxidative stress in some of the tissues; however, the other routes of administration resulted in the same efficacy in most indicators. CONCLUSION: H2 can prevent oxidative stress in D-galactose-induced aging mice when administered by different routes.

D4F alleviates the C/EBP homologous protein-mediated apoptosis in glycated high-density lipoprotein-treated macrophages by facilitating autophagy.

The present study aimed to investigate the role of D4F, an apolipoprotein A-I mimetic peptide, in macrophage apoptosis induced by the glycated high-density lipoprotein (gly-HDL)-induced endoplasmic reticulum (ER) stress C/EBP homologous protein (CHOP) pathway, and unravel the regulatory role of autophagy in this process. Our results revealed that except for suppressing the accumulation of lipids within RAW264.7 macrophages caused by gly-HDL, D4F inhibited gly-HDL-induced decrease in the cell viability and increase in lactate dehydrogenase leakage and cell apoptosis, which were similar to 4-phenylbutyric acid (PBA, an ER stress inhibitor). Besides, similar to PBA, D4F inhibited gly-HDL-induced ER stress response activation evaluated through the decreased PERK and eIF2α phosphorylation, together with reduced ATF6 nuclear translocation as well as the downregulation of GRP78 and CHOP. Interestingly, D4F facilitated gly-HDL-triggered activation of autophagy, measured as elevated levels of beclin-1, LC3-II, and ATG5 expressions in macrophages. Furthermore, the inhibition effect of D4F on gly-HDL-induced ER stress-CHOP-induced apoptosis of macrophages was restrained after beclin-1 siRNA and 3-methyladenine (3-MA, an inhibitor of autophagy) treatments, while this effect was further reinforced after rapamycin (Rapa, an inducer of autophagy) treatment. Furthermore, administering D4F or Rapa to T2DM mice upregulated LC3-II and attenuated CHOP expression, cell apoptosis, and atherosclerotic lesions. However, the opposite results were obtained when 3-MA was administered to these mice. These results support that D4F effectively protects macrophages against gly-HDL-induced ER stress-CHOP-mediated apoptosis by promoting autophagy.

Human cholesteryl ester transport protein transgene promotes macrophage reverse cholesterol transport in C57BL/6 mice and phospholipid transfer protein gene knockout mice.

Cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP) belong to the same gene family. Liver-specific expression of CETP improves reverse cholesterol transport (RCT) and PLTP knockout (KO) decreases RCT in mice. In this study, we investigate the effect of CETP transgene (CETP-tg) on RCT and whether CETP-tg can partially restore RCT efficiency in PLTP KO mice. Several rounds of crossing were carried out to produce colonies of wild type (WT), CETP-tg, PLTP KO, and CETP-tg × PLTP KO mice were obtained after several generations of reproduction. The efficiency of RCT was detected using [3H]-cholesterol-laden macrophages, and the underlying mechanisms were investigated by multiple techniques. Our data demonstrated that CETP-tg significantly increased the transport rate of [3H]-cholesterol from macrophages to plasma and liver, and finally the excretion through feces compared to the WT littermates. The RCT improving effect of CETP-tg was similar in PLTPKO mice. Furthermore, CETP-tg did not affect the expression of RCT-related proteins, such as low-density lipoprotein receptor. The mechanisms of improving RCT may be attributed to the low level of oxidized lipids in CETP-tg mouse and CETP-mediated lipid transport. Collectively, CETP-tg improves RCT in mice, and CETP can not compensate for PLTP deficiency.

Membrane type 1 matrix metalloproteinase promotes LDL receptor shedding and accelerates the development of atherosclerosis.

Plasma low-density lipoprotein (LDL) is primarily cleared by LDL receptor (LDLR). LDLR can be proteolytically cleaved to release its soluble ectodomain (sLDLR) into extracellular milieu. However, the proteinase responsible for LDLR cleavage is unknown. Here we report that membrane type 1-matrix metalloproteinase (MT1-MMP) co-immunoprecipitates and co-localizes with LDLR and promotes LDLR cleavage. Plasma sLDLR and cholesterol levels are reduced while hepatic LDLR is increased in mice lacking hepatic MT1-MMP. Opposite effects are observed when MT1-MMP is overexpressed. MT1-MMP overexpression significantly increases atherosclerotic lesions, while MT1-MMP knockdown significantly reduces cholesteryl ester accumulation in the aortas of apolipoprotein E (apoE) knockout mice. Furthermore, sLDLR is associated with apoB and apoE-containing lipoproteins in mouse and human plasma. Plasma levels of sLDLR are significantly increased in subjects with high plasma LDL cholesterol levels. Thus, we demonstrate that MT1-MMP promotes ectodomain shedding of hepatic LDLR, thereby regulating plasma cholesterol levels and the development of atherosclerosis.

Neuroprotective Effects of Molecular Hydrogen: A Critical Review.

Molecular hydrogen (H2) is a physiologically inert gas. However, during the last 10 years, increasing evidence has revealed its biological functions under pathological conditions. More specifically, H2 has protective effects against a variety of diseases, particularly nervous system disorders, which include ischemia/reperfusion injury, traumatic injury, subarachnoid hemorrhage, neuropathic pain, neurodegenerative diseases, cognitive dysfunction induced by surgery and anesthesia, anxiety, and depression. In addition, H2 plays protective roles mainly through anti-oxidation, anti-inflammation, anti-apoptosis, the regulation of autophagy, and preservation of mitochondrial function and the blood-brain barrier. Further, H2 is easy to use and has neuroprotective effects with no major side-effects, indicating that H2 administration is a potential therapeutic strategy in clinical settings. Here we summarize the H2 donors and their pharmacokinetics. Meanwhile, we review the effectiveness and safety of H2 in the treatment of various nervous system diseases based on preclinical and clinical studies, leading to the conclusion that H2 can be a simple and effective clinical therapy for CNS diseases such as ischemia-reperfusion brain injury, Parkinson's disease, and diseases characterized by cognitive dysfunction. The potential mechanisms involved in the neuroprotective effect of H2 are also analyzed.

Molecular hydrogen: current knowledge on mechanism in alleviating free radical damage and diseases.

Ever since molecular hydrogen was first reported as a hydroxyl radical scavenger in 2007, the beneficial effect of hydrogen was documented in more than 170 disease models and human diseases including ischemia/reperfusion injury, metabolic syndrome, inflammation, and cancer. All these pathological damages are concomitant with overproduction of reactive oxygen species (ROS) where molecular hydrogen has been widely demonstrated as a selective antioxidant. Although it is difficult to construe the molecular mechanism of hydrogen's biomedical effect, an increasing number of studies have been helping us draw the picture clearer with days passing by. In this review, we summarized the current knowledge on systemic and cellular modulation by hydrogen treatment. We discussed the antioxidative, anti-inflammatory, and anti-apoptosis effects of hydrogen, as well as its protection on mitochondria and the endoplasmic reticulum, regulation of intracellular signaling pathways, and balancing of the immune cell subtypes. We hope that this review will provide organized information that prompts further investigation for in-depth studies of hydrogen effect.

"Real world survey" of hydrogen-controlled cancer: a follow-up report of 82 advanced cancer patients.

Advanced cancer treatment is a huge challenge and new ideas and strategies are required. Hydrogen exerts antioxidant and anti-inflammatory effects that may be exploited to control cancer, the occurrence and progression of which is closely related to peroxidation and inflammation. We conducted a prospective follow-up study of 82 patients with stage III and IV cancer treated with hydrogen inhalation using the "real world evidence" method. After 3-46 months of follow-up, 12 patients died in stage IV. After 4 weeks of hydrogen inhalation, patients reported significant improvements in fatigue, insomnia, anorexia and pain. Furthermore, 41.5% of patients had improved physical status, with the best effect achieved in lung cancer patients and the poorest in patients with pancreatic and gynecologic cancers. Of the 58 cases with one or more abnormal tumor markers elevated, the markers were decreased at 13-45 days (median 23 days) after hydrogen inhalation in 36.2%. The greatest marker decrease was in achieved lung cancer and the lowest in pancreatic and hepatic malignancies. Of the 80 cases with tumors visible in imaging, the total disease control rate was 57.5%, with complete and partial remission appearing at 21-80 days (median 55 days) after hydrogen inhalation. The disease control rate was significantly higher in stage III patients than in stage IV patients (83.0% and 47.7%, respectively), with the lowest disease control rate in pancreatic cancer patients. No hematological toxicity was observed although minor adverse reactions that resolved spontaneously were seen in individual cases. In patients with advanced cancer, inhaled hydrogen can improve patients' quality-of-life and control cancer progression. Hydrogen inhalation is a simple, low-cost treatment with few adverse reactions that warrants further investigation as a strategy for clinical rehabilitation of patients with advanced cancer. The study protocol received ethical approval from the Ethics Committee of Fuda Cancer Hospital of Jinan University on December 7, 2018 (approval number: Fuda20181207).

Reverse-D-4F improves endothelial progenitor cell function and attenuates LPS-induced acute lung injury.

BACKGROUND: Patients with acute lung injury (ALI) have increased levels of pro-inflammatory mediators, which impair endothelial progenitor cell (EPC) function. Increasing the number of EPC and alleviating EPC dysfunction induced by pro-inflammatory mediators play important roles in suppressing ALI development. Because the high density lipoprotein reverse-D-4F (Rev-D4F) improves EPC function, we hypothesized that it might repair lipopolysaccharide (LPS)-induced lung damage by improving EPC numbers and function in an LPS-induced ALI mouse model. METHODS: LPS was used to induce ALI in mice, and then the mice received intraperitoneal injections of Rev-D4F. Immunohistochemical staining, flow cytometry, MTT, transwell, and western blotting were used to assess the effect of Rev-D4F on repairment of lung impairment, and improvement of EPC numbers and function, as well as the signaling pathways involved. RESULTS: Rev-D4F inhibits LPS-induced pulmonary edema and decreases plasma levels of the pro-inflammatory mediators TNF-α and ET-1 in ALI mice. Rev-D4F inhibited infiltration of red and white blood cells into the interstitial space, reduced lung injury-induced inflammation, and restored injured pulmonary capillary endothelial cells. In addition, Rev-D4F increased numbers of circulating EPC, stimulated EPC differentiation, and improved EPC function impaired by LPS. Rev-D4F also acted via a PI3-kinase-dependent mechanism to restore levels of phospho-AKT, eNOS, and phospho-eNOS suppressed by LPS. CONCLUSIONS: These findings indicate that Rev-D4F has an important vasculoprotective role in ALI by improving the EPC numbers and functions, and Rev-D4F reverses LPS-induced EPC dysfuncion partially through PI3K/AKT/eNOS signaling pathway.

Endoplasmic reticulum stress-dependent autophagy inhibits glycated high-density lipoprotein-induced macrophage apoptosis by inhibiting CHOP pathway.

This study was designed to explore the inductive effect of glycated high-density lipoprotein (gly-HDL) on endoplasmic reticulum (ER) stress-C/EBP homologous protein (CHOP)-mediated macrophage apoptosis and its relationship with autophagy. Our results showed that gly-HDL caused macrophage apoptosis with concomitant activation of ER stress pathway, including nuclear translocation of activating transcription factor 6, phosphorylation of protein kinase-like ER kinase (PERK) and eukaryotic translation initiation factor 2α, and CHOP up-regulation, which were inhibited by 4-phenylbutyric acid (PBA, an ER stress inhibitor) and the gene silencing of PERK and CHOP. Similar data were obtained from macrophages treated by HDL isolated from diabetic patients. Gly-HDL induced macrophage autophagy as assessed by up-regulation of beclin-1, autophagy-related gene 5 and microtubule-associated protein one light chain 3-II, which were depressed by PBA and PERK siRNA. Gly-HDL-induced apoptosis, PERK phosphorylation and CHOP up-regulation were suppressed by rapamycin (an autophagy inducer), whereas aggravated by 3-methyladenine (an autophagy inhibitor) and beclin-1 siRNA. Administration of diabetic apoE-/- mice with rapamycin attenuated MOMA-2 and CHOP up-regulation and apoptosis in atherosclerotic lesions. These data indicate that gly-HDL may induce macrophage apoptosis through activating ER stress-CHOP pathway and ER stress mediates gly-HDL-induced autophagy, which in turn protects macrophages against apoptosis by alleviating CHOP pathway.

Plasma Phospholipid Transfer Protein Promotes Platelet Aggregation.

It remains unclear whether plasma phospholipid transfer protein (PLTP) is involved in hyper-coagulation or hypo-coagulation. This study investigated the direct effect of PLTP on platelet aggregation and the underlying mechanism. Washed platelets from humans or mice and mouse platelet-rich plasma and human recombinant PLTP were isolated. PLTP is present in human platelets. We assessed adenosine diphosphate (ADP)-, collagen- and thrombin-induced platelet aggregation, phosphatidylserine externalization and photothrombosis-induced cerebral infarction in mice. PLTP over-expression increased platelet aggregation, while PLTP deficiency had the opposing reaction. Human recombinant PLTP increased both mouse and human platelet aggregation in a dose-dependent manner. Phosphatidylserine externalization provides a water/lipid surface for the interaction of coagulation factors, which accelerates thrombosis. Compared with wild-type controls, platelets from PLTP transgenic mice had significantly more phosphatidylserine on the exterior surface of the plasma membrane, whereas platelets from PLTP-deficient mice had significantly less phosphatidylserine on the surface, thus PLTP influences fibrinogen binding on the plasma membrane. Moreover, recombinant PLTP together with ADP significantly increased phosphatidylserine exposure on the plasma membrane of PLTP-deficient platelets, thereby increasing fibrinogen binding. PLTP over-expression significantly accelerated the incidence of photothrombosis-induced infarction in mice, whereas PLTP deficiency significantly reduced the frequency of infarction. We concluded that PLTP promotes phosphatidylserine externalization at the plasma membrane of platelets and accelerates ADP- or collagen-induced platelet aggregation. This effect plays an important role in the initiation of thrombin generation and platelet aggregation under sheer stress conditions. Thus, PLTP is involved in hyper-coagulation. Therefore, PLTP inhibition could be a novel approach for countering thrombosis.