Recent Advances in Understanding Multi-scale Climate Variability of the Asian Monsoon.

Studies of the multi-scale climate variability of the Asian monsoon are essential to an advanced understanding of the physical processes of the global climate system. In this paper, the progress achieved in this field is systematically reviewed, with a focus on the past several years. The achievements are summarized into the following topics: (1) the onset of the South China Sea summer monsoon; (2) the East Asian summer monsoon; (3) the East Asian winter monsoon; and (4) the Indian summer monsoon. Specifically, new results are highlighted, including the advanced or delayed local monsoon onset tending to be synchronized over the Arabian Sea, Bay of Bengal, Indochina Peninsula, and South China Sea; the basic features of the record-breaking mei-yu in 2020, which have been extensively investigated with an emphasis on the role of multi-scale processes; the recovery of the East Asian winter monsoon intensity after the early 2000s in the presence of continuing greenhouse gas emissions, which is believed to have been dominated by internal climate variability (mostly the Arctic Oscillation); and the accelerated warming over South Asia, which exceeded the tropical Indian Ocean warming, is considered to be the main driver of the Indian summer monsoon rainfall recovery since 1999. A brief summary is provided in the final section along with some further discussion on future research directions regarding our understanding of the Asian monsoon variability.

Activation of Piezo1 promotes osteogenic differentiation of aortic valve interstitial cell through YAP-dependent glutaminolysis.

Hemodynamic overload and dysregulation of cellular metabolism are involved in development of calcific aortic valve disease (CAVD). However, how mechanical stress relates to metabolic changes in CAVD remains unclear. Here, we show that Piezo1, a mechanosensitive ion channel, regulated glutaminase 1 (GLS1)-mediated glutaminolysis to promote osteogenic differentiation of valve interstitial cells (VICs). In vivo, two models of aortic valve stenosis were constructed by ascending aortic constriction (AAC) and direct wire injury (DWI). Inhibition of Piezo1 and GLS1 in these models respectively mitigated aortic valve lesion. In vitro, Piezo1 activation induced by Yoda1 and oscillatory stress triggered osteogenic responses in VICs, which were prevented by Piezo1 inhibition or knockdown. Mechanistically, Piezo1 activation promoted calcium-dependent Yes-associated protein (YAP) activation. YAP modulated GLS1-mediated glutaminolysis, which enhanced osteogenic differentiation through histone acetylation of runt-related transcription factor 2 (RUNX2) promoters. Together, our work provided a cross-talk between mechanotransduction and metabolism in the context of CAVD.

Hesperetin, a Promising Dietary Supplement for Preventing the Development of Calcific Aortic Valve Disease.

BACKGROUND: No effective therapeutic agents for calcific aortic valve disease (CAVD) are available currently. Dietary supplementation has been proposed as a novel treatment modality for various diseases. As a flavanone, hesperetin is widely abundant in citrus fruits and has been proven to exert protective effects in multiple diseases. However, the role of hesperetin in CAVD remains unclear. METHODS: Human aortic valve interstitial cells (VICs) were isolated from aortic valve leaflets. A mouse model of aortic valve stenosis was constructed by direct wire injury (DWI). Immunoblotting, immunofluorescence staining, and flow cytometry were used to investigate the roles of sirtuin 7 (Sirt7) and nuclear factor erythroid 2-related factor 2 (Nrf2) in hesperetin-mediated protective effects in VICs. RESULTS: Hesperetin supplementation protected the mice from wire-injury-induced aortic valve stenosis; in vitro, hesperetin inhibited the lipopolysaccharide (LPS)-induced activation of NF-κB inflammatory cytokine secretion and osteogenic factors expression, reduced ROS production and apoptosis, and abrogated LPS-mediated injury to the mitochondrial membrane potential and the decline in the antioxidant levels in VICs. These benefits of hesperetin may have been obtained by activating Nrf2-ARE signaling, which corrected the dysfunctional mitochondria. Furthermore, we found that hesperetin could directly bind to Sirt7 and that the silencing of Sirt7 decreased the effects of hesperetin in VICs and potently abolished the ability of hesperetin to increase Nrf2 transcriptional activation. CONCLUSIONS: Our work demonstrates that hesperetin plays protective roles in the aortic valve through the Sirt7-Nrf2-ARE axis; thus, hesperetin might be a potential dietary supplement that could prevent the development of CAVD.

The α7 nicotinic acetylcholine receptor agonist PNU-282987 ameliorates sepsis-induced acute kidney injury through CD4+CD25+ regulatory T cells in rats.

The ameliorative effects of α7 nicotinic acetylcholine receptor (α7nAChR) agonists have been demonstrated in acute kidney injury (AKI) caused by multiple stimulations. However, the ameliorative effect of α7nAChR on sepsis-induced acute kidney injury (SAKI) in the cecal ligation and puncture (CLP) model is unclear. Previous studies have demonstrated that α7nAChR is highly expressed on the surface of CD4+CD25+ regulatory T cells (Tregs). However, the role of Tregs in SAKI is unclear. We hypothesized that Tregs might play a role in the ameliorative effect of α7nAChR on SAKI. Hence, in this study, we determined the effects of PNU-282987 (a selective α7nAchR agonist) on SAKI and evaluated whether PNU-282987 would attenuate SAKI via regulating Tregs. Our study showed that immediate administration of PNU-282987 after CLP surgery in rats improved renal function, reduced levels of systemic inflammatory factors (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), etc.), inflammatory cell infiltration and tubular apoptosis in renal tissues, and increased forkhead/winged helix transcription factor p3 (Foxp3) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expression indicating activated Tregs. Moreover, in in vitro experiments, isolated Tregs co-cultured with PNU-282987 also displayed enhanced expression of CTLA-4 and Foxp3. Furthermore, Tregs were co-cultured with PNU-282987 for 24 hours and then reinfused into rats through the tail vein immediately after CLP surgery, and a significant renal protective effect was observed 24 hours postoperatively. These results demonstrate that PNU-282987 exerts its renal protective effects on SAKI through activation of Tregs.

Development of a Multivariable Prediction Model for Citrate Accumulation in Liver Transplant Patients Undergoing Continuous Renal Replacement Therapy with Regional Citrate Anticoagulation.

INTRODUCTION: Patients with impaired citrate metabolism may experience citrate accumulation (CA), which causes life-threatening metabolic acidosis and hypocalcemia. CA poses a challenge for clinicians when deciding on the use of regional citrate anticoagulation (RCA) for patients with liver dysfunction. This study aimed to develop a prediction model integrating multiple clinical variables to assess the risk of CA in liver transplant patients. METHODS: This single-center prospective cohort study included postoperative liver transplant patients who underwent continuous renal replacement therapy (CRRT) with RCA. The study end point was CA. A prediction model was developed using a generalized linear mixed-effect model based on the Akaike information criterion. The predictive values were assessed using the receiver operating characteristic curve and bootstrap resampling (times = 500) to estimate the area under the curve (AUC) and the corresponding 95% confidence interval (CI). A nomogram was used to visualize the model. RESULTS: This study included 32 patients who underwent 133 CRRT sessions with RCA. CA occurred in 46 CRRT sessions. The model included lactate, norepinephrine >0.1 µg/kg/min, alanine aminotransferase, total bilirubin, and standard bicarbonate, which were tested before starting each CRRT session and body mass index, diabetes mellitus, and chronic kidney disease as predictors. The AUC of the model was 0.867 (95% CI 0.786-0.921), which was significantly higher than that of the single predictor (p < 0.05). A nomogram visualized the prediction model. CONCLUSIONS: The prediction model integrating multiple clinical variables showed a good predictive value for CA. A nomogram visualized the model for easy application in clinical practice.

Antagonism of Cerebral High Mobility Group Box 1 Ameliorates Dendritic Cell Dysfunction in Sepsis.

Sepsis has emerged as a global health issue, and accounts for millions of deaths in intensive care units. Dysregulation of the immune response reportedly contributes to the pathogenesis and progression of this lethal condition, which involves both the dysfunction of immune cells and incompetent immunomodulatory mechanisms. High mobility group box 1 (HMGB1) is known as a later inflammatory mediator and is critically involved in the severity and prognosis of sepsis by inducing intractable inflammation and dysfunction of various immune cells. In the present study, we found that intracerebroventricular (ICV) injection of Box A, a specific antagonist of HMGB1, restored the dysregulated response of splenic dendritic cells (DCs) in septic mice by enhancing the expression of surface molecules, including CD80, CD86, and MHC-II, as well as improving DC priming of T lymphocytes. Cerebral HMGB1 was also confirmed to have potent inhibitory effects on DC functions when administrated by ICV injection in normal mice. The brain cholinergic system was found to mediate the immunomodulatory effects of central HMGB1, as it exhibited enhanced activity with persistent HMGB1 exposure. Furthermore, the inhibitory effects of cerebral HMGB1 on the response of peripheral DCs were also blocked by α7nAchR gene knockout. These findings provide novel insight into the relationship between cerebral HMGB1 and splenic DC dysfunction during sepsis, which is, at least in part, dependent on cholinergic system activity.

Electronic Coordination Effect of the Regulator on Perovskite Crystal Growth and Its High-Performance Solar Cells.

The rapid growth of perovskite crystals leads to excessive grain boundaries and surface defects, which have a negative effect on the performance of solar cells (PSCs). Passivating defects by controlling the crystal growth rate becomes a crucial research hotspot for preparing high-crystallinity perovskite films. In this work, phenylacetonitrile (PA) and 2-naphthylacetonitrile (2-NA) serving as crystal growth regulators are introduced into the perovskite precursor. The coordination effect of lone-pair electrons (n-electrons) and π-electrons in the regulator molecule with Pb2+ on the nucleation and growth of FA0.80MA0.15Cs0.05Pb(I0.85Br0.15)3 perovskite crystal along with the passivation of surface defects and grain boundaries are systematically investigated. The n-electrons of N atom form a coordination bond with Pb2+, and the π-electrons in the aromatic ring generate a cation-π interaction with Pb2+. This combined effect efficiently delays the crystallization rate of the perovskite crystal and then promotes the grain growth and reduces the grain boundaries, which is favorable for the dissociation of more excitons to carriers. The PA-optimized PSCs shows an increase of power conversion efficiency (PCE) from 18.01 to 21.09%, with an unencapsulated device retaining 91.2% of its initial efficiency for 60 days in 40 ± 5% relative humidity under dark conditions.

H-bonding effect of oxyanions enhanced photocatalytic degradation of sulfonamides by g-C3N4 in aqueous solution.

In this study, the effect of oxyanions on the photodegradation of sulfonamides by graphitic carbon nitride (g-C3N4) was investigated. The results showed that the presence of disilicate (DS) could substantially improve the photodegradation of sulfamethazine (SMZ) in g-C3N4 aqueous suspension. The primary mechanism for the enhancing effect of DS was hydrogen bonding (H-bonding) interaction. The hydroxyl groups (OH) and bridging oxygen (SiOSi) of DS can form H-bonds with the amine groups of g-C3N4 particles and sulfonamides, therefore soluble DS can act as a bridge to enhance the transfer and adsorption of SMZ onto the surface of g-C3N4 particles. The presence of DS did not change the mechanism of photodegradation, but there was an optimal concentration for DS to achieve the strongest enhancing effect. H-bonding effect was also found for other oxyanions derived from weak acids, such as silicate, dihydrogen phosphate and borate ions, because the partial ionization of these oxyanions allowed the existence of hydroxyl groups to form H-bonds. The present study not only deepens our understanding of the interface process of the photodegradation of sulfonamides in g-C3N4 aqueous suspension, but also provides a potential method to enhance the photocatalytic degradation of antibiotics in wastewater streams.

Role of the Ca2+-Calcineurin-Nuclear Factor of Activated T cell Pathway in Mitofusin-2-Mediated Immune Function of Jurkat Cells.

BACKGROUND: Mitofusin-2 (MFN2), a well-known mitochondrial fusion protein, has been shown to participate in innate immunity, but its role in mediating adaptive immunity remains poorly characterized. In this study, we explored the potential role of MFN2 in mediating the immune function of T lymphocytes. METHODS: We manipulated MFN2 gene expression in Jurkat cells via lentiviral transduction of MFN2 small interfering RNA (siRNA) or full-length MFN2. After transduction, the immune response and its underlying mechanism were determined in Jurkat cells. One-way analysis of variance and Student's t-test were performed to determine the statistical significance between the groups. RESULTS: Overexpression of MFN2 enhanced the immune response of T lymphocytes by upregulating Ca2+ (359.280 ± 10.130 vs. 266.940 ± 10.170, P = 0.000), calcineurin (0.513 ± 0.014 vs. 0.403 ± 0.020 nmol/L, P = 0.024), and nuclear factor of activated T cells (NFATs) activation (1.040 ± 0.086 vs. 0.700 ± 0.115, P = 0.005), whereas depletion of MFN2 impaired the immune function of T lymphocytes by downregulating Ca2+ (141.140 ± 14.670 vs. 267.060 ± 9.230, P = 0.000), calcineurin (0.054 ± 0.030 nmol/L vs. 0.404 ± 0.063 nmol/L, P = 0.000), and NFAT activation (0.500 ± 0.025 vs. 0.720 ± 0.061, P = 0.012). Furthermore, upregulated calcineurin partially reversed the negative effects of MFN2 siRNA on T cell-mediated immunity evidenced by elevations in T cell proliferation (1.120 ± 0.048 vs. 0.580 ± 0.078, P = 0.040), interleukin-2 (IL-2) production (473.300 ± 24.100 vs. 175.330 ± 12.900 pg/ml, P = 0.000), and the interferon-γ/IL-4 ratio (3.080 ± 0.156 vs. 0.953 ± 0.093, P = 0.000). Meanwhile, calcineurin activity inhibitor depleted the positive effects of overexpressed MFN2 on T cells function. CONCLUSIONS: Our findings suggest that MFN2 may regulate T cell immune functions primarily through the Ca2+-calcineurin-NFAT pathway. MFN2 may represent a potential therapeutic target for T cell immune dysfunction-related diseases.

Early antagonism of cerebral high mobility group box-1 protein is benefit for sepsis induced brain injury.

Sepsis induced brain injury acts as an acute complication and accounts for deterioration and high mortality rate of septic condition. HMGB1 is a late inflammatory mediator that plays a critical role in brain dysfunction and diseases. However, the role of HMGB1 in sepsis induced brain dysfunction remains intricate. The current study investigated the effect of HMGB1 on brain injury in septic mice model with intracerebroventricular injection of BoxA (a specific antagonist of HMGB1). The expression of HMGB1, morphological changes of brain tissues, apoptosis of brain cells, and alteration of behavior were determined. The expressions of HMGB1 in cortex, hippocampus, and striatum were significantly enhanced in the sepsis group when compared with the sham group. In septic conditions, brain tissues showed significant abnormalities in tissue structure, and increased apoptosis of brain cells which was caspase-3 dependent. Septic mice showed suppression of locomotor activity and impairment of memory and learning. Neutralizing brain HMGB1 significantly improved brain injury and apoptosis of brain cells, and further ameliorated disturbed locomotor activities and damaged memory and learning. However, no significant improvement of survival rate was seen after inhibiting central HMGB1. These results reveal that HMGB1 is a potential target for ameliorating sepsis induced brain injury with early antagonizing.

The Protective Effect of Alpha 7 Nicotinic Acetylcholine Receptor Activation on Critical Illness and Its Mechanism.

Critical illnesses and injuries are recognized as major threats to human health, and they are usually accompanied by uncontrolled inflammation and dysfunction of immune response. The alpha 7 nicotinic acetylcholine receptor (α7nAchR), which is a primary receptor of cholinergic anti-inflammatory pathway (CAP), exhibits great benefits for critical ill conditions. It is composed of 5 identical α7 subunits that form a central pore with high permeability for calcium. This putative structure is closely associated with its functional states. Activated α7nAChR exhibits extensive anti-inflammatory and immune modulatory reactions, including lowered pro-inflammatory cytokines levels, decreased expressions of chemokines as well as adhesion molecules, and altered differentiation and activation of immune cells, which are important in maintaining immune homeostasis. Well understanding of the effects and mechanisms of α7nAChR will be of great value in exploring effective targets for treating critical diseases.

[Effects of ulinastatin on immune function of patients with severe burn injury].

OBJECTIVE: To primarily evaluate the effects of ulinastatin on immune function of patients with severe burn injury. METHODS: Forty patients with severe burn admitted to our ward from March 2013 to October 2015, conforming to the study criteria, were divided into conventional treatment group (CT, n=20) and ulinastatin treatment group (UT, n=20) according to the random number table and patient's consent. After admission, patients in group CT received antishock treatment, antibiotic treatment, debridement, skin grafting, and nutrition support, etc. On the basis of the above-mentioned treatment, patients in group UT received intravenous drip of ulinastatin from first day after admission twice a day, with a dosage of 8×10(5) U every time, for 7 days in addition. Peripheral venous blood samples were collected from patients in groups CT and UT on post treatment day (PTD) 1, 3, 5 and 7, respectively. Twenty healthy volunteer were selected as health control group (HC), and peripheral venous blood samples were collected on the first day of the study. Percentage of CD4(+) CD25(+) regulatory T lymphocytes (Tregs) was determined by flow cytometer. The proliferative activity of T lymphocytes was detected by microplate reader (denoted as absorbance value). Content of interleukin 2 (IL-2) in culture supernatant of T lymphocytes, and content of IL-4 and γ interferon (IFN-γ) in serum were detected by enzyme-linked immunosorbent assay. Expression of human leukocyte antigen-DR (HLA-DR) on CD14(+) monocytes was determined by flow cytometer. Data were processed with analysis of variance for repeated measurement, chi-square test, and LSD-t test. RESULTS: (1) Compared with that of volunteer in group HC, the percentage of CD4(+) CD25(+) Tregs of patients in group CT was significantly increased from PTD 1 to 7 (with t values from 13.303 to 26.043, P values below 0.01). Compared with that in group CT, the percentage of CD4(+) CD25(+) Tregs of patients in group UT was significantly decreased on PTD 5 and 7 (with t values respectively 8.317 and 15.071, P values below 0.01). (2) The proliferative activity of T lymphocytes of patients in group CT on PTD 1, 3, 5, and 7 was respectively 0.71±0.11, 0.61±0.15, 0.54±0.12, and 0.67±0.17, which was significantly lower than that in group HC (1.21±0.22, with t values from 8.686 to 11.957, P values below 0.01). The proliferative activity of T lymphocytes of patients in group UT on PTD 3, 5, and 7 were respectively 0.81±0.11, 0.85±0.14, and 1.08±0.13, which was significantly higher than that in group CT (with t values from 4.808 to 8.568, P values below 0.01). (3) Compared with those of volunteer in group HC, content of IL-2 in culture supernatant of T lymphocytes of patients in group CT was significantly decreased from PTD 1 to 7 (with t values from 8.073 to 9.288, P values below 0.01), content of IL-4 in serum of patients in group CT was significantly increased from PTD 1 to 7 (with t values from 18.926 to 41.451, P values below 0.01), and content of IFN-γ in serum of patients in group CT was significantly decreased from PTD 1 to 7 (with t values from 4.543 to 27.659, P values below 0.01). Compared with those in group CT, content of IL-2 in culture supernatant of T lymphocytes of patients in group UT was significantly increased from PTD 3 to 7 (with t values from 6.507 to 8.869, P values below 0.01), content of IL-4 in serum of patients in group UT was significantly decreased from PTD 3 to 7 (with t values from 6.922 to 8.843, P values below 0.01), and content of IFN-γ in serum of patients in group UT was significantly increased on PTD 5 and 7 (with t values respectively 5.369 and 13.521, P values below 0.01). (4) The percentages of CD14(+) monocytes with positive expression of HLA-DR of patients in group CT on PTD 1, 3, 5, and 7 were respectively (28±6)%, (25±7)%, (25±7)%, and (39±10)%, which were significantly lower than the percentage of volunteer in group HC [(87±8)%, with t values from 16.323 to 25.645, P values below 0.01]. The percentages of CD14(+) monocytes with positive expression of HLA-DR of patients in group UT on PTD 3, 5, and 7 were respectively (40±6)%, (42±9)%, and (49±10)%, which were significantly higher than those in group CT (with t values from 3.071 to 7.324, P values below 0.01). CONCLUSIONS: On the basis of CT, additional ulinastatin intervention can decrease CD4(+) CD25(+) Tregs percentage, improve the immune function of T lymphocytes and T helper cells, and increase expression of HLA-DR on CD14(+) monocytes of patients with severe burn injury, thus improve the immune function of patients.

[Effects of ulinastatin on immune function of spleen in severely burned rats and its mechanism].

OBJECTIVE: To observe the effects of ulinastatin on immune function of splenic CD4(+) T lymphocytes and CD4(+) CD25(+) regulatory T lymphocytes (Tregs) and content of high mobility group box 1 (HMGB1) in peripheral blood of severely burned rats, and to analyze the possible mechanisms. METHODS: Ninety-six male SD rats were divided into sham injury group, burn group, and ulinastatin group according to the random number table, with 32 rats in each group. Rats in sham injury group were sham injured on the back by immersing in 37 ℃ warm water for 12 s. Rats in burn group and ulinastatin group were inflicted with 30% total body surface area full-thickness scald (hereinafter referred to as burn) on the back by immersing in 94 ℃ hot water for 12 s. Immediately after injury, rats in each group were intraperitoneally injected with saline (40 mL/kg), meanwhile rats in ulinastatin group were intraperitoneally injected with ulinastatin (4×10(4) U/kg), once per 12 h, till post injury hour 72. Eight rats of each group were respectively selected on post injury day (PID) 1, 3, 5, and 7 to collect abdominal aortic blood samples. Serum content of HMGB1 was detected by enzyme-linked immunosorbent assay (ELISA). And then, rats of the 3 groups were sacrificed immediately to collect spleens and separate CD4(+) CD25(+) Tregs and CD4(+) T lymphocytes. Flow cytometer was used to detect positive expression rates of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and forkhead-winged helix transcription factor p3 (Foxp3) in CD4(+) CD25(+) Tregs. Content of IL-10 in culture supernatant of CD4(+) CD25(+) Tregs, and content of interleukin 2 (IL-2), IL-4, and γ interferon (IFN-γ) in culture supernatant of CD4(+) T lymphocytes was detected by ELISA. The proliferative activity of CD4(+) T lymphocytes was determined by microplate reader. The sample number of above-mentioned experiments was 8 at each time point in each group. Data were processed with analysis of variance of factorial design and LSD test. RESULTS: (1) Compared with that in sham injury group, serum content of HMGB1 of rats in burn group was significantly increased from PID 1 to 7 (with P values below 0.01). Compared with that in burn group, serum content of HMGB1 of rats in ulinastatin group was significantly decreased from PID 1 to 7 (with P values below 0.01). (2) Compared with those in sham injury group, the positive expression rates of CTLA-4 and Foxp3 in CD4(+) CD25(+) Tregs and content of IL-10 in culture supernatant of CD4(+) CD25(+) Tregs of rats in burn group were significantly increased from PID 1 to 7 (with P values below 0.01), peaking on PID 3 [(65±10)%, (76±10)%, and (28.2±4.4) pg/mL respectively]. These 3 indexes of rats in sham injury group on PID 3 were (45±7)%, (46±7)%, and (11.2±2.3) pg/mL respectively. Compared with those in burn group, the positive expression rates of CTLA-4 and Foxp3 in CD4(+) CD25(+) Tregs and content of IL-10 in culture supernatant of CD4(+) CD25(+) Tregs of rats in ulinastatin group were significantly decreased from PID 1 to 7 (P<0.05 or P<0.01), reaching the nadir on PID 7 [(43±6)%], PID 1 [(50±8)%], and PID 7 [(12.4±3.4) pg/mL] respectively. These 3 indexes of rats in burn group on PID 7, 1, and 7 were (58±8)%, (71±9)%, and (19.7±2.8) pg/mL respectively. (3) Compared with those in sham injury group, the content of IL-2 and IFN-γ in culture supernatant of CD4(+) T lymphocytes of rats was significantly decreased, while the content of IL-4 in culture supernatant of CD4(+) T lymphocytes of rats was significantly increased in burn group from PID 1 to 7, with P values below 0.01. Compared with that in burn group, the content of IL-2 and IFN-γ in culture supernatant of CD4(+) T lymphocytes of rats was significantly increased, while the content of IL-4 in culture supernatant of CD4(+) T lymphocytes of rats was significantly decreased in ulinastatin group from PID 1 to 7, P<0.05 or P<0.01. (4) Compared with that in sham injury group, the proliferative activity of CD4(+) T lymphocytes of rats in burn group was significantly decreased from PID 1 to 7 (with P values below 0.01). Compared with that in burn group, the proliferative activity of CD4(+) T lymphocytes of rats in ulinastatin group was significantly increased from PID 1 to 7 (with P values below 0.01). CONCLUSIONS: Ulinastatin can weaken the immunosuppressive function mediated by splenic CD4(+) CD25(+) Tregs in severely burned rats, and improve proliferative function and secretory function of splenic CD4(+) T lymphocytes, which may be attributed to the inhibiting effect of ulinastatin on the release of HMGB1 in large amount.

Effects of CD14 and TLR4 on LPS-mediated normal human skin fibroblast proliferation.

BACKGROUND: This study was designed to elucidate the effects of CD14 and TLR4 on the proliferation of LPS-mediated normal human skin fibroblasts and to gain new insights into the mechanisms underlying LPS-induced scar formation. METHODS: Cell morphology and density were observed using an inverted microscope. Proliferation curves were described by MTT. The number of proliferating cells was counted by staining the cells with trypan blue. Cells were stained with propidium iodide (PI) and the phase of cell generation cycle was determined by flow cytometry. RESULTS: The growth rate detected in groups B, C, D was slower compared to group A after 48 h. All proliferation curves were approximately S shaped and the peak was seen on days 6, followed by a sharp decline on days 7. The proliferation rate of groups B, C, D was significantly slower than group A. After the staining, we found a significantly smaller number of proliferating cells in groups B, C, D as compared to group A. Flow cytometry revealed that the ratio of proliferating cells at S phase was lower in the groups B, C, D as compared to group A. CONCLUSIONS: Both separate and combined use of anti-CD14 and anti-TLR4 enable a significant decline in the rate and capacity of proliferation, with the latter pretreatment resulting in the sharpest reduction. Therefore, it seems likely that anti-CD14 along with anti-TLR4 is significantly engaged in the signaling mechanisms of LPS-mediated fibroblast proliferation.

Role of CD14 and TLR4 in type I, type III collagen expression, synthesis and secretion in LPS-induced normal human skin fibroblasts.

OBJECTIVES: The primary aim of this study was to investigate the role of CD14 and TLR4 in type I, type III collagen expression, synthesis and secretion in LPS-induced normal human skin fibroblasts. The secondary aim was to provide theoretical basis for the molecular mechanisms of scar formation induced by LPS. METHODS: The normal skin fibroblasts cultured in vitro were randomly divided into four groups: 0.1 µg/mL LPS reference group, CD14 pretreatment + LPS, TLR4 pretreatment + LPS, CD14 and TLR4 pretreatment + LPS. The collagen DNA synthesis was assessed by (3)H-proline incorporation method. Real-time Quantitative PCR was used to detect type I, type III collagen mRNA expression. RESULTS: Similar results were revealed for mRNA expression levels. The immunofluorescence staining suggested that type I and type III collagen were expressed in all investigated groups and that the expression was differentially downregulated in groups B, C, D. ELISA demonstrated markedly decreased levels in secreting type I, type III collagens and hydroxyproline in groups B, C, D (P<0.05), and the lowest level was detected in group D (P<0.01). CONCLUSION: Pretreatment with CD14 or TLR4 alone or their combination can significantly reduce the levels of type I and type III collagen expression, synthesis and secretion, with the most notable reduction detected in case of CD14 and TLR4 combined. We could thus conclude that both CD14 and TLR4 are involved in type I and type III collagen expression, synthesis and secretion in LPS-induced skin fibroblasts.

Association of CD14 and TLR4 with LPS-stimulated human normal skin fibroblasts in immunophenotype changes and secretion of TGF-ß1 and IFN-γ.

OBJECTIVES: We attempted to explore the association of CD14 and TLR4 with LPS-stimulated human normal skin fibroblasts in immunophenotype changes and secretion of TGF-ß1 and IFN-γ, and to expand the current knowledge of the mechanisms that underlie LPS-induced scar formation. METHODS: We randomized the human normal skin fibroblasts cultured in vitro into four groups. The expression profile of immune phenotypes was determined by immunohistochemical staining. Ultrastructure of cells was observed by use of transmission electron microscopy. Secretion status of TGF-ß1 and IFN-γ was inspected using ELISA assay. RESULTS: Compared with group A, the expressions of α-SMA and α1 (I) procollagen in groups B, C, D were lower, and it in group D were the lowest in all groups. The cells in group A were diversification under the electron microscope, and the ratio of the nuclear to plasma of the fibroblasts was large, with unregular nuclear membrane, more Golgi apparatus, rough endoplasmic reticulum, and microfilament and canaliculus appeared. The ultrastructure of the fibroblasts in group B, C, D was spindle and the nuclear was large, with regular nuclear membrane, more Golgi apparatus, rough endoplasmic reticulum. ELISA assay indicated that the secretion of TGF-ß1 markedly lowered in groups B, C, D in comparison to group A, with the most marked decline observed in group D. Interestingly, we found significantly increased IFN-γ secretion in groups B, C, D (P < 0.05), with the latter group showing the most notable increase (P < 0.01). CONCLUSION: These data suggest that both combined and isolated use of CD14 and TLR4 significantly reduce α-SMA expression levels, the number of α1 (I) pro-collagen positive cells, and TGF-ß secretion, while substantially increased IFN-γ secretion. The reduction and increase are especially notable when pretreating with CD14 and TLR4 combined. Here we thus draw a conclusion that both CD14 and TLR4 are associated with the immunophenotype changes and secretion of TGF-ß1 and IFN-γ in LPS-stimulated human normal skin fibroblasts.

Burn injury induces gelsolin expression and cleavage in the brain of mice.

Gelsolin is an actin filament-severing and capping protein, affecting cellular motility, adhesiveness and apoptosis. Whether it is expressed in the brain of burned mice has not yet been characterized. Mice were subjected to a 15% total body surface area scald injury. Neuropathology was examined by hematoxylin and eosin staining. Cerebral gelsolin mRNA, distribution and cleavage were demonstrated by quantitative polymerase chain reaction (QPCR), immunohistochemistry and Western blot, respectively. Cysteinyl aspartate-specific protease (caspase)-3-positive cells and activity were also measured. Burn injury could induce pathological alterations in the brain including leukocyte infiltration, necrosis, microabscess and gliosis. Compared with sham-injured mice, gelsolin mRNA was up-regulated at 8h post-burn (pb) in a transient manner in the cortex and striatum of burned mice, while it remained at higher levels in the hippocampus up to 72 hpb. Of interest, gelsolin was further cleaved into 42 and 48 kDa (kilo Dalton) fragments as illustrated in the hippocampus at 24 hpb, and was widely expressed in the brain by activated monocyte/macrophages, astrocytes and damaged neurons. In the meantime, caspase-3-positive cells were noted in the striatum of burned mice and its activity peaked at 24 hpb. To clarify inflammation-induced gelsolin expression and cleavage in the brain, rat pheochromocytoma cells were exposed to lipopolysaccharide to show increased gelsolin expression and caspase-3-dependent cleavage. The results suggest that burn-induced cerebral gelsolin expression would be involved in the activation of both the monocytes and astroglial cells, thereby playing a crucial role in the subsequent inflammation-induced neural apoptosis following burn injury.