Suppression of interleukin-6-induced C-reactive protein expression by FXR agonists

C-reactive protein (CRP), a human acute-phase protein, is a risk factor for future cardiovascular events and exerts direct pro-inflammatory and pro-atherogenic properties. The farnesoid X receptor (FXR), a member of the nuclear hormone receptor superfamily, plays an essential role in the regulation of enterohepatic circulation and lipid homeostasis. In this study, we report that two synthetic FXR agonists, WAY-362450 and GW4064, suppressed interleukin-6-induced CRP expression in human Hep3B hepatoma cells. Knockdown of FXR by short interfering RNA attenuated the inhibitory effect of the FXR agonists and also increased the ability of interleukin-6 to induce CRP production. Furthermore, treatment of wild type C57BL/6 mice with the FXR agonist, WAY-362450, attenuated lipopolysaccharide-induced serum amyloid P component and serum amyloid A3 mRNA levels in the liver, whereas no effect was observed in FXR knockout mice. These data provide new evidence for direct anti-inflammatory properties of FXR.     

Human SAP18 mediates assembly of a splicing regulatory multiprotein complex via its ubiquitin-like fold

RNPS1, Acinus, and SAP18 form the apoptosis- and splicing-associated protein (ASAP) complex, which is also part of the exon junction complex. Whereas RNPS1 was originally identified as a general activator of mRNA processing, all three proteins have been found within functional spliceosomes. Both RNPS1 and Acinus contain typical motifs of splicing regulatory proteins including arginine/serine-rich domains. Due to the absence of such structural features, however, a function of SAP18 in splicing regulation is completely unknown. Here we have investigated splicing regulatory activities of the ASAP components. Whereas a full-length Acinus isoform displayed only limited splicing regulatory activity, both RNPS1 and, surprisingly, SAP18 strongly modulated splicing regulation. Detailed mutational analysis and three-dimensional modeling data revealed that the ubiquitin-like fold of SAP18 was required for efficient splicing regulatory activity. Coimmunoprecipitation and immunofluorescence experiments demonstrated that SAP18 assembles a nuclear speckle-localized splicing regulatory multiprotein complex including RNPS1 and Acinus via its ubiquitin-like fold. Our results therefore suggest a novel function of SAP18 in splicing regulation.     

不同营养治疗途径对重症急性胰腺炎大鼠血浆氨基酸谱和电解质的影响

目的比较不同配方肠内营养(EN)和肠外营养(PN)制剂对重症急性胰腺炎(SAP)大鼠血浆氨基酸谱和电解质水平的影响。方法建立大鼠SAP模型,根据SAP营养代谢配制专用EN配方(EN-S)和含益生元(PRE)的EN配方(RPE-EN)。40只大鼠随机分为正常对照组(A组)、SAP+EN-S组(B组)、SAP+PRE-EN组(C组)、SAP+商品EN组(D组)和SAP+PN组(E组),营养治疗持续7 d,检测血浆氨基酸谱和电解质水平。结果B~E组主要氨基酸和总氨基酸水平显著低于A组(P<0.05),D组天门冬氨酸、蛋氨酸和赖氨酸水平显著低于B组(P<0.05)和C组,而谷氨酸、精氨酸、丙氨酸和苯丙氨酸显著低于C组(P<0.05),低于B组但无显著性差异;B~E组血清铁显著低于A组(P<0.05),D组的血清铁显著低于C组(P<0.05),除C组外,其余各组的血浆钠显著低于A组。结论EN-S配方在提高某些氨基酸水平上作用优于商品EN;含PRE微生态营养制剂具有改善蛋白质代谢和电解质平衡的作用;短期应用EN和PN对SAP动物蛋白质代谢和电解质平衡作用无显著性差异。     

Constitutive expression of the SAP1 gene from willow (Salix discolor) causes early flowering in Arabidopsis thaliana

SAP1-1 and SAP1-2 were isolated from the male reproductive buds of willow (Salix discolor, clone S365). SAP1-1 differs from SAP1-2 based on a few nucleotide substitutions, but the sizes of their full-length cDNAs are identical. The deduced amino acid sequences of SAP1-1 and SAP1-2 were 98% similar and contain the same C-terminal amino acid motif “GYGA” like that of PTAP1-2 from Populus trichocarpa. The expression patterns of SAP1 in various parts of the male reproductive buds of S. discolor implicate this gene in the formation of the inflorescence meristems, bracts, and floral meristems. To characterize the functions of SAP1, we assessed Arabidopsis thaliana transformed with 35S∷SAP1-1. A total of 52 transgenic T₁ lines were obtained, and a 3:1 segregation ratio was obtained in the T₂ generation of each line. In the T₃ generation, five homozygous transgenic lines were obtained, which were used for further analysis. Screening of transgenic lines was greatly facilitated by the detection of GFP expression starting with germinating seeds. Phenotypes of the homozygous transgenic lines included early flowering, conversion of inflorescence branches to solitary flowers, formation of terminal flowers, and formation of flowers with greater number of petals, stamens, and pistils. Northern analysis showed similar expression levels in all five lines. This study provides the first functional analysis of an APETALA1 (AP1)/SQUAMOSA (SQUA) homolog from a dioecious species and suggests that SAP1 is a homolog of the AP1/SQUA gene.     

Goodpasture antigen-binding protein/ceramide transporter binds to human serum amyloid P-component and is present in brain amyloid plaques

Serum amyloid P component (SAP) is a non-fibrillar glycoprotein belonging to the pentraxin family of the innate immune system. SAP is present in plasma, basement membranes, and amyloid deposits. This study demonstrates, for the first time, that the Goodpasture antigen-binding protein (GPBP) binds to human SAP. GPBP is a nonconventional Ser/Thr kinase for basement membrane type IV collagen. Also GPBP is found in plasma and in the extracellular matrix. In the present study, we demonstrate that GPBP specifically binds SAP in its physiological conformations, pentamers and decamers. The START domain in GPBP is important for this interaction. SAP and GPBP form complexes in blood and partly colocalize in amyloid plaques from Alzheimer disease patients. These data suggest the existence of complexes of SAP and GPBP under physiological and pathological conditions. These complexes are important for understanding basement membrane, blood physiology, and plaque formation in Alzheimer disease.     

晶胶联合大黄在早期治疗重症急性胰腺炎中的临床意义

目的:研究晶胶联合大黄在早期治疗重症急性胰腺炎中的临床意义.方法:选取2011年1月至2013年1月已被收治的符合标准的病例共174例重症急性胰腺炎患者随机分为晶胶联合组(A组)和晶胶联合大黄组(B组)两组,每组87例,观察不同治疗方案对液体负平衡出现时间(D1),肠道功能恢复时间,病死率及多器官功能障碍综合征(MODS)发生率,红细胞压积(HCT),液体滞留总量,血乳酸,中心静脉血氧饱和度(ScvO2),胃黏膜pH值(pHi)等指标的影响.结果:治疗后B组各项指标的改善均优于A组(P＜0.05).B组治疗后的液体负平衡出现时间(70±16.8)h,液体滞留总量(425.5± 90.5) mL,肠道功能恢复时间(39±9.5)h,MODS发生率为18.4％,病死率为4.6％,HCT(30.2± 9.5)％,ScvO2为(87.4±12.7)％,pHi为(7.9±1.1),血乳酸为(1.4±0.8)mmol/L(所有P＜0.05).结论:在早期治疗重症急性胰腺炎时应用晶胶联合大黄组可缩短负平衡出现时间,加速循环血容量恢复,增加组织血液灌注和供氧,促进肠道功能恢复,维护重要脏器功能,缩短液体复苏的时间,改善该病的预后,有显著的临床意义.     

Certain Strongylocentrotus purpuratus sperm mitochondrial proteins co-purify with low density detergent-insoluble membranes and are PKA or PKC-substrates possibly involved in sperm motility regulation

Background

Sea urchin sperm motility is regulated by Speract, a sperm-activating peptide (SAP) secreted from the outer egg coat. Upon binding to its receptor in the sperm flagellum, Speract induces a series of ionic and metabolic changes in Strongylocentrotus purpuratus spermatozoa that regulate their motility. Among these events, protein phosphorylation is one of the most relevant and evidence indicates that some proteins of the Speract signaling cascade localize in low density detergent-insoluble membranes (LD-DIM).

Methods

LD-DIM-derived proteins from immotile, motile or Speract-stimulated S. purpuratus sperm were resolved in 2-D gels and the PKA and PKC substrates detected with specific antibodies were identified by LC–MS/MS.

Results

Differential PKA and PKC substrate phosphorylation levels among the LD-DIM isolated from sperm in different motility conditions were found and identified by mass spectrometry as: ATP synthase, creatine kinase, NADH dehydrogenase (ubiquinone) flavoprotein 2, succinyl-CoA ligase and the voltage-dependent anion channel 2 (VDAC2), which are mitochondrial proteins, as well as, the cAMP-dependent protein kinase type II regulatory (PKA RII) subunit, Tubulin β chain and Actin Cy I changed their phosphorylation state.

Conclusions

Some mitochondrial proteins regulated by PKA or PKC may influence sea urchin sperm motility.

General significance

The fact that a high percentage (66%) of the PKA or PKC substrates identified in LD-DIM are mitochondrial proteins suggests that the phosphorylation of these proteins modulates sea urchin sperm motility via Speract stimulation by providing sufficient energy to sperm physiology. Those mitochondrial proteins are indeed PKA- or PKC-substrates in the sea urchin spermatozoa.     

2B4+ CD8+ T cells play an inhibitory role against constrained HIV epitopes

Cytotoxic T cells play a critical role in the control of HIV and the progression of infected individuals to AIDS. 2B4 (CD244) is a member of the SLAM family of receptors that regulate lymphocyte development and function. The expression of 2B4 on CD8⁺ T cells was shown to increase during AIDS disease progression. However, the functional role of 2B4⁺ CD8⁺ T cells against HIV infection is not known. Here, we have examined the functional role of 2B4⁺ CD8⁺ T cells during and after stimulation with HLA B14 or B27 restricted HIV epitopes. Interestingly, IFN-γ secretion and cytotoxic activity of 2B4⁺ CD8⁺ T cells stimulated with HIV peptides were significantly decreased when compared to influenza peptide stimulated 2B4⁺ CD8⁺ T cells. The expression of the signaling adaptor molecule SAP was downregulated in 2B4⁺ CD8⁺ T cells upon HIV peptide stimulation. These results suggest that 2B4⁺ CD8⁺ T cells play an inhibitory role against constrained HIV epitopes underlying the inability to control the virus during disease progression.     

Heterocomplexes of mannose-binding lectin and the pentraxins PTX3 or serum amyloid P component trigger cross-activation of the complement system

The long pentraxin 3 (PTX3), serum amyloid P component (SAP), and C-reactive protein belong to the pentraxin family of pattern recognition molecules involved in tissue homeostasis and innate immunity. They interact with C1q from the classical complement pathway. Whether this also occurs via the analogous mannose-binding lectin (MBL) from the lectin complement pathway is unknown. Thus, we investigated the possible interaction between MBL and the pentraxins. We report that MBL bound PTX3 and SAP partly via its collagen-like domain but not C-reactive protein. MBL-PTX3 complex formation resulted in recruitment of C1q, but this was not seen for the MBL-SAP complex. However, both MBL-PTX3 and MBL-SAP complexes enhanced C4 and C3 deposition and opsonophagocytosis of Candida albicans by polymorphonuclear leukocytes. Interaction between MBL and PTX3 led to communication between the lectin and classical complement pathways via recruitment of C1q, whereas SAP-enhanced complement activation occurs via a hitherto unknown mechanism. Taken together, MBL-pentraxin heterocomplexes trigger cross-activation of the complement system.     

甘蔗锌指蛋白基因ShSAP1的克隆与表达模式

植物中具有A20/AN1锌指结构域的蛋白与逆境应答密切相关,在甘蔗热带种Saccharum officinarum拔地拉Badila中克隆到一个具有A20/AN1锌指结构域的锌指蛋白基因ShSAP1。为研究ShSAP1的基因结构和表达特性,采用PCR和Southern blotting分析了ShSAP1的基因组结构,通过半定量RT-PCR对ShSAP1在甘蔗不同部位、不同胁迫和不同激素处理下的表达模式进行了分析。结果表明,ShSAP1的5'UTR区有两段内含子,大小分别为202 bp和1 052 bp,在