Differential regulation of proteasome activity in the nucleus and the synaptic terminals

Proteasome is a multi-subunit proteolytic complex that degrades proteins covalently linked to multiple molecules of ubiquitin. Earlier studies showed a role for the ubiquitin-proteasome pathway in several models of long-term memory and other forms of synaptic plasticity. In Aplysia, the ubiquitin-proteasome pathway has been shown to contribute to the induction of long-term facilitation. In other model systems, ubiquitin-proteasome-mediated proteolysis has also been shown to play a role in synapse development. Previous studies of synaptic plasticity focused on changes in components or the substrates of the ubiquitin-proteasome pathway in whole neurons. Modification of specific synapses would require precise spatial and temporal regulation of the components of the ubiquitin-proteasome pathway within the subcellular compartments of neurons during learning. As a first step towards testing the idea of local regulation of the ubiquitin-proteasome pathway in neurons, we investigated proteasome activity in nuclear and synaptosomal fractions. Here we show that proteasome activity in the synaptic terminals is higher compared to the activity in the nucleus in the Aplysia nervous system as well as in the mouse brain. Furthermore, the proteasome activity in the two neuronal compartments is differentially modulated by protein kinases. Differential regulation of proteasome activity in neuronal compartments such as the synaptic terminals is likely to be a key mechanism underlying synapse-specific plasticity.

XBAT31 regulates thermoresponsive hypocotyl growth through mediating degradation of the thermosensor ELF3 in Arabidopsis

Elevated ambient temperature has wide effects on plant growth and development. ELF3, a proposed thermosensor, negatively regulates protein activity of the growth-promoting factor PIF4, and such an inhibitory effect is subjected to attenuation at warm temperature. However, how ELF3 stability is regulated at warm temperature remains enigmatic. Here, we report the identification of XBAT31 as the E3 ligase that mediates ELF3 degradation in response to warm temperature in Arabidopsis XBAT31 interacts with ELF3, ubiquitinates ELF3, and promotes ELF3 degradation via the 26S proteasome. Mutation of XBAT31 results in enhanced accumulation of ELF3 and reduced hypocotyl elongation at warm temperature. In contrast, overexpression of XBAT31 accelerates ELF3 degradation and promotes hypocotyl growth. Furthermore, XBAT31 interacts with the B-box protein BBX18, and the XBAT31-mediated ELF3 degradation is dependent on BBX18 Thus, our findings reveal that XBAT31-mediated destruction of ELF3 represents an additional regulatory layer of complexity in temperature signaling during plant thermomorphogenesis.

Fibronectin fragments mediate matrix metalloproteinase upregulation and cartilage damage through proline rich tyrosine kinase 2, c-src, NF-kappaB and protein kinase Cdelta

OBJECTIVE

Since fibronectin fragments (Fn-fs) enhance cartilage damage through integrins, the objective was to investigate the role of integrin linked kinases, focal adhesion kinase (FAK) and a soluble form of FAK, proline rich tyrosine kinase 2 (Pyk2) and cellular src kinase (c-src) and the transcription factor, nuclear factor kappaB (NF-kappaB) in cartilage damage.

METHODS

Bovine chondrocytes were cultured with various concentrations of three different Fn-fs, an amino-terminal 29 kDa, a gelatin binding 50 kDa and a central 140-kDa Fn-fs, each with progressively weaker cartilage damaging activity, or with native fibronectin (Fn), and lysates probed for activation of the selected kinases. Confocal microscopy was used to visualize intracellular location of activated kinases and NF-kappaB. Various kinase inhibitors were tested for their effects on Fn-f mediated upregulation of matrix metalloproteinase (MMP)-3 and -13 and cartilage proteoglycan (PG) depletion.

RESULTS

The Fn-fs kinetically enhanced phosphorylation of FAK but did not show a clear dose-response effect. The 29-kDa and 50-kDa Fn-fs enhanced phosphorylation of Pyk2, c-src and NF-kappaB to a much greater extent than the 140-kDa Fn-f and native Fn and did so as a function of dose. The 29-kDa Fn-f enhanced the phosphorylation of nuclear Pyk2 as compared with no treatment or native Fn. Inhibitors of Pyk2, c-src, NF-kappaB and protein kinase Cdelta (PKCdelta) decreased MMP upregulation and decreased Fn-f mediated damage to cartilage.

CONCLUSIONS

These studies enhance our knowledge of crucial factors in Fn-f mediated signaling in MMP upregulation and cartilage damage and because of the potential physiologic relevance of Fn-fs, provide a better knowledge of cartilage degeneration in general.

The impact of chromosomal translocation locus and fusion oncogene coding sequence in synovial sarcomagenesis

Synovial sarcomas are aggressive soft-tissue malignancies that express chromosomal translocation-generated fusion genes, SS18-SSX1 or SS18-SSX2 in most cases. Here, we report a mouse sarcoma model expressing SS18-SSX1, complementing our prior model expressing SS18-SSX2. Exome sequencing identified no recurrent secondary mutations in tumors of either genotype. Most of the few mutations identified in single tumors were present in genes that were minimally or not expressed in any of the tumors. Chromosome 6, either entirely or around the fusion gene expression locus, demonstrated a copy number gain in a majority of tumors of both genotypes. Thus, by fusion oncogene coding sequence alone, SS18-SSX1 and SS18-SSX2 can each drive comparable synovial sarcomagenesis, independent from other genetic drivers. SS18-SSX1 and SS18-SSX2 tumor transcriptomes demonstrated very few consistent differences overall. In direct tumorigenesis comparisons, SS18-SSX2 was slightly more sarcomagenic than SS18-SSX1, but equivalent in its generation of biphasic histologic features. Meta-analysis of human synovial sarcoma patient series identified two tumor-gentoype-phenotype correlations that were not modeled by the mice, namely a scarcity of male hosts and biphasic histologic features among SS18-SSX2 tumors. Re-analysis of human SS18-SSX1 and SS18-SSX2 tumor transcriptomes demonstrated very few consistent differences, but highlighted increased native SSX2 expression in SS18-SSX1 tumors. This suggests that the translocated locus may drive genotype-phenotype differences more than the coding sequence of the fusion gene created. Two possible roles for native SSX2 in synovial sarcomagenesis are explored. Thus, even specific partial failures of mouse genetic modeling can be instructive to human tumor biology.

Pancreatic microcirculation in acute pancreatitis

We present a review of the microvascular morphology of the pancreas and microstructure of the pancreatic lobule, and report our experimental results of the investigation of pancreatic microcirculation following acute pancreatitis. Impairment of pancreatic microcirculation in the early phase of acute pancreatitis may play a key role in the progression of this disease. Possible contributory mechanisms include increased vascular permeability, reduced blood flow, leukocyte-endothelial cell interaction and intravascular thrombus formation. Using an in-vivo microscope system and off-line computer analysis, we achieved direct visualization and quantification of changes in microvascular permeability and leukocyte behavior in pancreas with acute pancreatitis. Bradykinin and oxygen radicals have been demonstrated to be involved in the increase of vascular permeability in the early stage of caerulein pancreatitis. Leukocyte adherence to the vessels in the pancreatic microcirculation is a secondary event following permeability changes in acute pancreatitis. Leukocyte infiltration during exacerbation of acute pancreatitis is mediated by leukocyte-endothelial cell interaction via leukocyte integrin CD11b/18.

Visual outcomes of Visian ICL implantation for high myopia in patients with shallow anterior chamber depth

Background

High myopia with shallow anterior chamber depth (ACD less than 2.8 mm) is not rare. This observational study aims to evaluate visual outcomes after implantation of the Visian Implantable Collamer Lens with a central hole (ICL V4c) in these patients.

Methods

A prospective cohort of consecutive 51 eyes of 31 patients (20 to 42 years old) was followed for at least 12 months (average 15.35 ± 4.90 months, rangers from 12 to 25 months). The preoperative ACD was 2.74 ± 0.04 mm (2.65 to 2.79 mm). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), intraocular pressure (IOP), manifest refraction, vault, and endothelial cell density (ECD) were measured during the follow-ups after surgery.

Results

All surgeries were performed safely and no complication was observed during the follow-ups. At the last follow-up, the safety index (postoperative CDVA / preoperative CDVA) was 1.33 ± 0.60 and the efficacy index (postoperative UDVA / preoperative CDVA) was 1.14 ± 0.54. After the surgery, no eye had decreased CDVA and 59% (30 eyes) of the eyes gained at least one line. Forty-seven eyes (92%) were within ±1.0 D and 35 eyes (69%) were within ±0.5 D of the attempted refraction. The mean postoperative vault was 380.00 ± 152.84 μm (90 to 700 μm). The ECD was reduced by 8.38 ± 0.06% as compared to the preoperative value (p < 0.001). No significant change was observed in IOP (p = 0.061) at the last follow-up. Ultrasound Biomicroscopy (UBM) showed none of the eyes had trabecular-iris angle closed.

Conclusions

In this prospective observational study, ICL V4c implantation in patients with high myopia and shallow ACD achieved satisfying and stable visual outcomes. Its long-term safety and stability require further investigation.

Trial registration

This trial was retrospectively registered on 05/08/2018 under the number (ChiCTR1800017594).

Anti-human immunodeficiency virus effects of cationic metalloporphyrin-ellipticine complexes

A series of cationic metalloporphyrin-ellipticine complexes were found to inhibit the cytopathicity of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus in MT-4 cells at concentrations ranging from 1.4 to 17 micrograms/mL, i.e. at a concentration that was 2.5-30-fold below the cytotoxicity threshold. These compounds were also found to inhibit syncytium formation between persistently HIV-1-infected HUT-78 and uninfected Molt/4 cells, to interfere with HIV-1 binding to the cells, and to suppress HIV-1-associated reverse transcriptase activity.

Human immunodeficiency virus-seronegative adults with extrapulmonary tuberculosis have abnormal innate immune responses

Extrapulmonary tuberculosis is presumably a marker of underlying immunodeficiency, but cytokine response pathways in these patients have not been well studied. Cytokine responses of peripheral blood mononuclear cells from human immunodeficiency virus-seronegative adults with prior culture-confirmed extrapulmonary tuberculosis were compared with those of persons with latent Mycobacterium tuberculosis infection. Mitogen-stimulated interferon (IFN)-gamma production, interleukin (IL)-12 production, and IFN-gamma receptor- and IL-12 receptor-mediated cytokine production did not differ between case patients and control patients. However, median resting IL-8 production was significantly lower in case patients than control patients (8051 vs. 19,290 pg/mL; P=.009). In addition, the median tumor necrosis factor (TNF)-alpha response was lower in case patients than control patients after stimulation with lipopolysaccharide (833 vs. 1149 pg/mL; P=.06) and lipopolysaccharide plus IFN-gamma (3301 vs. 4411 pg/mL; P=.04). These abnormalities in resting IL-8 and lipopolysaccharide-induced TNF-alpha production were not associated with IFN-gamma or IL-12 abnormalities and were detected up to several years after cure of disease, suggesting an abnormality in innate immunity.

Dynamic microwave-assisted extraction coupled with salting-out liquid-liquid extraction for determination of steroid hormones in fish tissues

In this work, a simple and fast sample pretreatment method was proposed for determination of steroid hormones in fish tissues by coupling dynamic microwave-assisted extraction with salting-out liquid-liquid extraction. The steroid hormones were successively extracted with acetonitrile and water under the action of microwave energy. Subsequently, the extract was separated into an acetonitrile phase and an aqueous phase with ammonium acetate. The acetonitrile phase containing the target analytes was concentrated and determined by LC-MS/MS. The limits of detection for the steroid hormones were in the range of 0.03-0.15 ng g(-1). This method was successfully applied to analyze seven kinds of fish tissues, and the recoveries of the steroid hormones for the spiked samples were in the range of 75.3 ± 4.9% to 95.4 ± 6.2%. Compared with the traditional method, the proposed method could reduce the consumption of the organic solvent, shorten the sample preparation time, and increase the sample throughput.

Cloning, expression, and characterization of the Escherichia coli K-12 rfaD gene

The rfaD gene encodes ADP-L-glycero-D-mannoheptose-6-epimerase, an enzyme required for the biosynthesis of the lipopolysaccharide precursor ADP-L-glycerol-D-mannoheptose. The precise localization of the rfaD gene on a 1.3-kilobase SspI-HpaI fragment is reported. The rfaD gene and the flanking regions were completely sequenced. The location of the rfaD gene on the physical map of the Escherichia coli chromosome was determined. Primer extension studies were used to define the regulatory region of the rfaD gene. The cloned rfaD gene directed the synthesis of a 37,000-dalton polypeptide in several in vivo and in vitro expression systems. N-terminal analysis of purified ADP-L-glycero-D-mannoheptose-6-epimerase confirmed the first 34-amino-acid sequence deduced from the nucleotide sequence of the rfaD gene coding region. The primary structure of the rfaD protein contains the sequence fingerprint for the ADP-binding beta alpha beta fold at the N terminus.

Continuous determination of total flavonoids in Platycladus orientalis (L.) Franco by dynamic microwave-assisted extraction coupled with on-line derivatization and ultraviolet–visible detection

This paper describes a new method for the determination of total flavonoids in Platycladus orientalis (L.) Franco. The method was based on dynamic microwave-assisted extraction (DMAE) coupled with on-line derivatization and ultraviolet-visible (UV-vis) detection. The influence of the experimental conditions was tested. Maximum extraction yield was achieved using 80% aqueous methanol of extraction solvent; 80 W of microwave output power; 5 min of extraction time; 1.0 mL min(-1) of extraction solvent flow rate. The derivatization reaction between aluminium chloride and flavonoid is one of the most sensitive and selective reactions for total flavonoids determination. The optimized derivatization conditions are as follows: derivatization reagent 1.5% aluminium chloride methanol solution; reaction coil length 100 cm; derivatization reagent flow rate 1.5 mL min(-1). The detection and quantification limits obtained are 0.28 and 0.92 mg g(-1), respectively. The intra-day and inter-day precisions (R.S.D.) obtained are 1.5% and 4.6%, respectively. Mean recovery is 98.5%. This method was successfully applied to the determination of total flavonoids in P. orientalis (L.) Franco and compared with heat reflux extraction. The results showed that the higher extraction yield of total flavonoids was obtained by DMAE with shorter extraction time (5 min) and small quantity of extraction solvent (5 mL).

Interferon alpha treatment of patients with impaired interferon gamma signaling

Patients with deficiency in the interferon gamma receptor (IFN-γR) are unable to respond properly to IFN-γ and develop severe infections with nontuberculous mycobacteria (NTM). IFN-γ and IFN-α are known to signal through STAT1 and activate many downstream effector genes in common. Therefore, we added IFN-α for treatment of patients with disseminated mycobacterial disease in an effort to complement their IFN-γ signaling defect. We treated four patients with IFN-γR deficiency with adjunctive IFN-α therapy in addition to best available antimicrobial therapy, with or without IFN-γ, depending on the defect. During IFN-α treatment, ex vivo induction of IFN target genes was detected. In addition, IFN-α driven gene expression in patients' cells and mycobacteria induced cytokine response were observed in vitro. Clinical responses varied in these patients. IFN-α therapy was associated with either improvement or stabilization of disease. In no case was disease exacerbated. In patients with profoundly impaired IFN-γ signaling who have refractory infections, IFN-α may have adjunctive anti-mycobacterial effects.

A multicentre randomized trial of the treatment of patients with pemphigus vulgaris with infliximab and prednisone compared with prednisone alone

BACKGROUND

Pemphigus vulgaris (PV) is a blistering disease and tumour necrosis factor-α has a role in its pathogenesis.

OBJECTIVES

To evaluate the safety of infliximab (IFX) with prednisone compared with prednisone alone in the treatment of PV. In addition, treatment response was assessed and mechanistic studies were performed.

METHODS

Subjects with PV who had ongoing disease activity while being maintained on prednisone were randomized to receive either IFX or placebo in addition to prednisone. Response status and immunoglobulin (Ig) G anti-desmoglein (Dsg)1 and Dsg3 antibodies were assessed at 18 and 26 weeks.

RESULTS

Ten subjects were randomized to each group. There were no safety signals during the course of the study. At week 18, one subject in each group had responded. At week 26, three IFX-treated subjects vs. none in the placebo group had responded (P = 0·21). At weeks 18 and 26, the median IgG anti-Dsg1 and anti-Dsg3 levels were lower in the IFX-treated patients [IgG anti-Dsg-1 (week 18, P = 0·035; week 26, P = 0·022); IgG anti-Dsg3 (week 18, P = 0·035; week, 26 P = 0·05)].

CONCLUSIONS

This study is limited by the relatively small sample size. There was no significant difference between study arms in the proportion of subjects with treatment-related adverse events > grade 3. IFX therapy was not shown to be effective for the treatment of patients with PV in this randomized, placebo-controlled trial, although IFX treatment may be associated with a decrease in anti-Dsg1 and Dsg3 antibodies.

Randomized controlled trial of atorvastatin in clinically isolated syndrome: the STAyCIS study

OBJECTIVE

To test efficacy and safety of atorvastatin in subjects with clinically isolated syndrome (CIS).

METHODS

Subjects with CIS were enrolled in a phase II, double-blind, placebo-controlled, 14-center randomized trial testing 80 mg atorvastatin on clinical and brain MRI activity. Brain MRIs were performed quarterly. The primary endpoint (PEP) was development of ≥ 3 new T2 lesions, or one clinical relapse within 12 months. Subjects meeting the PEP were offered additional weekly interferon β-1a (IFNβ-1a).

RESULTS

Due to slow recruitment, enrollment was discontinued after 81 of 152 planned subjects with CIS were randomized and initiated study drug. Median (interquartile range) numbers of T2 and gadolinium-enhancing (Gd) lesions were 15.0 (22.0) and 0.0 (0.0) at baseline. A total of 53.1% of atorvastatin recipients (n = 26/49) met PEP compared to 56.3% of placebo recipients (n = 18/32) (p = 0.82). Eleven atorvastatin subjects (22.4%) and 7 placebo subjects (21.9%) met the PEP by clinical criteria. Proportion of subjects who did not develop new T2 lesions up to month 12 or to starting IFNβ-1a was 55.3% in the atorvastatin and 27.6% in the placebo group (p = 0.03). Likelihood of remaining free of new T2 lesions was significantly greater in the atorvastatin group compared with placebo (odds ratio [OR] = 4.34, p = 0.01). Likelihood of remaining free of Gd lesions tended to be higher in the atorvastatin group (OR = 2.72, p = 0.11). Overall, atorvastatin was well tolerated. No clear antagonistic effect of atorvastatin plus IFNβ-1a was observed on MRI measures.

CONCLUSION

Atorvastatin treatment significantly decreased development of new brain MRI T2 lesion activity, although it did not achieve the composite clinical and imaging PEP.

CLASSIFICATION OF EVIDENCE

This study provided Class II evidence that atorvastatin did not reduce the proportion of patients with CIS meeting imaging and clinical criteria for starting immunomodulating therapy after 12 months, compared to placebo. In an analysis of a secondary endpoint (Class III), atorvastatin was associated with a reduced risk for developing new T2 lesions.

Regulation of human hsp90alpha gene expression

Mammalian HSP90alpha and HSP90beta are encoded by two individual genes. On the basis of the upstream sequences of the human hsp90alpha gene, GenBank accession number U25822, we have constructed CAT reporter plasmids driven by individual fragments of the hsp90alpha gene. We found that (1) the proximal heat shock element complex located at -96/-60 enhances hsp90alpha promoter expression; (2) heat shock induction depends upon the coexistence of distal heat shock element at -1031/-1022 and the proximal heat shock element complex of the hsp90alpha gene; (3) unlike hsp90beta, downstream sequences of the transcription start site inhibit hsp90alpha expression. We conclude that the regulatory mechanisms for the expression of hsp90alpha and hsp90beta genes are different.

NFATc1 promotes prostate tumorigenesis and overcomes PTEN loss-induced senescence

Despite recent insights into prostate cancer (PCa)-associated genetic changes, full understanding of prostate tumorigenesis remains elusive due to complexity of interactions among various cell types and soluble factors present in prostate tissue. We found upregulation of Nuclear Factor of Activated T Cells c1 (NFATc1) in human PCa and cultured PCa cells, but not in normal prostates and non-tumorigenic prostate cells. To understand the role of NFATc1 in prostate tumorigenesis in situ, we temporally and spatially controlled the activation of NFATc1 in mouse prostate and showed that such activation resulted in prostatic adenocarcinoma with features similar to those seen in human PCa. Our results indicate that the activation of a single transcription factor, NFATc1 in prostatic luminal epithelium to PCa can affect expression of diverse factors in both cells harboring the genetic changes and in neighboring cells through microenvironmental alterations. In addition to the activation of oncogenes c-MYC and STAT3 in tumor cells, a number of cytokines and growth factors, such as IL1β, IL6, and SPP1 (Osteopontin, a key biomarker for PCa), were upregulated in NFATc1-induced PCa, establishing a tumorigenic microenvironment involving both NFATc1 positive and negative cells for prostate tumorigenesis. To further characterize interactions between genes involved in prostate tumorigenesis, we generated mice with both NFATc1 activation and Pten inactivation in prostate. We showed that NFATc1 activation led to acceleration of Pten-null–driven prostate tumorigenesis by overcoming the PTEN loss–induced cellular senescence through inhibition of p21 activation. This study provides direct in vivo evidence of an oncogenic role of NFATc1 in prostate tumorigenesis and reveals multiple functions of NFATc1 in activating oncogenes, in inducing proinflammatory cytokines, in oncogene addiction, and in overcoming cellular senescence, which suggests calcineurin-NFAT signaling as a potential target in preventing PCa.

Expression of RGS4 splice variants in dorsolateral prefrontal cortex of schizophrenic and bipolar disorder patients

BACKGROUND

Previous molecular and genetic studies have implicated RGS4 (regulator of G protein signaling 4) in schizophrenia (SCZ) and bipolar disorder (BPD), but the role of RGS4 in the pathology of the two disorders remains controversial. Recently we identified five different RGS4 splice variants in the human brain. In this study we tested whether expression of specific RGS4 splice variants is altered in the prefrontal cortex of schizophrenic and BPD subjects.

METHODS

Quantitative real-time polymerase chain reaction was used to detect overall RGS4 expression and the messenger RNA levels of the four RGS4 splice variants in the prefrontal cortex of schizophrenic (n = 27), BPD (n = 27), and normal (n = 27) subjects.

RESULTS

Compared with the normal group, the expression of a specific splice variant RGS4-3 was decreased in the dorsolateral prefrontal cortex of the SCZ group, whereas overall RGS4 expression and expression of other RGS4 isoforms did not differ significantly between the control and SCZ groups. The messenger RNA levels of RGS4 isoforms did not change between the control group and the BPD group.

CONCLUSIONS

Our results suggest the possibility that alterations in the expression of RGS4-3 contribute to the development of SCZ.