Ablation of the microglial protein DOCK2 reduces amyloid burden in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) neuropathology is characterized by innate immune activation primarily through prostaglandin E2 (PGE₂) signaling. Dedicator of cytokinesis 2 (DOCK2) is a guanyl nucleotide exchange factor expressed exclusively in microglia in the brain and is regulated by PGE₂ receptor EP2. DOCK2 modulates microglia cytokine secretion, phagocytosis, and paracrine neurotoxicity. EP2 ablation in experimental AD results in reduced oxidative damage and amyloid beta (Aβ) burden. This discovery led us to hypothesize that genetic ablation of DOCK2 would replicate the anti-Aβ effects of loss of EP2 in experimental AD. To test this hypothesis, we crossed mice that lacked DOCK2 (DOCK2 −/−), were hemizygous for DOCK2 (DOCK2 +/−), or that expressed two DOCK2 genes (DOCK2 +/+) with APPswe-PS1Δe9 mice (a model of AD). While we found no DOCK2-dependent differences in cortex or in hippocampal microglia density or morphology in APPswe-PS1Δe9 mice, cerebral cortical and hippocampal Aβ plaque area and size were significantly reduced in 10-month-old APPswe-PS1Δe9/DOCK2 −/− mice compared with APPswe-PS1Δe9/DOCK2 +/+ controls. DOCK2 hemizygous APPswe-PS1Δe9 mice had intermediate Aβ plaque levels. Interestingly, soluble Aβ₄₂ was not significantly different among the three genotypes, suggesting the effects were mediated specifically in fibrillar Aβ. In combination with earlier cell culture results, our in vivo results presented here suggest DOCK2 contributes to Aβ plaque burden via regulation of microglial innate immune function and may represent a novel therapeutic target for AD.     

Changes in Expression of Connexin 32, Bile Canaliculus-Like Structures,and Localization of Alkaline Phosphatase in Primary Cultures of Fetal Rat Hepatocytes

We devised an experimental design in primary cultures of fetal rat hepatocytes for studying hepatocyte differentiation over a short period. In the present study, hepatocytes were first cultured for 3 days in dexamethasone-supplemented medium and then for an additional 3 days in dexamethasone- or epidermal growth factor-supplemented medium. In hepatocytes cultured continuously in dexamethasone-supplemented medium, the expression of connexin 32 increased and bile canaliculus-like structures and localization of alkaline phosphatase in the plasma membrane around bile canaliculus-like structures were maintained. Few cells incorporated bromodeoxyuridine. On the other hand, in most of the hepatocytes cultured in epidermal growth factor-supplemented medium, the expression of connexin 32 was minimally recognized, bile canaliculus-like structures were shortened or eliminated, and alkaline phosphatase was localized as numerous fine spots throughout the cytoplasm. More than 20% of all hepatocytes incorporated bromodeoxyuridine.The present study suggests that in hepatocytes, there is a close relationship among connexin 32 expression, the maintenance of bile canaliculus-like structures, and the localization of alkaline phosphatase to the plasma membrane around the bile canaliculus-like structures, and this indicates that the present experimental model is useful for studying hepatocyte differentiation over a short period.     

CCR5 Δ 32 mutation is not prevalent in Iranians with chronic HBV infection

CCR5 is an important chemokine receptor involved in the recruitment of specific anti‐viral immune cells (e.g., NK cells and T cytotoxic cells) to the liver. Previous studies indicated that the Δ 32 mutation in CCR5 gene led to inactivation of CCR5. Several conflicting studies have suggested that this mutation may be associated with either recovery or persistence of HBV infection. The main purpose of this study was to compare the frequency of the Δ 32 mutation within the CCR5 gene in a group of patients infected chronically with HBV with healthy individuals from South‐East of Iran. Sixty patients with chronic HBV infection as well as 300 age‐, and sex‐match healthy individuals were enrolled in this study. Gap‐PCR was applied to determine the frequency of CCR5 Δ 32 mutation in both groups. The results demonstrated that none of the patients infected with HBV carried the CCR5 Δ 32 mutation while, 3 (1%) of the healthy individuals were found to be heterozygotic for this mutation. The CCR5 Δ 32 mutation is not a prevalent mutation in either the patients infected chronically with HBV or their health counterparts in the South‐East region of Iran. This may be attributed to either different genetic settings of the investigated population or lack of any significant correlation between this mutation and HBV pathogenicity. J. Med. Virol. 85: 964–968, 2013. © 2013 Wiley Periodicals, Inc.     

Effect of Immunization with Common Enterobacterial Antigen on Experimental Salmonella Typhimurium Infection of Mice

Common enterobacterial antigen (CA) extracted from cultures of Escherichia & serogroups 014 and 0111 was administered intraperitoneally to Swiss white albino and C57BL/6Ha mice. Seven days after the last of 3 injections, the mice were challenged intraperitoneally with 100 LD₅₀ Salmonella typhimurium C5S. Numbers of living mice were recorded daily and compared with the numbers of living mice in control groups which had received extracts of Staphylococcus aureus or Pseudomonas aeruginosa, devoid of CA, or buffered saline. Both mouse strains immunized with CA showed transient but statistically significant protection; the Swiss white albino mice were the better protected. Further studies are needed to identify the role of CA in cellular and humoral immunity against salmonelloeis.     

The prevalence of nonalcoholic fatty liver disease in Chinese adults screened by vibration controlled transient elastography and its diagnostic discrepancy compared with ultrasound

BackgroundThe prevalence of non-alcoholic fatty liver disease (NAFLD) in China as assessed using vibration-controlled transient elastography (VCTE) and its consistency with ultrasound is still unknown. We aimed to conduct a head-to-head comparison of consecutive measurements of NAFLD with ultrasound or VCTE to evaluate the discrepancy in the prevalence and distribution of NAFLD screened by two non-invasive techniques.MethodsWe collected VCTE and ultrasound examination data from 4,388 participants who underwent health check-ups at the Health Promotion Center of Jiangsu Province Hospital between January 2017 and December 2019. The major outcome was the presence of hepatic steatosis, which was defined as a median controlled attenuation parameter (CAP) ≥ 248 dB/m by VCTE or the definition of steatosis by ultrasound.ResultsAmong the 4,388 participants, 2,214 were diagnosed with NAFLD by VCTE (CAP ≥ 248 dB/m, 50.46%). Participants with severe steatosis (CAP ≥ 280 dB/m) were commonly male (77.94% vs. 50.38%, P < 0.001), were obese (45.09% vs. 1.79%, P < 0.001), had a worse metabolic profile, had elevated liver enzyme levels, and had advanced fibrosis. The prevalence of ultrasound-diagnosed NAFLD was 56.42%. After consistency analysis, VCTE and ultrasound showed moderate agreement regarding the diagnosis of NAFLD (κ = 0.475). We then compared the characteristics and clinical features of the four groups classified by the diagnosis results of the two techniques. NAFLD participants diagnosed by VCTE only were older, more obese, and had worse metabolic and biochemical profiles than NAFLD participants diagnosed by ultrasound only; in particular, the former had a higher proportion of abnormal alanine aminotransferase and aspartate aminotransferase levels and a higher proportion of advanced fibrosis than the latter.ConclusionsMore than half of Chinese adults were affected by NAFLD according to VCTE. Screening based on VCTE is more likely to identify NAFLD patients with severe clinical features than ultrasound. Therefore, VCTE is a more practical non-invasive tool for the screening and follow-up of NAFLD in China.     

Integrated nanotechnology platform for tumor-targeted multimodal imaging and therapeutic cargo release

A major challenge of targeted molecular imaging and drug delivery in cancer is establishing a functional combination of ligand-directed cargo with a triggered release system. Here we develop a hydrogel-based nanotechnology platform that integrates tumor targeting, photon-to-heat conversion, and triggered drug delivery within a single nanostructure to enable multimodal imaging and controlled release of therapeutic cargo. In proof-of-concept experiments, we show a broad range of ligand peptide-based applications with phage particles, heat-sensitive liposomes, or mesoporous silica nanoparticles that self-assemble into a hydrogel for tumor-targeted drug delivery. Because nanoparticles pack densely within the nanocarrier, their surface plasmon resonance shifts to near-infrared, thereby enabling a laser-mediated photothermal mechanism of cargo release. We demonstrate both noninvasive imaging and targeted drug delivery in preclinical mouse models of breast and prostate cancer. Finally, we applied mathematical modeling to predict and confirm tumor targeting and drug delivery. These results are meaningful steps toward the design and initial translation of an enabling nanotechnology platform with potential for broad clinical applications.A long-term goal in contemporary cancer nanomedicine has been to design and generate drug delivery systems that improve the narrow therapeutic window associated with conventional chemotherapeutics (1, 2). Conceptually, several nanotechnology-based entity candidates, including protocells (3), biosynthetic nanoparticles (NPs), viruses, and liposome-based nanoparticles, could be targeted for active delivery through a defined cell surface ligand receptor system and/or physically triggered for finely tuned cargo release (2, 4, 5).Numerous efforts have been made to functionalize NPs by combining them with antibodies, aptamers, peptides, vitamins, or carbohydrates (6–8), but the majority of studies involve untargeted nanoplatforms (4, 9). In practice, targeting NPs is far from trivial, and ongoing challenges include synthesis and purification, selection of an appropriate ligand receptor, and specific composition for NP conjugation. Even the conjugation reaction itself may alter the binding of the tumor-targeting moiety to its receptor through conformational changes, steric freedom restriction, or orientation distortion (10, 11). Unfortunately, the cost-to-benefit ratio of these modifications often elevate the complexity of the NP synthesis, complicating regulatory hurdles because of formulations that are heterogeneous or difficult to reproduce (10, 12, 13).To minimize such drawbacks, NPs can be functionalized via virus-based nanoplatforms as an alternative for targeted cargo delivery (14–16). In particular, filamentous bacteriophage (phage)—a prokaryotic virus—is an attractive candidate to develop a bionanomedicine for cancer therapeutics because phage particles are cost-effectively produced with biological uniformity, as well as being physically robust and stable under harsh conditions (17). Notably, phage-based nanoplatforms are biocompatible and nonpathogenic with eukaryotic organisms and are able to preserve the desired cell targeting and internalization (18). Moreover, phage particles are ideal for incorporating other NPs, which can be released after reaching the tumor site. An admixture of colloidal gold NP (AuNP) with phage particles spontaneously organizes into hydrogel network-like fractal structures (19, 20). These hydrogel networks offer convenient multifunctional integration within a single entity for tumor targeting, enhanced fluorescence and dark-field microscopy, near-infrared (NIR) photon-to-heat conversion, and surface-enhanced Raman scattering (SERS)-based detection (20, 21).In the present work, we developed a tumor targeting theranostic (meaning a combination of therapeutics and diagnostics) hydrogel-based nanoplatform that enables ligand-directed tumor targeting, multimodal imaging capability, and triggered therapeutic cargo release. Our data suggest that targeted hydrogel photothermal therapy represents a functional theranostic approach (fostering “see and treat, treat and see”) in the diagnosis and management of tumors.     

Expression of miR-32 in human non-small cell lung cancer and its correlation with tumor progression and patient survival

Introduction: miR-32 has recently been found to be implicated in many critical processes in various types of human cancer. However, its clinical significance in human non-small cell lung cancer (NSCLC) has not yet been elucidated. In the present study, we investigated the expression of miR-32 in NSCLC and analyzed its association with clinical features and prognosis of NSCLC patients. Methods: Quantitative real-time PCR (qRT-PCR) was used to measure expression level of miR-32 in lung cancer cell lines, normal bronchial epithelial cells, 90 pairs of tumor samples and adjacent non-tumor tissues. To determine its prognostic value, overall survival was evaluated using the Kaplan-Meier method. Univariate and multivariate analysis were performed using the Cox proportional hazard analysis. Results: The expression of miR-32 was significantly decreased in lung cancer cell lines and NSCLC tissues compared with normal bronchial epithelial cells and adjacent non-tumor tissues (P < 0.05). This reduction of miR-32 was associated with tumor stage and lymph node metastasis (P < 0.05). Moreover, Kaplan-Meier analysis demonstrated that patients with low miR-32 expression had shorter overall survival time than those with high miR-32 expression (P < 0.05). Univariate analysis revealed statistically significant correlations between overall survival and miR-32 level, tumor stage and lymph node metastasis (P < 0.05). Furthermore, miR-32 levels, tumor stage and lymph node metastasis were independently associated with overall survival (P < 0.05). Conclusions: Our results provided the first evidence that down-regulation of miR-32 was correlated with NSCLC progression, and miR-32 might be a potential molecular biomarker for predicting the prognosis of patients.     

ShcC proteins: Brain aging and beyond

To date, most studies of Shc family of signaling adaptor proteins have been focused on the near-ubiquitously expressed ShcA, indicating its relevance to age-related diseases and longevity. Although the role of the neuronal ShcC protein is much less investigated, accumulated evidence suggests its importance for neuroprotection against such aging-associated conditions as brain ischemia and oxidative stress. Here, we summarize more than decade of studies on the ShcC expression and function in normal brain, age-related brain pathologies and immune disorders with a focus on the interactions of ShcC with signaling proteins/pathways, and the possible implications of these interactions for changes associated with aging.     

Soluble interleukin-6 receptor is elevated during influenza A virus infection and mediates the IL-6 and IL-32 inflammatory cytokine burst

Influenza A virus (IAV) infection is a major worldwide public health problem. However, the factors involved in mediating the inflammatory response to this infection and their relationships remain poorly understood. Here, we show that IAV infection stimulates the expression of the soluble IL-6 receptor (sIL-6R), a multifunctional protein involved in IL-6 signaling. Interestingly, sIL-6R expression upregulated the levels of its own ligand, IL-6 and those of the pro-inflammatory cytokine IL-32. shRNA-mediated knockdown of sIL-6R suppressed IL-6 and IL-32, indicating that this regulation is dependent on sIL-6R during IAV infection. Furthermore, our results demonstrate that IL-32 participates in a negative feedback loop that inhibits sIL-6R while upregulating IL-6 expression during IAV infection. Therefore, we show that sIL-6R is a critical cellular factor involved in the acute inflammatory response to viral infection.     

Discovery of Surfactant-Like Peptides from a Phage-Displayed Peptide Library

Peptides with specific affinities for various materials have been identified in the past three decades and utilized in materials science and engineering. A peptide’s capability to specifically interact with materials is not naturally derived but screened from a biologically constructed peptide library displayed on phages or cells. To date, due to limitations in the screening procedure, the function of screened peptides has been primarily limited to the affinity for target materials. Herein, we demonstrated the screening of surfactant-like peptides from a phage-displayed peptide library. A screened phage clone displaying a peptide showed high activity for accumulating at emulsion surfaces with certain assembled structures, resulting in stable emulsions. The surface tension for the solution of the chemically synthesized peptide decreased with increasing peptide concentration, demonstrating certain surface activity, which corresponded to the ability to decrease the surface tension of liquids (e.g., water), owing to the accumulation of molecules at the air–liquid or liquid–liquid interface. Peptides with a randomized sequence did not lower the surface tension, indicating the essential role of amino acid sequences in surface activity. Our strategy for identifying novel functional peptides from a phage-displayed peptide library can be used to expand the applicability of peptidyl materials and biosurfactants.