Mycobacterium kansasii-induced death of murine macrophages involves endoplasmic reticulum stress responses mediated by reactive oxygen species generation or calpain activation

Although pathogenic mechanisms of tuberculosis have been extensively studied, little is known about the pathogenic mechanisms of Mycobacterium kansasii. In this work the influence of virulence and ER-stress mediated apoptosis of macrophages during two different strains of M. kansasii infection was investigated. We show that M. kansasii infection is associated with ER stress-mediated apoptosis in the murine macrophage cell line RAW 264.7. Infection of RAW 264.7 cells in vitro with apoptosis-inducing a clinical isolate of M. kansasii SM-1 (SM-1) resulted in strong induction of ER stress responses compared with M. kansasii type strain (ATCC 12478)-infected RAW 264.7 cells. Interestingly, inhibition of calpain prevented the induction of CHOP and Bip in ATCC 12478-infected RAW 264.7 cells but not in RAW 264.7 cells infected with SM-1. In contrast, reactive oxygen species (ROS) were significantly increased only in RAW 264.7 cells infected with SM-1. We propose that ROS generation is important for triggering ER stress-mediated apoptosis during SM-1 infection, whereas ATCC 12478-induced, ER stress-mediated apoptosis is associated with calpain activation. Our results demonstrate that the ER stress pathway plays important roles in the pathogenesis of M. kansasii infections, and that different strains of M. kansasii induce different patterns of ER stress-mediated apoptosis.     

Synthesis and structural characterization of silver nanoparticles using bacterial exopolysaccharide and its antimicrobial activity against food and multidrug resistant pathogens

A green, simple, and effective approach was performed to synthesize potent silver nanoparticles (SNPs) using bacterial exopolysaccharide as both a reducing and stabilizing agent. The synthesized SNPs were characterized using UV-vis spectroscopy, transmission electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and Fourier-transform-infrared spectra analyses. The SNPs varied in shape and were multidispersed with a mean diameter of 10 nm ranging from 2 to 15 nm and were stable up to 2 months at room temperature. The antimicrobial activity of the SNPs was analyzed against bacterial and fungal pathogens using the agar well diffusion method. Dose dependent inhibition was observed for all bacterial pathogens. The multidrug resistant pathogens P. aeruginosa and K. pneumonia were found to be more susceptible to the SNPs than the food borne pathogen L. monocytogenes. The fungi Aspergillus spp. exhibited a maximum zone of inhibition compared to that of Penicillum spp. These results suggest that exopolysaccharide-stabilized SNPs can be used as an antimicrobial agent for various biomedical applications.     

Caloric restriction augments radiation efficacy in breast cancer

Dietary modification such as caloric restriction (CR) has been shown to decrease tumor initiation and progression. We sought to determine if nutrient restriction could be used as a novel therapeutic intervention to enhance cytotoxic therapies such as radiation (IR) and alter the molecular profile of triple-negative breast cancer (TNBC), which displays a poor prognosis. In two murine models of TNBC, significant tumor regression is noted with IR or diet modification, and a greater regression is observed combining diet modification with IR. Two methods of diet modification were compared, and it was found that a daily 30% reduction in total calories provided more significant tumor regression than alternate day feeding. At the molecular level, tumors treated with CR and IR showed less proliferation and more apoptosis. cDNA array analysis demonstrated the IGF-1R pathway plays a key role in achieving this physiologic response, and multiple members of the IGF-1R pathway including IGF-1R, IRS, PIK3ca and mTOR were found to be downregulated. The innovative use of CR as a novel therapeutic option has the potential to change the biology of tumors and enhance the opportunity for clinical benefit in the treatment of patients with TNBC.     

Proteomic analysis of kidneys from selenoprotein M transgenic rats in response to increased bioability of selenium

Background

To characterize changes in global protein expression in kidneys of transgenic rats overexpressing human selenoprotein M (SelM) in response to increased bioabivility of selenium (Sel), total proteins extracted from kidneys of 10-week-old CMV/hSelM Tg and wild-type rats were separated by 2-dimensional gel electrophoresis and measured for changes in expression.

Results

Ten and three proteins showing high antioxidant enzymatic activity were up- and down-regulated, respectively, in SelM-overexpressing CMV/hSelM Tg rats compared to controls based on an arbitrary 2-fold difference. Up-regulated proteins included LAP3, BAIAP2L1, CRP2, CD73 antigen, PDGF D, KIAA143 homolog, PRPPS-AP2, ZFP313, HSP-60, and N-WASP, whereas down-regulated proteins included ALKDH3, rMCP-3, and STC-1. After Sel treatment, five of the up-regulated proteins were significantly increased in expression in wild-type rats, whereas there were no changes in CMV/hSelM Tg rats. Only two of the down-regulated proteins showed reduced expression in wild-type and Tg rats after Sel treatment.

Conclusions

These results show the primary novel biological evidences that new functional protein groups and individual proteins in kidneys of Tg rats relate to Sel biology including the response to Sel treatment and SelM expression.     

Somatic cell transformation into stem cell-like cells induced by different microenvironments

Development of induced pluripotent stem cell (iPSC) technology introduced a novel way to derive pluripotent stem cells, but the genetic manipulation required to generate iPSCs may lead to uncontrolled tumorigenesis of the established cells and thus limit clinical feasibility of the technology. Numerous attempts have been made to date, and alternative reprogramming of somatic cells to reactivate cellular plasticity after differentiation has been suggested. As a result, it had become clear that cell-to-cell interactions and specific acellular environments can be utilized for somatic cell reprogramming. In our previous studies, embryonic stem cell (ESC)-like cells could be derived from transforming ovarian cells and fetal fibroblasts by cell-to-cell interaction or specific cell-mediated microenvironmental factor(s). This cellular event was induced without undertaking genetic manipulation of progenitor cells. Several differences were found between the cellular properties of niche-induced, ESC-like cells and those of genetically manipulated iPSCs and the referenced ESCs. Thus, we provided evidence that terminally differentiated somatic cells either acquire pluripotency-like activity or possess cellular and genetic plasticity under a specific microenvironment and/or cell-to-cell interaction. In this minireview, we discuss derivation of stem cell-like cells under specific microenvironmental conditions in terms of technical perspectives and limitations.     

Mutation at Intronic Repeats of the Ataxia-Telangiectasia Mutated (ATM) Gene and ATM Protein Loss in Primary Gastric Cancer with Microsatellite Instability

Ataxia-telangiectasia mutated (ATM) is a Ser/Thr protein kinase that plays a critical role in DNA damage-induced signaling and initiation of cell cycle checkpoint signaling in response to DNA-damaging agents such as ionizing radiation. We have previously reported the ATM protein loss by immunohistochemistry (IHC) in 16% of human gastric cancer (GC) tissue. We hypothesized that ATM gene intron mutations targeted by microsatellite instability (MSI) cause ATM protein loss in a subset of GC. We studied mononucleotide mutations at the intron of ATM gene, ATM IHC and MSI in GC. Ten human gastric cancer cell lines were studied for the ATM gene mutation at introns, RT-PCR, direct sequencing, and immunohistochemistry. GC tissues of 839 patients were analyzed for MSI and ATM IHC. Among them, 604 cases were analyzed for the ATM mutations at introns preceding exon 6, exon 10 and exon 20. Two human GC cell lines (SNU-1 and -638) showed ATM intron mutations, deletion in RT-PCR and direct sequencing, and ATM protein loss by IHC. The frequencies of ATM mutation, MSI, and ATM protein loss were 12.9% (78/604), 9.2% (81/882) and 15.2% (134/839), respectively. Analysis of associations among MSI, ATM gene mutation, and ATM protein loss revealed highly co-existing ATM gene alterations and MSI. ATM intron mutation and ATM protein loss were detected in 69.3% (52/75) and 53.3% (40/75) of MSI positive GC. MSI positivity and ATM protein loss were present in 68.4% (52/76) and 48.7% (37/76) of GC with ATM intron mutation. ATM mutation and ATM protein loss had characteristics of old age, distal location of tumor, large tumor size, and histologic intestinal type. Our study might be interpreted as that ATM gene mutation at intron might be targeted by MSI and lead to ATM protein loss in a selected group of GC.     

Associations between Lifetime Traumatic Events and Subsequent Chronic Physical Conditions: A Cross-National,Cross-Sectional Study

Background

Associations between lifetime traumatic event (LTE) exposures and subsequent physical ill-health are well established but it has remained unclear whether these are explained by PTSD or other mental disorders. This study examined this question and investigated whether associations varied by type and number of LTEs, across physical condition outcomes, or across countries.

Methods

Cross-sectional, face-to-face household surveys of adults (18+) were conducted in 14 countries (n = 38, 051). The Composite International Diagnostic Interview assessed lifetime LTEs and DSM-IV mental disorders. Chronic physical conditions were ascertained by self-report of physician''s diagnosis and year of diagnosis or onset. Survival analyses estimated associations between the number and type of LTEs with the subsequent onset of 11 physical conditions, with and without adjustment for mental disorders.

Findings

A dose-response association was found between increasing number of LTEs and odds of any physical condition onset (OR 1.5 [95% CI: 1.4–1.5] for 1 LTE; 2.1 [2.0–2.3] for 5+ LTEs), independent of all mental disorders. Associations did not vary greatly by type of LTE (except for combat and other war experience), nor across countries. A history of 1 LTE was associated with 7/11 of the physical conditions (ORs 1.3 [1.2–1.5] to 1.7 [1.4–2.0]) and a history of 5+ LTEs was associated with 9/11 physical conditions (ORs 1.8 [1.3–2.4] to 3.6 [2.0–6.5]), the exceptions being cancer and stroke.

Conclusions

Traumatic events are associated with adverse downstream effects on physical health, independent of PTSD and other mental disorders. Although the associations are modest they have public health implications due to the high prevalence of traumatic events and the range of common physical conditions affected. The effects of traumatic stress are a concern for all medical professionals and researchers, not just mental health specialists.     

Molecular Detection of Ehrlichia canis in Dogs in Malaysia

An epidemiological study of Ehrlichia canis infection in dogs in Peninsular Malaysia was carried out using molecular detection techniques. A total of 500 canine blood samples were collected from veterinary clinics and dog shelters. Molecular screening by polymerase chain reaction (PCR) was performed using genus-specific primers followed by PCR using E. canis species-specific primers. Ten out of 500 dogs were positive for E. canis. A phylogenetic analysis of the E. canis Malaysia strain showed that it was grouped tightly with other E. canis strains from different geographic regions. The present study revealed for the first time, the presence of genetically confirmed E. canis with a prevalence rate of 2.0% in naturally infected dogs in Malaysia.