374 research outputs found
Xeroderma Pigmentosum Group C Deficiency Alters Cigarette Smoke DNA Damage Cell Fate and Accelerates Emphysema Development
Cigarette smoke (CS) exposure is a major risk factor for the development of emphysema, a common disease characterized by loss of cells comprising the lung parenchyma. The mechanisms of cell injury leading to emphysema are not completely understood but are thought to involve persistent cytotoxic or mutagenic DNA damage induced by CS. Using complementary cell culture and mouse models of CS exposure, we investigated the role of the DNA repair protein, xeroderma pigmentosum group C (XPC), on CS-induced DNA damage repair and emphysema. Expression of XPC was decreased in mouse lungs after chronic CS exposure and XPC knockdown in cultured human lung epithelial cells decreased their survival after CS exposure due to activation of the intrinsic apoptosis pathway. Similarly, cell autophagy and apoptosis were increased in XPC-deficient mouse lungs and were further increased by CS exposure. XPC deficiency was associated with structural and functional changes characteristic of emphysema, which were worsened by age, similar to levels observed with chronic CS exposure. Taken together, these findings suggest that repair of DNA damage by XPC plays an important and previously unrecognized role in the maintenance of alveolar structures. These findings support that loss of XPC, possibly due to chronic CS exposure, promotes emphysema development and further supports a link between DNA damage, impaired DNA repair, and development of emphysema
Interaction of Model Lipid Vesicles with Alveolar Macrophages
Macrophages are a type of white blood cells that play key roles in host defense by recognizing and engulfing foreign and apoptotic bodies. To accomplish this task, they rely on complex molecular interactions involving both lipids and proteins. Previous studies have shown that surface exposure of phosphatidylserine by apoptotic cells is required for their successful clearance, suggesting specific lipid-protein interactions at least for the initiation of phagocytosis of apoptotic cells. However, macrophages can engulf foreign and apoptotic bodies that substantially vary in size suggesting that non-specific interactions over a range of length scales may be relevant. The purpose of our study is to investigate the correlation between physical properties of lipid bilayers and their engulfment by macrophages. We modify bilayer properties systematically as a function of phospholipid headgroup composition and by addition of ceramide and cholesterol. We use a combination of scattering and spectroscopic methods to quantify lipid interactions and flow cytometry to measure engulfment rates. This study can help distinguish between the role of lipids and proteins in clearance of apoptotic and foreign particles
Smoking exposure induces human lung endothelial cell adaptation to apoptotic stress
Prolonged exposure to cigarette smoking is the main risk factor for emphysema, a component of chronic obstructive pulmonary diseases (COPDs) characterized by destruction of alveolar walls. Moreover, smoking is associated with pulmonary artery remodeling and pulmonary hypertension, even in the absence of COPD, through as yet unexplained mechanisms. In murine models, elevations of intra- and paracellular ceramides in response to smoking have been implicated in the induction of lung endothelial cell apoptosis, but the role of ceramides in human cell counterparts is yet unknown. We modeled paracrine increases (outside-in) of palmitoyl ceramide (Cer16) in primary human lung microvascular cells. In naive cells, isolated from nonsmokers, Cer16 significantly reduced cellular proliferation and induced caspase-independent apoptosis via mitochondrial membrane depolarization, apoptosis-inducing factor translocation, and poly(ADP-ribose) polymerase cleavage. In these cells, caspase-3 was inhibited by ceramide-induced Akt phosphorylation, and by the induction of autophagic microtubule-associated protein-1 light-chain 3 lipidation. In contrast, cells isolated from smokers exhibited increased baseline proliferative features associated with lack of p16(INK4a) expression and Akt hyperphosphorylation. These cells were resistant to Cer16-induced apoptosis, despite presence of both endoplasmic reticulum stress response and mitochondrial membrane depolarization. In cells from smokers, the prominent up-regulation of Akt pathways inhibited ceramide-triggered apoptosis, and was associated with elevated sphingosine and high-mobility group box 1, skewing the cell's response toward autophagy and survival. In conclusion, the cell responses to ceramide are modulated by an intricate cross-talk between Akt signaling and sphingolipid metabolites, and profoundly modified by previous cigarette smoke exposure, which selects for an apoptosis-resistant phenotype
Inhibition of acid sphingomyelinase disrupts LYNUS signaling and triggers autophagy
Activation of the lysosomal ceramide-producing enzyme, acid sphingomyelinase (ASM), by various stresses is centrally involved in cell death and has been implicated in autophagy. We set out to investigate the role of the baseline ASM activity in maintaining physiological functions of lysosomes, focusing on the lysosomal nutrient-sensing complex (LYNUS), a lysosomal membrane-anchored multiprotein complex that includes mammalian target of rapamycin (mTOR) and transcription factor EB (TFEB). ASM inhibition with imipramine or sphingomyelin phosphodiesterase 1 (SMPD1) siRNA in human lung cells, or by transgenic Smpd1+/- haploinsufficiency of mouse lungs, markedly reduced mTOR- and P70-S6 kinase (Thr 389)-phosphorylation and modified TFEB in a pattern consistent with its activation. Inhibition of baseline ASM activity significantly increased autophagy with preserved degradative potential. Pulse labeling of sphingolipid metabolites revealed that ASM inhibition markedly decreased sphingosine (Sph) and Sph-1-phosphate (S1P) levels at the level of ceramide hydrolysis. These findings suggest that ASM functions to maintain physiological mTOR signaling and inhibit autophagy and implicate Sph and/or S1P in the control of lysosomal function
Probation migration(s): Examining occupational culture in a turbulent field
In June 2014 approx. 54 per cent of the total probation service workforce in England and Wales were transferred to the newly created Community Rehabilitation Companies (CRCs) as part of the government’s plans to establish a market for offender management services. This marked the beginning of one of the largest and most significant migrations of criminal justice staff from the public to the private sector in England and Wales. This article presents findings from an ethnographic study of the formation of one of these CRCs through to the period immediately following the transfer into private ownership. The authors discuss the key features of this migration which are identified as ‘splitting and fracturing’, ‘adapting and forming’ and ‘exiting or accommodation’. It is contended that this development not only has significant implications for the future of probation services but also provides a unique example of the impact on an occupational culture of migration from the public to the private sector
Cancer incidence in HIV-infected versus uninfected veterans: Comparison of cancer registry and ICD-9 code diagnoses
Background: Given the growing interest in the cancer burden in persons living with HIV/AIDS, we examined the validity of data sources for cancer diagnoses (cancer registry versus International Classification of Diseases, Ninth Revision [ICD-9 codes]) and compared the association between HIV status and cancer risk using each data source in the Veterans Aging Cohort Study (VACS), a prospective cohort of HIV-infected and uninfected veterans from 1996 to 2008.
Methods: We reviewed charts to confirm potential incident cancers at four VACS sites. In the entire cohort, we calculated cancer-type-specific age-, sex-, race/ethnicity-, and calendar-period-standardized incidence rates and incidence rate ratios (IRR) (HIV-infected versus uninfected). We calculated standardized incidence ratios (SIR) to compare VACS and Surveillance, Epidemiology, and End Results rates.
Results: Compared to chart review, both Veterans Affairs Central Cancer Registry (VACCR) and ICD-9 diagnoses had approximately 90% sensitivity; however, VACCR had higher positive predictive value (96% versus 63%). There were 6,010 VACCR and 13,386 ICD-9 incident cancers among 116,072 veterans. Although ICD-9 rates tended to be double VACCR rates, most IRRs were in the same direction and of similar magnitude, regardless of data source. Using source, all cancers combined, most viral-infection-related cancers, lung cancer, melanoma, and leukemia had significantly elevated IRRs. Using ICD-9, eight additional IRRs were significantly elevated, most likely due to false positive diagnoses. Most ICD-9 SIRs were significantly elevated and all were higher than the corresponding VACCR SIR.
Conclusions: ICD-9 may be used with caution for estimating IRRs, but should be avoided when estimating incidence or SIRs. Elevated cancer risk based on VACCR diagnoses among HIV-infected veterans was consistent with other studies
Post-release reforms for short prison sentences: re-legitimising and widening the net of punishment
Transforming Rehabilitation (TR) promised a ‘revolution’ in the way offenders are managed, providing a renewed focus on short sentence prisoners. The TR reforms extends mandatory post-release supervision and tailored through-the-gate resettlement provisions to a group that has predominately faced a ‘history of neglect’ yet often present with the most acute needs within the criminal justice system. However, existing literature underlines that serving short sentences lack ‘utility’ and can be counter-productive to facilitating effective rehabilitation.
This article explores the purposes of providing post release supervision for short sentences, firstly exploring a previous attempt to reform short sentences; (the now defunct) ‘Custody Plus’ within the 2003 Criminal Justice Act and then the Offender Rehabilitation Act 2014 within the TR reforms. This article contends that both post release reforms have sought to re-affirm and re-legitimise prison as the dominant form of punishment in society- or what Carlen refers to as ‘carceral clawback’. This article will also use Cohen’s analysis on social control to establish that post release supervision will serve to ‘widen the net’ extend the period of punishment and oversight and will only reinforce a form of enforced ‘state obligated rehabilitation’ that will undermine efforts made to resettle short sentence prisoners
Association Between Depressive Disorders and Incident Acute Myocardial Infarction in Human Immunodeficiency Virus–Infected Adults
IMPORTANCE
With the advent of highly effective antiretroviral therapy and improved survival, human immunodeficiency virus (HIV)–infected people are living longer and are now at an increased risk for cardiovascular disease (CVD). There is an urgent need to identify novel risk factors and primary prevention approaches for CVD in HIV. Although depression is prevalent in HIV-infected adults and is associated with future CVD in the general population, its association with CVD events has not been examined in the HIV-infected population.
OBJECTIVE
To examine whether depressive disorders are prospectively associated with incident acute myocardial infarction (AMI) in a large cohort of adults with HIV.
DESIGN, SETTING, AND PARTICIPANTS
Included in this cohort study were 26 144 HIV-infected veterans without CVD at baseline (1998–2003) participating in the US Department of Veterans Affairs Veterans Aging Cohort Study from April 1, 2003, through December 31, 2009. At baseline, 4853 veterans (19%) with major depressive disorder (MDD; International Classification of Diseases, Ninth Revision [ICD-9] codes 296.2 and 296.3) and 2296 (9%) with dysthymic disorder (ICD-9 code 300.4) were identified. The current analysis was conducted from January 2015 to November 2015.
MAIN OUTCOMES AND MEASURES
Incident AMI (defined by discharge summary documentation, enzyme/electrocardiography evidence of AMI, inpatient ICD-9 code for AMI (410), or AMI as underlying cause of death [International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code 121]) between the enrollment date and December 31, 2009.
RESULTS
The mean (SD) age of those with MDD was 47.3 (7.9) years and for those without MDD was 48.2 (9.7) years. During 5.8 years of follow-up, 490 AMI events (1.9%) occurred. Baseline MDD was associated with incident AMI after adjusting for demographics (hazard ratio [HR], 1.31; 95% CI, 1.05–1.62), CVD risk factors (HR, 1.29; 95% CI, 1.04–1.60), and HIV-specific factors (HR, 1.30; 95% CI, 1.05–1.62). Further adjustment for hepatitis C, renal disease, substance abuse, and hemoglobin level (HR, 1.25; 95% CI, 1.00–1.56) and antidepressant use (HR, 1.12; 95% CI, 0.87–1.42) attenuated associations. Baseline dysthymic disorder was not associated with incident AMI.
CONCLUSIONS AND RELEVANCE
We report novel evidence that HIV-infected adults with MDD have a 30% increased risk for AMI than HIV-infected adults without MDD after adjustment for many potential confounders. Our findings raise the possibility that MDD may be independently associated with incident atherosclerotic CVD in the HIV-infected population
Depression and HIV Infection are Risk Factors for Incident Heart Failure Among Veterans: Veterans Aging Cohort Study.
Background: Both HIV and depression are associated with increased heart failure (HF) risk. Depression, a common comorbidity, may further increase the risk of HF among HIV+ adults. We assessed the association between HIV, depression and incident HF. Methods and Results: Veterans Aging Cohort Study (VACS) participants free from cardiovascular disease at baseline (N = 81,427; 26,908 HIV+, 54,51
Structural and functional characterization of endothelial microparticles released by cigarette smoke
Circulating endothelial microparticles (EMPs) are emerging as biomarkers of chronic obstructive pulmonary disease (COPD) in individuals exposed to cigarette smoke (CS), but their mechanism of release and function remain unknown. We assessed biochemical and functional characteristics of EMPs and circulating microparticles (cMPs) released by CS. CS exposure was sufficient to increase microparticle levels in plasma of humans and mice, and in supernatants of primary human lung microvascular endothelial cells. CS-released EMPs contained predominantly exosomes that were significantly enriched in let-7d, miR-191; miR-126; and miR125a, microRNAs that reciprocally decreased intracellular in CS-exposed endothelium. CS-released EMPs and cMPs were ceramide-rich and required the ceramide-synthesis enzyme acid sphingomyelinase (aSMase) for their release, an enzyme which was found to exhibit significantly higher activity in plasma of COPD patients or of CS-exposed mice. The ex vivo or in vivo engulfment of EMPs or cMPs by peripheral blood monocytes-derived macrophages was associated with significant inhibition of efferocytosis. Our results indicate that CS, via aSMase, releases circulating EMPs with distinct microRNA cargo and that EMPs affect the clearance of apoptotic cells by specialized macrophages. These targetable effects may be important in the pathogenesis of diseases linked to endothelial injury and inflammation in smokers
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