The Chlamydia trachomatis type III-secreted effector protein CteG induces centrosome amplification through interactions with centrin-2.

The centrosome is the main microtubule organizing center of the cell and is crucial for mitotic spindle assembly, chromosome segregation, and cell division. Centrosome duplication is tightly controlled, yet several pathogens, most notably oncogenic viruses, perturb this process leading to increased centrosome numbers. Infection by the obligate intracellular bacterium Chlamydia trachomatis (C.t.) correlates with blocked cytokinesis, supernumerary centrosomes, and multipolar spindles; however, the mechanisms behind how C.t. induces these cellular abnormalities remain largely unknown. Here we show that the secreted effector protein, CteG, binds to centrin-2 (CETN2), a key structural component of centrosomes and regulator of centriole duplication. Our data indicate that both CteG and CETN2 are necessary for infection-induced centrosome amplification, in a manner that requires the C-terminus of CteG. Strikingly, CteG is important for in vivo infection and growth in primary cervical cells but is dispensable for growth in immortalized cells, highlighting the importance of this effector protein to chlamydial infection. These findings begin to provide mechanistic insight into how C.t. induces cellular abnormalities during infection, but also indicate that obligate intracellular bacteria may contribute to cellular transformation events. Centrosome amplification mediated by CteG-CETN2 interactions may explain why chlamydial infection leads to an increased risk of cervical or ovarian cancer.

In Search of a Mechanistic Link between Chlamydia trachomatis-Induced Cellular Pathophysiology and Oncogenesis.

Centrosome duplication and cell cycle progression are essential cellular processes that must be tightly controlled to ensure cellular integrity. Despite their complex regulatory mechanisms, microbial pathogens have evolved sophisticated strategies to co-opt these processes to promote infection. While misregulation of these processes can greatly benefit the pathogen, the consequences to the host cell can be devastating. During infection, the obligate intracellular pathogen Chlamydia trachomatis induces gross cellular abnormalities, including supernumerary centrosomes, multipolar spindles, and defects in cytokinesis. While these observations were made over 15 years ago, identification of the bacterial factors responsible has been elusive due to the genetic intractability of Chlamydia. Recent advances in techniques of genetic manipulation now allows for the direct linking of bacterial virulence factors to manipulation of centrosome duplication and cell cycle progression. In this review, we discuss the impact, both immediate and downstream, of C. trachomatis infection on the host cell cycle regulatory apparatus and centrosome replication. We highlight links between C. trachomatis infection and cervical and ovarian cancers and speculate whether perturbations of the cell cycle and centrosome are sufficient to initiate cellular transformation. We also explore the biological mechanisms employed by Inc proteins and other secreted effector proteins implicated in the perturbation of these host cell pathways. Future work is needed to better understand the nuances of each effector's mechanism and their collective impact on Chlamydia's ability to induce host cellular abnormalities.

Identification and Preliminary Characterization of Novel Type III Secreted Effector Proteins in Chlamydia trachomatis.

Chlamydia trachomatis is an obligate intracellular pathogen that replicates in a host-derived vacuole termed the inclusion. Central to pathogenesis is a type III secretion system that translocates effector proteins into the host cell, which are predicted to play major roles in host cell invasion, nutrient acquisition, and immune evasion. However, until recently, the genetic intractability of C. trachomatis hindered identification and characterization of these important virulence factors. Here, we sought to expand the repertoire of identified effector proteins and confirm they are secreted during C. trachomatis infection. Utilizing bioinformatics, we identified 18 candidate substrates that had not been previously assessed for secretion, of which we show four to be secreted, using Yersinia pseudotuberculosis as a surrogate host. Using adenylate cyclase (CyaA), BlaM, and glycogen synthase kinase (GSK) secretion assays, we identified nine novel substrates that were secreted in at least one assay. Interestingly, only three of the substrates, shown to be translocated by C. trachomatis, were similarly secreted by Y. pseudotuberculosis. Using large-scale screens to determine subcellular localization and identify effectors that perturb crucial host cell processes, we identified one novel substrate, CT392, that is toxic when heterologously expressed in Saccharomyces cerevisiae. Toxicity required both the N- and C-terminal regions of the protein. Additionally, we show that these newly described substrates traffic to distinct host cell compartments, including vesicles and the cytoplasm. Collectively, our study expands the known repertoire of C. trachomatis secreted factors and highlights the importance of testing for secretion in the native host using multiple secretion assays when possible.

The Chlamydia trachomatis secreted effector TmeA hijacks the N-WASP-ARP2/3 actin remodeling axis to facilitate cellular invasion.

As an obligate intracellular pathogen, host cell invasion is paramount to Chlamydia trachomatis proliferation. While the mechanistic underpinnings of this essential process remain ill-defined, it is predicted to involve delivery of prepackaged effector proteins into the host cell that trigger plasma membrane remodeling and cytoskeletal reorganization. The secreted effector proteins TmeA and TarP, have risen to prominence as putative key regulators of cellular invasion and bacterial pathogenesis. Although several studies have begun to unravel molecular details underlying the putative function of TarP, the physiological function of TmeA during host cell invasion is unknown. Here, we show that TmeA employs molecular mimicry to bind to the GTPase binding domain of N-WASP, which results in recruitment of the actin branching ARP2/3 complex to the site of chlamydial entry. Electron microscopy revealed that TmeA mutants are deficient in filopodia capture, suggesting that TmeA/N-WASP interactions ultimately modulate host cell plasma membrane remodeling events necessary for chlamydial entry. Importantly, while both TmeA and TarP are necessary for effective host cell invasion, we show that these effectors target distinct pathways that ultimately converge on activation of the ARP2/3 complex. In line with this observation, we show that a double mutant suffers from a severe entry defect nearly identical to that observed when ARP3 is chemically inhibited or knocked down. Collectively, our study highlights both TmeA and TarP as essential regulators of chlamydial invasion that modulate the ARP2/3 complex through distinct signaling platforms, resulting in plasma membrane remodeling events that are essential for pathogen uptake.

Social network isolation mediates associations between risky symptoms and substance use in the high school transition.

The current study examined whether social status and social integration, two related but distinct indicators of an adolescent's standing within a peer network, mediate the association between risky symptoms (depressive symptoms and deviant behavior) and substance use across adolescence. The sample of 6,776 adolescents participated in up to seven waves of data collection spanning 6th to 12th grades. Scores indexing social status and integration were derived from a social network analysis of six schools and subsequent psychometric modeling. Results of latent growth models showed that social integration and status mediated the relation between risky symptoms and substance use and that risky symptoms mediated the relation between social standing and substance use during the high school transition. Before this transition, pathways involving deviant behavior led to high social integration and status and in turn to substance use. After this transition, both deviant behavior and depressive symptoms led to low social integration and status and in turn greater substance use. These findings suggest that the high school transition is a risky time for substance use related to the interplay of increases in depressive symptoms and deviant behavior on the one hand and decreases in social status and integration on the other.

A Latent Variable Approach to Measuring Social Dynamics in Adolescence.

In the study of adolescent health, it is useful to derive indices of social dynamics from sociometric data, and to use these indices as predictors of health risk behaviors. In this manuscript, we introduce a flexible latent variable model as a novel way of obtaining estimates of social integration and social status from school-based sociometric data. Such scores provide the flexibility of a regression-based approach while accounting for measurement error in sociometric indicators. We demonstrate the utility of these factor scores in testing complex hypotheses through a combination of structural equation modeling and survival models, showing that deviance mediates the relationship between social status and smoking onset hazard at the transition to high school.

Chemokine Receptor 7 Is Essential for Coxiella burnetii Whole-Cell Vaccine-Induced Cellular Immunity but Dispensable for Vaccine-Mediated Protective Immunity.

BACKGROUND: Protective immunity against Coxiella burnetii infection is conferred by vaccination with virulent (PI-WCV), but not avirulent (PII-WCV) whole-cell inactivated bacterium. The only well-characterized antigenic difference between virulent and avirulent C. burnetii is they have smooth and rough lipopolysaccharide (LPS), respectively. METHODS: Mice were vaccinated with PI-WCV and PII-WCV. Humoral and cellular responses were evaluated using protein chip microarrays and ELISpots, respectively. Dendritic cell (DC) maturation after stimulation with PI-WVC and PII-WVC was evaluated using flow cytometry. Vaccine-challenge studies were performed to validate the importance of the receptor CCR7. RESULTS: Other than specific antibody response to PI-LPS, similar antibody profiles were observed but IgG titers were significantly higher after vaccination with PI-WCV. Furthermore, higher frequency of antigen-specific CD4+ T cells was detected in mice immunized with PI-WCV. PI-WCV-stimulated DCs displayed significantly higher levels of CCR7 and migratory ability to secondary lymphoid organs. Challenge-protection studies in wild-type and CCR7-deficient mice confirmed that CCR7 is critical for PI-WCV-induced cellular immunity. CONCLUSIONS: PI-WVC stimulates protective immunity to C. burnetii in mice through stimulation of migratory behavior in DCs for protective cellular immunity. Additionally, the humoral immune response to LPS is an important component of protective immunity.

Mitochondrial Respiration Is Impaired during Late-Stage Hamster Prion Infection.

Mitochondria are crucial to proper neuronal function and overall brain health. Mitochondrial dysfunction within the brain has been observed in many neurodegenerative diseases, including prion disease. Several markers of decreased mitochondrial activity during prion infection have been reported, yet the bioenergetic respiratory status of mitochondria from prion-infected animals is unknown. Here we show that clinically ill transgenic mice overexpressing hamster prion protein (Tg7) infected with the hamster prion strain 263K suffer from a severe deficit in mitochondrial oxygen consumption in response to the respiratory complex II substrate succinate. Characterization of the mitochondrial proteome of purified brain mitochondria from infected and uninfected Tg7 mice showed significant differences in the relative abundance of key mitochondrial electron transport proteins in 263K-infected animals relative to that in controls. Our results suggest that at clinical stages of prion infection, dysregulation of respiratory chain proteins may lead to impairment of mitochondrial respiration in the brain.IMPORTANCE Mitochondrial dysfunction is present in most major neurodegenerative diseases, and some studies have suggested that mitochondrial processes may be altered during prion disease. Here we show that hamster prion-infected transgenic mice overexpressing the hamster prion protein (Tg7 mice) suffer from mitochondrial respiratory deficits. Tg7 mice infected with the 263K hamster prion strain have little or no signs of mitochondrial dysfunction at the disease midpoint but suffer from a severe deficit in mitochondrial respiration at the clinical phase of disease. A proteomic analysis of the isolated brain mitochondria from clinically affected animals showed that several proteins involved in electron transport, mitochondrial dynamics, and mitochondrial protein synthesis were dysregulated. These results suggest that mitochondrial dysfunction, possibly exacerbated by prion protein overexpression, occurs at late stages during 263K prion disease and that this dysfunction may be the result of dysregulation of mitochondrial proteins.

Profiles of internalizing and externalizing symptoms associated with bullying victimization.

This study identified profiles of internalizing (anxiety and depression) and externalizing (delinquency and violence against peers) symptoms among bullying victims and examined associations between bullying victimization characteristics and profile membership. The sample consisted of 1196 bullying victims in grades 8-10 (Mage = 14.4, SD = 1.01) who participated in The Context Study in three North Carolina counties in Fall 2003. Five profiles were identified using latent profile analysis: an asymptomatic profile and four profiles capturing combinations of internalizing and externalizing symptoms. Associations between bullying characteristics and membership in symptom profiles were tested using multinomial logistic regression. More frequent victimization increased odds of membership in the two high internalizing profiles compared to the asymptomatic profile. Across all multinomial logistic regression models, when the high internalizing, high externalizing profile was the reference category, adolescents who received any type of bullying (direct, indirect, or dual) were more likely to be in this category than any others.

Depressive Symptomology as a Moderator of Friend Selection and Influence on Substance Use Involvement: Estimates from Grades 6 to 12 in Six Longitudinal School-Based Social Networks.

Although the contributions of friend selection and friend influence to adolescent homophily on substance use behaviors has been of enduring research interest, moderators of these processes have received relatively little research attention. Identification of factors that dampen or amplify selection and influence on substance use behaviors is important for informing prevention efforts. Whereas prior research has examined adolescent drinking, smoking, and marijuana use, the current study examined whether friend selection and friend influence operated on substance use involvement, an indicator of problematic use, and whether depressive symptomology moderated these processes. In addition, it examined whether these relationships varied from grade 6 to 12. The study used a cohort-sequential design in which three cohorts of youth (first surveyed in grades, 6, 7, and 8) in six school-based longitudinal social networks were surveyed up to seven times, yielding N = 6817 adolescents (49% female). Stochastic actor-oriented models were applied to test hypothesized relationships in the six networks, then results were synthesized in a meta-analysis. Depressive symptoms did not moderate selection or influence on substance use involvement at any grade level, but indirectly contributed to diffusion of substance use involvement through school networks via patterns of network ties. Research is needed on contextual factors, particularly in schools, that might account for when, if at all, depressive symptoms condition friend selection and influence on substance use.

Cyberbullying in Children and Youth: Implications for Health and Clinical Practice.

We review the recent literature on cyberbullying and its effects on victimised youth, identifying key points. We conclude that cyberbullying, while following many of the underlying dynamics of more traditional forms of bullying, features some unique qualities that can both magnify the damage caused and make it more difficult to detect. These features include the pervasive, never-ending nature of cyberbullying and the ability to quickly reach large audiences. The potential for anonymity and the related distance afforded by screens and devices compared to in-person interaction allow the cruelty of cyberbullying to go unchecked. Despite the perceived anonymity of cyberbullying, cyberbullying can be perpetrated by friends, who often have intimate knowledge about the victimised youth that can be devastating when made public. Given the difficulty schools face in preventing or even detecting cyberbullying, health care providers are an important ally, due to their knowledge of the youth, the sense of trust they bring to youth, and their independence from the school setting. We conclude by calling for routine screening of bullying by health care providers who deal with paediatric populations.

Relative Abundance of apoE and Aß1-42 Associated with Abnormal Prion Protein Differs between Creutzfeldt-Jakob Disease Subtypes.

Aggregated and protease-resistant mammalian prion protein (PrPSc) is the primary protein component of infectious prions. Enriched PrPSc preparations are often used to study the mechanisms that underly prion disease. However, most enrichment procedures are relatively nonspecific and tend to yield significant amounts of non-PrPSc components including various proteins that could confound functional and structural studies. It is thus important to identify these proteins and assess their potential relevance to prion pathogenesis. Following proteinase K treatment and phosphotungstic acid precipitation of brain homogenate, we have used mass spectrometry to analyze the protein content of PrPSc isolated from prion-infected mice, multiple cases of sporadic Creutzfeldt-Jakob disease (sCJD), and human growth hormone associated cases of iatrogenic CJD (iCJD). Creatine kinase was the primary protein contaminant in all PrPSc samples, while many of the other proteins identified were also found in non-CJD controls, which suggests that they are not CJD specific. Interestingly, the Alzheimer's disease associated peptide amyloid ß 1-42 (Aß1-42) was identified in the majority of the sCJD cases as well as non-CJD age-matched controls, while apoliprotein E was found in greater abundance in the sCJD cases. By contrast, while some of the iCJD cases showed evidence of higher molecular weight Aß oligomers, monomeric Aß1-42 peptide was not detected by immunoblot, and only one case had significant levels of apolipoprotein E. Our data are consistent with the age-associated deposition of Aß1-42 in older sporadic CJD and non-CJD patients and suggest that both apolipoprotein E and Aß1-42 abundance can differ depending upon the type of CJD.

The Type IV Secretion System Effector Protein CirA Stimulates the GTPase Activity of RhoA and Is Required for Virulence in a Mouse Model of Coxiella burnetii Infection.

Coxiella burnetii, the etiological agent of Q fever in humans, is an intracellular pathogen that replicates in an acidified parasitophorous vacuole derived from host lysosomes. Generation of this replicative compartment requires effectors delivered into the host cell by the Dot/Icm type IVb secretion system. Several effectors crucial for C. burnetii intracellular replication have been identified, but the host pathways coopted by these essential effectors are poorly defined, and very little is known about how spacious vacuoles are formed and maintained. Here we demonstrate that the essential type IVb effector, CirA, stimulates GTPase activity of RhoA. Overexpression of CirA in mammalian cells results in cell rounding and stress fiber disruption, a phenotype that is rescued by overexpression of wild-type or constitutively active RhoA. Unlike other effector proteins that subvert Rho GTPases to modulate uptake, CirA is the first effector identified that is dispensable for uptake and instead recruits Rho GTPase to promote biogenesis of the bacterial vacuole. Collectively our results highlight the importance of CirA in coopting host Rho GTPases for establishment of Coxiella burnetii infection and virulence in mammalian cell culture and mouse models of infection.

Examining explanations for the link between bullying perpetration and physical dating violence perpetration: Do they vary by bullying victimization?

This short-term longitudinal study examined whether the association between bullying perpetration and later physical dating violence perpetration and mediators of that association (via anger, depression, anxiety, and social status), varied depending on level of bullying victimization. Differences have been noted between those who bully but are not victims of bullying, and those who are both bullies and victims. These differences may influence dating violence risk and the explanations for why bullying leads to dating violence. Data were from dating adolescents in three rural counties who completed self-administered questionnaires in the fall semester of grades 8-10 and again in the spring semester. The sample (N = 2,414) was 44.08% male and 61.31% white. Bullying perpetration in the fall semester predicted physical dating violence perpetration in the spring semester when there was no bullying victimization, but not when there was any bullying victimization. Bullying perpetration was positively associated with anger at all levels of bullying victimization and with social status when there was no or low amounts of victimization; it was negatively associated with social status at high levels of victimization. Bullying victimization was positively associated with anger, depression, and anxiety at all levels of bullying perpetration. Anger mediated the association between bullying perpetration and dating violence, regardless of level of victimization; depression, anxiety, and social status did not mediate the association at any level of bullying victimization. The findings have implications for dating violence prevention efforts and for future research on the link between bullying and dating violence.

Mitochondrial glycerol-3-phosphate acyltransferase-1 is essential for murine CD4(+) T cell metabolic activation.

Glycerol-3-phosphate acyltransferase-1 is the first rate limiting step in de novo glycerophospholipid synthesis. We have previously demonstrated that GPAT-1 deletion can significantly alter T cell function resulting in a T cell phenotype similar to that seen in aging. Recent studies have suggested that changes in the metabolic profile of T cells are responsible for defining specific effector functions and T cell subsets. Therefore, we determined whether T cell dysfunction in GPAT-1 (-/-) CD4(+) T cells could be explained by changes in cellular metabolism. We show here for the first time that GPAT-1 (-/-) CD4(+) T cells exhibit several key metabolic defects. Striking decreases in both the oxygen consumption rate (OCR) and the extracellular acidification rate (ECAR) were observed in GPAT-1 (-/-) CD4(+) T cells following CD3/CD28 stimulation indicating an inherent cellular defect in energy production. In addition, the spare respiratory capacity (SRC) of GPAT-1 (-/-) CD4+ T cells, a key indicator of their ability to cope with mitochondrial stress was significantly decreased. We also observed a significant reduction in mitochondrial membrane potential in GPAT-1 (-/-) CD4(+) T cells compared to their WT counterparts, indicating that GPAT-1 deficiency results in altered or dysfunctional mitochondria. These data demonstrate that deletion of GPAT-1 can dramatically alter total cellular metabolism under conditions of increased energy demand. Furthermore, altered metabolic response following stimulation may be the defining mechanism underlying T cell dysfunction in GPAT-1 (-/-) CD4(+) T cells. Taken together, these results indicate that GPAT-1 is essential for the response to the increased metabolic demands associated with T cell activation.

Age-related increase in IL-17 activates pro-inflammatory signaling in prostate cells.

BACKGROUND: A close relationship between aging, inflammation, and prostate cancer is widely accepted. Aging is accompanied by a progressive increase in pro-inflammatory cytokines, including interleukin 17 (IL-17), a key pro-inflammatory cytokine that becomes dysregulated with age. However, the contribution of IL-17 to age-related prostate tumorigenesis remains unclear. The aim of this study was to investigate the role of age-related IL-17 dysregulation in prostate tumorigenesis. METHODS: Serum and splenic T-lymphocytes from young GPAT-1 knock-out aging-mimic T cell mice as well as young and aged wild-type mice were collected. shRNA was used to knock down the IL-17 receptor in LNCaP prostate cancer cells and RWPE-1 non-transformed prostate epithelial cells, which were then exposed to the mouse sera or conditioned media from stimulated T-lymphocytes. NF-κB activation, NF-κB target gene expression, and cell proliferation were all measured in these cells by luciferase assay, qPCR, Western blot analysis, and MTT assay, respectively. RESULTS: T-lymphocyte-secreted IL-17 from aging-mimic mice induced NF-κB activity and target gene expression in LNCaP and RWPE-1 cells. It also promoted proliferation of these cells. CONCLUSION: Aging-mimic T cell mice produce increased levels of IL-17, which stimulates the pro-inflammatory NF-κB pathway in prostate epithelial cells. NF-κB increases inflammation, carcinogenesis and metastatic potential in the prostate. These findings provide evidence that the dysregulation of cytokine production seen in aged T cells may directly contribute to the increased risk for prostate cancer in the elderly.

Proteomics applications in prion biology and structure.

Prion diseases are a heterogeneous class of fatal neurodegenerative disorders associated with misfolding of host cellular prion protein (PrP(C)) into a pathological isoform, termed PrP(Sc). Prion diseases affect various mammals, including humans, and effective treatments are not available. Prion diseases are distinguished from other protein misfolding disorders - such as Alzheimer's or Parkinson's disease - in that they are infectious. Prion diseases occur sporadically without any known exposure to infected material, and hereditary cases resulting from rare mutations in the prion protein have also been documented. The mechanistic underpinnings of prion and other neurodegenerative disorders remain poorly understood. Various proteomics techniques have been instrumental in early PrP(Sc) detection, biomarker discovery, elucidation of PrP(Sc) structure and mapping of biochemical pathways affected by pathogenesis. Moving forward, proteomics approaches will likely become more integrated into the clinical and research settings for the rapid diagnosis and characterization of prion pathogenesis.

The PINK1/Parkin pathway of mitophagy exerts a protective effect during prion disease.

The PINK1/Parkin pathway of mitophagy has been implicated in the pathogenesis of Parkinson's disease. In prion diseases, a transmissible neurodegenerative disease caused by the misfolded and infectious prion protein (PrPSc), expression of both PINK1 and Parkin are elevated, suggesting that PINK1/Parkin mediated mitophagy may also play a role in prion pathogenesis. Using mice in which expression of either PINK1 (PINK1KO) or Parkin (ParkinKO) has been ablated, we analyzed the potential role of PINK1 and Parkin in prion pathogenesis. Prion infected PINK1KO and ParkinKO mice succumbed to disease more rapidly (153 and 150 days, respectively) than wild-type control C57Bl/6 mice (161 days). Faster incubation times in PINK1KO and ParkinKO mice did not correlate with altered prion pathology in the brain, altered expression of proteins associated with mitochondrial dynamics, or prion-related changes in mitochondrial respiration. However, the expression level of mitochondrial respiration Complex I, a major site for the formation of reactive oxygen species (ROS), was higher in prion infected PINK1KO and ParkinKO mice when compared to prion infected control mice. Our results demonstrate a protective role for PINK1/Parkin mitophagy during prion disease, likely by helping to minimize ROS formation via Complex I, leading to slower prion disease progression.

Global mapping of the Chlamydia trachomatis conventional secreted effector - host interactome reveals CebN interacts with nucleoporins and Rae1 to impede STAT1 nuclear translocation.

Chlamydia trachomatis (C.t.), the leading cause of bacterial sexually transmitted infections, employs a type III secretion system (T3SS) to translocate two classes of effectors, inclusion membrane proteins and conventional T3SS (cT3SS) effectors, into the host cell to counter host defense mechanisms. Here we employed three assays to directly evaluate secretion during infection, validating secretion for 23 cT3SS effectors. As bioinformatic analyses have been largely unrevealing, we conducted affinity purification-mass spectrometry to identify host targets and gain insights into the functions of these effectors, identifying high confidence interacting partners for 21 cT3SS effectors. We demonstrate that CebN localizes to the nuclear envelope in infected and bystander cells where it interacts with multiple nucleoporins and Rae1, blocking STAT1 nuclear import following IFN-γ stimulation. By building a cT3SS effector-host interactome, we have identified novel pathways that are targeted during bacterial infection and have begun to address how C.t. effectors combat cell autonomous immunity.

Age-related alterations in T-lymphocytes modulate key pathways in prostate tumorigenesis.

BACKGROUND: The primary risk for prostate cancer is aging, often associated with inflammation. Evidence implicates progressive age-related immune dysfunction with increased prostate cancer incidence and mortality. The aged T-cell response is characterized by increased production of pro-inflammatory cytokines, which could significantly contribute to prostate tumorigenesis through induction of key inflammation-mediated pro-survival factors. METHODS: T-cell function of the young (<6 month-old) glycerol-3-phosphate acyltransferase-1 (GPAT-1) knock-out mouse mimics many of the hallmarks observed in an aged (>22-month-old) mouse. Serum and splenic T-lymphocytes from young GPAT-1(-/-) (6 months) and aged wild type (22 months) mice were collected for in vitro studies, including a cytokine immunoarray for serum cytokine levels, luciferase assays for NF-κB activation and Western blot analyses for protein expression. RESULTS: The T-cell cytokine profile of the GPAT-1(-/-) mice mirrored that observed in aged wild type mice, including higher expression levels of IL-17. Serum- and T-cell-derived factors induced NF-κB activity in normal, non-transformed and prostate cancer epithelial cells, correlating with re-localization of NF-κB and increased protein expression of downstream targets of NF-κB. CONCLUSION: The aging and aging-mimic mice produced circulating factors that induce pro-inflammatory pathways in prostate cells, most notably NF-κB. These findings provide evidence that an aged T-cell may directly contribute to the increased risk for prostate cancer in the elderly and establish that the GPAT-1(-/-) model, which mimics many of the characteristics of an aged immune system, is a viable tool for investigating this novel area of cancer risk.