Correlations Between Relative Prevalence of Celiac Disease and Sociodemographic Variables in the United States.

INTRODUCTION: We evaluated the associations between celiac disease (CD) prevalence and regional sociodemographic variables in the United States. METHODS: The outcome was CD relative prevalence, defined as number of patients with CD among those in a Medicare registry per 3-digit ZIP code. Linear regression models assessed associations between relative prevalence of CD and sociodemographic variables. RESULTS: CD relative prevalence was positively correlated with median income, urban area, and proximity to a CD specialty center and negatively correlated with Black race, Latino/Hispanic ethnicity, and median social deprivation index score ( P < 0.01, all). DISCUSSION: CD relative prevalence is associated with indicators of economic advantage.

Statistical shape modelling provides a responsive measure of morphological change in knee osteoarthritis over 12 months.

OBJECTIVES: Responsive biomarkers are needed to assess the progression of OA and their lack has hampered previous clinical trials. Statistical shape modelling (SSM) from radiographic images identifies those at greatest risk of fast-progression or joint replacement, but its sensitivity to change has not previously been measured. This study evaluates the responsiveness of SSM in knee OA in a 12-month observational study. METHODS: A total of 109 people were recruited who had undergone knee radiographs in the previous 12 months, and were grouped based on severity of radiographic OA (Kellgren-Lawrence grading). An SSM was built from three dual-energy X-ray absorptiometry scans at 6-month intervals. Change-over-time and OA were assessed using generalized estimating equations, standardized response means (SRM) and reliable change indices. RESULTS: Mode 1 showed typical features of radiographic OA and had a strong link with Kellgren-Lawrence grading but did not change significantly during the study. Mode 3 showed asymmetrical changes consistent with medial cartilage loss, osteophytes and joint malalignment, and was responsive to change, with a 12-month SRM of 0.63. The greatest change was observed in the moderate radiographic OA group (SRM 0.92) compared with the controls (SRM 0.21), and the reliable change index identified 14% of this group whose progression was clinically significant. CONCLUSION: Shape changes linked the progression of osteophytosis with increasing malalignment within the joint. Modelling of the whole joint enabled quantification of change beyond the point where bone-to-bone contact has been made. The knee SSM is, therefore, a responsive biomarker for radiographic change in knees over 12 months.

Vitamin D Levels and SARS-CoV-2 Infection among Medically Underserved Populations in the Minority and Rural Coronavirus Insights Study.

BACKGROUND: Extant literature presents contradictory findings on the role of vitamin D on SARS-CoV-2 infection. Our study included an examination of the relationship between vitamin D levels and SARS-CoV-2 infection among the Minority and Rural Coronavirus Insights Study (MRCIS) cohort, a diverse population of medically underserved persons presenting at five Federally qualified health centers in the United States. METHODS: We conducted a descriptive analysis to explore the relationship between vitamin D levels and SARS-CoV-2 infection among medically underserved participants. A combined molecular and serologic assessment was used to determine the prevalence of SARS-CoV-2 infection. Vitamin D was examined as both a categorical (vitamin D status: deficient, insufficient, optimal) and continuous (vitamin D level) variable. Chi-squared testing, polynomial regression models, and logistic regression models were used to assess the relationship between vitamin D and SARS-CoV-2 infection. RESULTS: The overall SARS-CoV-2 infection rate among participants was 25.9%. Most participants were either vitamin D deficient (46.5%) or insufficient (29.7%), and 23.8% had an optimal level. Vitamin D status was significantly associated with key SARS-CoV-2 infection risk factors. As mean vitamin D levels increased, the proportion of participants with SARS-CoV-2 infection decreased. For every 10 ng/mL increase in vitamin D levels the odds of SARS-CoV-2 infection decreased by 12% when adjusting for race/ethnicity and age (main effect model). Participants who identified as Hispanic/Latino or Black non-Hispanic had approximately two times increased odds of SARS-CoV-2 infection when adjusting for age and vitamin D levels compared to white non-Hispanics. However, when additional factors were added to the main effect model, the relationship between vitamin D levels and SARS-CoV-2 infection did not remain significant. CONCLUSION: Vitamin D levels were associated with an increased risk of SARS-CoV-2 infection. Hispanic/Latino and Black, non-Hispanic compared to White, non-Hispanic participants were at increased odds for infection, after adjusting for race/ethnicity and age.

Predicting OA progression to total hip replacement: can we do better than risk factors alone using active shape modelling as an imaging biomarker?

OBJECTIVE: Previously, active shape modelling (ASM) of the proximal femur was shown to identify those individuals at highest risk of developing radiographic OA. Here we determine whether ASM predicts the need for total hip replacement (THR) independent of Kellgren-Lawrence grade (KLG) and other known risk factors. METHODS: A retrospective cohort study of 141 subjects consulting primary care with new hip pain was conducted. Pelvic radiographs taken on recruitment were assessed for KLG, centre-edge angle, acetabular depth and femoral head migration. Clinical factors (duration of pain, use of a stick and physical function) were collected by self-completed questionnaires. ASM differences between shape mode scores at baseline for individuals who underwent THR during the 5-year follow-up (n = 27) and those whose OA did not progress radiographically (n = 75) were compared. RESULTS: A 1 s.d. reduction in baseline ASM mode 2 score was associated with an 81% reduction in odds of THR (OR = 0.19, 95% CI 0.52, 0.70) after adjustment for KLG, radiographic and clinical factors. A similar reduction in odds of THR was associated with a 1 s.d. reduction in mode 3 (OR = 0.45, 95% CI 0.28, 0.71) and a 1 s.d. increase in mode 4 score (OR = 2.8, 95% CI 1.7, 4.7), although these associations were no longer significant after adjustment for KLG and clinical factors. CONCLUSION: ASM of the hip joint is a reliable early biomarker of radiographic OA severity, which can improve the ability to identify patients at higher risk of rapid progression and poor outcome even when KLG and clinical risk factors are taken into account.

The Use of Near-Infrared Light-Emitting Fluorescent Nanodiamond Particles to Detect Ebola Virus Glycoprotein: Technology Development and Proof of Principle.

BACKGROUND: There is a dire need for rapid diagnostic tests of high sensitivity, efficiency, and point-of-test reporting capability to mitigate lethal viral epidemic outbreaks. PURPOSE: To develop a new operating system within the lateral flow assay (LFA) format for Ebola virus (EBOV), based on fluorescent nanodiamond particles (FNDP) nitrogen vacancy (NV) emitting near-infrared (NIR) light. Specifically, we aimed to detail technical issues and the feasibility of mobilizing FNDP-NV on nitrocellulose membranes (NCM) and capturing them at test and control lines. METHODS: FNDP-NV-200nm, 400nm or 800nm were linked to anti-EBOV glycoprotein (GP) monoclonal antibodies (mAb) and tested for LFA performance by monitoring NIR emissions using an in vivo imaging system or optoelectronic device (OED). Anti-EBOV recombinant glycoprotein (GP) humanized mAb c13C6 was linked to FNDP-NV-200nm for the mobile phase; and a second anti-GP mouse mAb, 6D8, was printed on NCM at the test line. Goat anti-human IgG (GAH-IgG) served as a nonspecific antibody for conjugated FNDP-NV-200nm at the control line. RESULTS: FNDP-NV-200nm-c13C6 specifically and dose-dependently bound to recombinant EBOV GP in vitro and was effectively captured in a sandwich configuration at the test line by mAb 6D8. FNDP-NV-200nm-c13C6 was captured on the control line by GAH-IgG. The OED quantitative analysis of NIR (obtained in less than 1 minute) was further validated by an in vivo imaging system. CONCLUSION: FNDP-NV-200nm performance as a reporter for EBOV GP rapid diagnostic tests suggests an opportunity to replace contemporary visual tests for EBOV GP and other highly lethal viral pathogens. Mobile, battery-operated OED adds portability, quantitative data, rapid data collection, and point-of-test reporting capability. Further development of FNDP-NV-200nm within a LFA format is justified.

Common effects of lithium and valproate on mitochondrial functions: protection against methamphetamine-induced mitochondrial damage.

Accumulating evidence suggests that mitochondrial dysfunction plays a critical role in the progression of a variety of neurodegenerative and psychiatric disorders. Thus, enhancing mitochondrial function could potentially help ameliorate the impairments of neural plasticity and cellular resilience associated with a variety of neuropsychiatric disorders. A series of studies was undertaken to investigate the effects of mood stabilizers on mitochondrial function, and against mitochondrially mediated neurotoxicity. We found that long-term treatment with lithium and valproate (VPA) enhanced cell respiration rate. Furthermore, chronic treatment with lithium or VPA enhanced mitochondrial function as determined by mitochondrial membrane potential, and mitochondrial oxidation in SH-SY5Y cells. In-vivo studies showed that long-term treatment with lithium or VPA protected against methamphetamine (Meth)-induced toxicity at the mitochondrial level. Furthermore, these agents prevented the Meth-induced reduction of mitochondrial cytochrome c, the mitochondrial anti-apoptotic Bcl-2/Bax ratio, and mitochondrial cytochrome oxidase (COX) activity. Oligoarray analysis demonstrated that the gene expression of several proteins related to the apoptotic pathway and mitochondrial functions were altered by Meth, and these changes were attenuated by treatment with lithium or VPA. One of the genes, Bcl-2, is a common target for lithium and VPA. Knock-down of Bcl-2 with specific Bcl-2 siRNA reduced the lithium- and VPA-induced increases in mitochondrial oxidation. These findings illustrate that lithium and VPA enhance mitochondrial function and protect against mitochondrially mediated toxicity. These agents may have potential clinical utility in the treatment of other diseases associated with impaired mitochondrial function, such as neurodegenerative diseases and schizophrenia.

Deficits in behavioral inhibition predict treatment engagement in prison inmates.

Many inmates do not respond favorably to standard treatments routinely offered in prison. Executive cognitive functioning and emotional regulation may play a key role in treatment responsivity. During intake into treatment, inmates (N = 224) were evaluated for executive functioning, emotional perception, stress reactivity (salivary cortisol), IQ, psychological and behavioral traits, prior drug use, child and family background, and criminal histories and institutional behavior. Outcome measures included program completion, treatment readiness, responsivity and gain, and the Novaco Reaction to Provocation Questionnaire. Relative deficits in behavioral inhibition significantly predicted treatment outcomes, more so than background, psychological, or behavioral variables, and other neurocognitive and emotional regulatory measures. Future replications of these results have potential to improve assessment and treatment of offenders who are otherwise intractable.

Mitochondria as key components of the stress response.

The exquisitely orchestrated adaptive response to stressors that challenge the homeostasis of the cell and organism involves important changes in mitochondrial function. A complex signaling network enables mitochondria to sense internal milieu or environmental changes and to adjust their bioenergetic, thermogenic, oxidative and/or apoptotic responses accordingly, aiming at re-establishment of homeostasis. Mitochondrial dysfunction is increasingly recognized as a key component in both acute and chronic allostatic states, although the extent of its role in the pathogenesis of such conditions remains controversial. Genetic and environmental factors that determine mitochondrial function might contribute to the significant variation of the stress response. Understanding the often reciprocal interplay between stress mediators and mitochondrial function is likely to help identify potential therapeutic targets for many stress and mitochondria-related pathologies.

Adenoviral gene transfer in bovine adrenomedullary and murine pheochromocytoma cells: potential clinical and therapeutic relevance.

Recombinant adenoviruses (rAd) have been widely used as gene transfer vectors both in the laboratory and in human clinical trials. In the present study, we investigated the effects of adenoviral-mediated gene transfer in primary bovine adrenal chromaffin cells (BACC) and a murine pheochromocytoma cell line (MPC). Cells were infected with one of three nonreplicating E1/E3-deleted (E1(-)/E3(-)) rAd vectors: Ad.GFP, expressing a green fluorescent protein (GFP); Ad.null, expressing no transgene; or Ad.C2.TK, expressing the herpes simplex virus-1 thymidine kinase gene (TK). Forty-eight hours after exposure to Ad.GFP, the percentage of GFP-expressing BACC ranged from 23.5-97% in a dose-dependent manner and similarly from 1.06-84.4% in the MPC, indicating that adrenomedullary cells are a potentially valuable target for adenoviral-mediated gene transfer. Ultrastructural analysis, however, revealed profound changes in the nucleus and mitochondria of cells infected with rAd. Furthermore, infection of BACC with Ad.null was accompanied by a time- and dose-dependent decrease in cell survival due to the vector alone. Specific whole-cell norepinephrine uptake was also decreased in a time- and dose-dependent fashion in BACC. Infection of MPC cells with the Ad.C2.TK vector sensitized them to the cytotoxic effect of the antiviral drug ganciclovir, in direct proportion to the fraction of cells infected with the virus. We conclude that rAd may alter the structural and functional integrity of adrenomedullary cells, potentially interfering with the normal stress response. At the same time, in light of their ability to effectively deliver and express genes in pheochromocytoma cells, they may be applicable to the gene therapy of adrenomedullary tumors.

Sustained low-grade pro-inflammatory state in unmedicated, remitted women with major depressive disorder as evidenced by elevated serum levels of the acute phase proteins C-reactive protein and serum amyloid A.

BACKGROUND: Major depressive disorder (MDD) shows increased coronary artery disease (CAD) risk of unknown mechanism(s). MDD is more common in women than men; CAD diagnosis can be difficult in women. Elevations of the inflammatory markers C-reactive protein (CRP) and serum amyloid A (SAA) predict increased CAD risk in populations; few data on these markers exist in MDD, particularly in remitted patients. METHODS: We measured fasting am serum CRP (high sensitivity, CRP(hs)) and SAA in 18 unmedicated, remitted women with MDD (mean age 41 +/- (SD)12, body mass index (BMI) 25.2 +/- 4.1 kg/m(2)) and 18 BMI-matched healthy control subjects (age 36 +/- 10, BMI 25.3 +/- 3.8 kg/m(2)) on 2 separate occasions, > or = 6 days apart. RESULTS: Repeat SAA and CRP(hs) measurements strongly correlated across study days (SAA: r = .83, p < .001; CRP(hs): r = .94, p < .001). Both SAA (5.30 +/- 3.39 vs. 2.84 +/- 1.87 mg/L, p < .005) and CRP(hs) (3.23 +/- 3.17 vs. 1.12 +/- 1.45 mg/L; p < .01) were significantly elevated in MDD women versus controls. CONCLUSIONS: Elevated SAA and CRP(hs) in remitted, unmedicated women with MDD indicate a pro-inflammatory state unrelated to current depressive symptoms or pharmacotherapy. These findings suggest that inflammatory mechanisms may in part underlie findings of increased CAD risk in MDD.

Third-generation human mitochondria-focused cDNA microarray and its bioinformatic tools for analysis of gene expression.

To facilitate profiling mitochondrial transcriptomes, we developed a third-generation human mitochondria-focused cDNA microarray (hMitChip3) and its bioinformatic tools. hMitChip3 consists of the 37 mitochondrial DNA-encoded genes, 1098 nuclear DNA-encoded and mitochondria-related genes, and 225 controls, each in triplicate. The bioinformatic tools included data analysis procedures and customized database for interpretation of results. The database associated 645 molecular functions with 946 hMitChip3 genes, 612 biological processes with 930 genes, 172 cellular components with 869 genes, 107 biological chemistry pathways with 476 genes, 23 reactome events with 227 genes, 320 genetic disorders with 237 genes, and 87 drugs targets with 55 genes. To test these tools, hMitChip3 was used to compare expression profiles between human melanoma cell lines UACC903 (rapidly dividing) and UACC903(+6) (slowly dividing). Our results demonstrated internal gene-set consistency (correlation R > or = 0.980 +/- 0.005) and interexperimental reproducibility (R > or = 0.931 +/- 0.013). Expression patterns of 16 genes, involved in DNA, RNA, or protein biosyntheses in mitochondrial and other organelles, were consistent with the proliferation rates of both cell lines, and the patterns of 6 tested genes were verified by quantitative reverse transcription PCR (RT-PCR). Thus, hMitChip3 and its bioinformatics software provide an integrated tool for profiling mitochondria-focused gene expression.

Mitochondrial localization of human recombinant adenovirus: from evolution to gene therapy.

Mitochondrial research has influenced concepts in anthropology, human physiology and pathophysiology. We present here direct evidence that human recombinant viruses can localize in mitochondria to disrupt their integrity. This finding, while opening new perspectives in viral gene therapy, may provide new insights into the pathogenesis, prevention and treatment of viral diseases. In addition, it may advance the current understanding of cell evolution.

Animal models of pheochromocytoma including NIH initial experience.

Mouse models have been used to study the mechanisms underlying the carcinogenesis of a wide variety of human cancer. A considerable number of mouse and rat models, used for the study of elementary tumorgenic mechanisms, were found to develop pheochromocytomas. Some of these models resemble hereditary syndrome-related pheochromocytoma in humans and some may serve as a new starting point for human pheochromocytoma research. Recently, we generated a model of catecholamine-producing metastatic pheochromocytoma in athymic nude mice using tail-vein injection of mouse pheochromocytoma cells (MPCs). This and alternative animal models of metastatic pheochromocytoma are promising avenues in preclinical studies to evaluate new therapeutic approaches for malignant pheochromocytoma.

Monoamine oxidase-A is a major target gene for glucocorticoids in human skeletal muscle cells.

Skeletal myopathy is a common complication of endogenous and exogenous glucocorticoid excess, yet its pathogenetic mechanisms remain unclear. There is accumulating evidence that mitochondrial dysfunction and oxidative stress are involved in this process. To explore the glucocorticoid-induced transcriptional adaptations that may affect mitochondrial function in skeletal muscle, we studied gene expression profiles in dexamethasone-treated primary human skeletal myocytes using a cDNA microarray, which contains 501 mitochondria-related genes. We found that monoamine oxidase A (MAO-A) was the most significantly up-regulated gene. MAO-A is the primary enzyme metabolizing catecholamines and dietary amines, and its role in skeletal muscle remains largely unexplored. Dexamethasone induced dose- and time-dependent increases of MAO-A gene and protein expression, while its effects on MAO-B were minimal. Both the glucocorticoid receptor (GR) and the Sp1 transcription factor were required for dexamethasone-induced MAO-A mRNA expression, as blockade of the GR with RU 486 or ablation of Sp1 binding with mithramycin abrogated MAO-A mRNA induction. The observed dexamethasone effect was biologically functional, as this steroid significantly increased MAO-mediated hydrogen peroxide production. We suggest that MAO-A-mediated oxidative stress can lead to cell damage, representing a novel pathogenetic mechanism for glucocorticoid-induced myopathy and a potential target for therapeutic intervention.

Intracrine modulation of gene expression by intracellular generation of active glucocorticoids.

Glucocorticoids (GC) by either up-regulating or down-regulating the expression of genes influence cellular processes in every tissue and organ of the body. The enzyme 11beta-hydroxysteroid dehydrogenase Type-1 (11beta-HSD-1) confers bioactivity upon the inactive GC cortisone (E) and prednisone (P) by converting them to cortisol (F) and prednisolone (L), respectively. We sought to investigate whether gene expression modulation by GC is under the regulation of an intracrine mechanism that determines the intracellular concentration of active GC. Human cell lines were transiently and stably co-transfected with an expression construct for 11beta-HSD-1 and a GC-responsive reporter gene and incubated with active and inactive GC. Whereas in cells that were not transfected with the expression construct for 11beta-HSD-1 inactive GC had no transcriptional activity, in both transiently and stably transfected cells E and P demonstrated a dose-dependent transcriptional activity. This transcriptional potency of both inactive GC was effectively abolished by carbenoxolone, an 11beta-HSD-1 inhibitor, and was directly related to the concentration of transfected 11beta-HSD-1. We conclude that gene expression modulation by GC is under a decisive influence of target cell 11beta-HSD-1 that modulates the intracellular concentration of active GC. The intracrine mechanism is an under-appreciated aspect of GC activity that could be a potential target for future therapies aimed at modulating GC effects at the cellular level.

Depression and osteoporosis in men: association or casual link?

The longer life expectancy of women than that of men and, therefore, the longer exposure to fracture risk has, at least partially, led to neglect of osteoporosis in men. Recently, unipolar depression, which is 2 times more frequent in women than in men, has been linked to osteoporosis. However, it is quite possible that this diagnosis may escape detection in men because of a different behavioral phenotype between the genders. A potential mechanism of bone loss in depression has been proposed, involving concurrent activation of the hypothalamo-pituitary-adrenal and sympatho-adrenal axes, suppression of the gonadal and somatotrophic axes, and high interleukin-6 and low leptin levels. We suggest that similar neurohormonal changes may cause osteoporosis in men.

The human glucocorticoid receptor (GR) isoform {beta} differentially suppresses GR{alpha}-induced transactivation stimulated by synthetic glucocorticoids.

The beta-isoform of human glucocorticoid receptor beta (hGRbeta) acts as a natural dominant negative inhibitor of hGRalpha-induced transactivation of glucocorticoid-responsive genes. We determined hGRbeta ability to suppress hGRalpha transactivation that was induced by commonly used synthetic glucocorticoids. HepG2/C3A cells were transiently cotransfected with GR cDNA and a glucocorticoid-responsive promoter, luciferase (MMTV-luc). Transfected cells were incubated for 16 h with glucocorticoid and luciferase. For each compound, a dose-response curve was constructed, and half-maximal effective concentrations and maximal transcriptional activities were compared. hGRbeta, at a 1:1 ratio to hGRalpha, differentially suppressed hGRalpha-induced maximal transcriptional activity stimulated by triamcinolone, dexamethasone, hydrocortisone, and betamethasone (by 96, 68, 62, and 49%, respectively) but not by methylprednisolone. The suppressive effect of hGRbeta on hGRalpha-induced transactivation was stronger at lower concentrations of all tested glucocorticoids, whereas it was blunted at higher concentrations. We conclude that the potency of the dominant negative effect of hGRbeta on hGRalpha-induced transactivation depends on both the type and the dose of the synthetic glucocorticoids in use. These results may provide helpful information concerning the selection of synthetic glucocorticoids for treatment of pathological conditions in which hGRbeta modulates the sensitivity of tissues to glucocorticoids.

Major depression is associated with significant diurnal elevations in plasma interleukin-6 levels, a shift of its circadian rhythm, and loss of physiological complexity in its secretion: clinical implications.

BACKGROUND: Major depressive disorder (MDD) is associated with increased risk for premature coronary heart disease and bone loss. Single time measurements of plasma IL-6, a good predictor of future risk for both cardiovascular disease and osteoporosis, revealed significant elevations in depressed patients. The objective of this study was to rigorously compare plasma IL-6 levels, measured over 24 h, in MDD patients and healthy controls. Given the activating role of IL-6 on the hypothalamic-pituitary-adrenal (HPA) axis, and the relevance of its dysregulation in MDD, we also analyzed the relations between IL-6 and cortisol levels. METHODS: We studied nine patients and nine controls, individually matched by gender, age (+/-5 yr), body mass index (+/-2 kg/m2), and menstrual cycle phase. Diagnosis of MDD was confirmed by structured clinical interview based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I diagnostic criteria. Self-reported mood ratings were assessed by multiple visual analog scales. The rhythmicity and complexity of IL-6 and cortisol secretion were tested by cosinor analyses, approximate entropy (ApEn) and cross-ApEn algorithms. RESULTS: MDD patients had significant mean IL-6 elevations from 1000-1200 h and at 1500 h (P ranging from <0.05 to <0.01) vs. controls. In addition, in MDD, the circadian rhythm of IL-6 was shifted by 12 h, and its physiological complexity was reduced, with no difference in the cross-ApEn of IL-6 and cortisol between the two groups, and significant time-lagged correlations only in the controls. IL-6 levels correlated significantly with mood ratings. CONCLUSIONS: We report profound morning elevations of plasma IL-6 and a reversal of its circadian rhythm in MDD patients, in the absence of hypercortisolism. These findings may be relevant to the increased risk for coronary heart disease and bone loss in MDD.

L-carnitine: A nutritional modulator of glucocorticoid receptor functions.

L-carnitine is an essential nutrient with a major role in cellular energy production. There is evidence that, at high doses, L-carnitine might mimic some of the biological activities of glucocorticoids, especially immunomodulation. To explore the molecular basis of this effect, we tested the influence of L-carnitine on glucocorticoid receptor-alpha (GRalpha) functions. Millimolar concentrations of L-carnitine, which were not cytotoxic in vitro, significantly reduced the whole cell binding of [3H]dexamethasone to GRalpha by decreasing the affinity of this receptor for its steroid ligand. At the same concentrations, L-carnitine was able to trigger nuclear translocation of green fluorescent protein (GFP)-fused human GRalpha and transactivate the glucocorticoid-responsive mouse mammary tumor virus (MMTV) and TAT3 promoters in a dose-dependent fashion. This effect was solely dependent on the presence of glucocorticoid-responsive elements on the promoter and on the expression of functional GRalpha by the cell. Finally, similarly to glucocorticoids, L-carnitine suppressed tumor necrosis factor-alpha (TNFalpha) and interleukin-12 release by human primary monocytes stimulated with lipopolysaccharide ex vivo. Both GRalpha transactivation and cytokine suppression by L-carnitine were abrogated by the GRalpha-antagonist RU 486. Taken together, our results suggest that pharmacological doses of L-carnitine can activate GRalpha and, through this mechanism, regulate glucocorticoid-responsive genes, potentially sharing some of the biological and therapeutic properties of glucocorticoids.

The glucocorticoid receptor and the orphan nuclear receptor chicken ovalbumin upstream promoter-transcription factor II interact with and mutually affect each other's transcriptional activities: implications for intermediary metabolism.

Glucocorticoids exert their metabolic effect via their intracellular receptor, the glucocorticoid receptor (GR). In a yeast two-hybrid screening, we found the chicken ovalbumin upstream promoter transcription factor II (COUP-TFII), an orphan nuclear receptor that plays important roles in glucose, cholesterol, and xenobiotic metabolism, as a partner of GR. In an in vitro glutathione-S-transferase pull-down assay, COUP-TFII interacted via its DNA-binding domain with the hinge regions of both GRalpha and its splicing variant GRbeta, whereas COUP-TFII formed a complex with GRalpha, but not with GRbeta, in an in vivo chromatin immunoprecipitation and a regular immunoprecipitation assay. Accordingly, GRalpha, but not GRbeta, enhanced COUP-TFII-induced transactivation of the simple COUP-TFII-responsive 7alpha-hydroxylase promoter through the transcriptional activity of its activation function-1 domain, whereas COUP-TFII repressed GRalpha-induced transactivation of the glucocorticoid-responsive promoter by attracting the silencing mediator for retinoid and thyroid hormone receptors. Importantly, mutual protein-protein interaction of GRalpha and COUP-TFII was necessary for glucocorticoid-induced enhancement of the promoter activity and the endogenous mRNA expression of the COUP-TFII-responsive phosphoenolpyruvate carboxykinase, the rate-limiting enzyme of hepatic gluconeogenesis. We suggest that COUP-TFII may participate in some of the metabolic effects of glucocorticoids through direct interactions with GRalpha. These interactions influence the transcription of both COUP-TFII- and GRalpha-responsive target genes, seem to be promoter specific, and can be in either a positive or negative direction.