CREB coactivators CRTC2 and CRTC3 modulate bone marrow hematopoiesis.

Populations of circulating immune cells are maintained in equilibrium through signals that enhance the retention or egress of hematopoietic stem cells (HSCs) from bone marrow (BM). Prostaglandin E2 (PGE2) stimulates HSC renewal and engraftment through, for example, induction of the cAMP pathway. Triggering of PGE2 receptors increases HSC survival in part via the PKA-mediated induction of the cAMP response element-binding protein (CREB) signaling pathway. PKA stimulates cellular gene expression by phosphorylating CREB at Ser133 and by promoting the dephosphorylation of the cAMP- responsive transcriptional coactivators (CRTCs). We show here that disruption of both CRTC2 and CRTC3 causes embryonic lethality, and that a single allele of either CRTC2 or CRTC3 is sufficient for viability. CRTC2 knockout mice that express one CRTC3 allele (CRTC2/3m mice) develop neutrophilia and splenomegaly in adulthood due to the up-regulation of granulocyte-colony stimulating factor (G-CSF); these effects are reversed following administration of neutralizing anti-G-CSF antiserum. Adoptive transfer of CRTC2/3m BM conferred the splenomegaly/neutrophilia phenotype in WT recipients. Targeted disruption of both CRTC2 and CRTC3 in stromal cells with a mesenchymal Prx1-Cre transgene also promoted this phenotype. Depletion of CRTC2/3 was found to decrease the expression of Suppressor of Cytokine Signaling 3 (SOCS3), leading to increases in STAT3 phosphorylation and to the induction of CEBPß, a key regulator of the G-CSF gene. As small molecule inhibition of JAK activity disrupted CEBPß induction and reduced G-CSF expression in CRTC2/3m stromal cells, our results demonstrate how cross-coupling between the CREB/CRTC and JAK/STAT pathways contributes to BM homeostasis.

CREB pathway links PGE2 signaling with macrophage polarization.

Obesity is thought to promote insulin resistance in part via activation of the innate immune system. Increases in proinflammatory cytokine production by M1 macrophages inhibit insulin signaling in white adipose tissue. In contrast, M2 macrophages have been found to enhance insulin sensitivity in part by reducing adipose tissue inflammation. The paracrine hormone prostaglandin E2 (PGE2) enhances M2 polarization in part through activation of the cAMP pathway, although the underlying mechanism is unclear. Here we show that PGE2 stimulates M2 polarization via the cyclic AMP-responsive element binding (CREB)-mediated induction of Krupple-like factor 4 (KLF4). Targeted disruption of CREB or the cAMP-regulated transcriptional coactivators 2 and 3 (CRTC2/3) in macrophages down-regulated M2 marker gene expression and promoted insulin resistance in the context of high-fat diet feeding. As re-expression of KLF4 rescued M2 marker gene expression in CREB-depleted cells, our results demonstrate the importance of the CREB/CRTC pathway in maintaining insulin sensitivity in white adipose tissue via its effects on the innate immune system.

A fasting inducible switch modulates gluconeogenesis via activator/coactivator exchange.

During early fasting, increases in skeletal muscle proteolysis liberate free amino acids for hepatic gluconeogenesis in response to pancreatic glucagon. Hepatic glucose output diminishes during the late protein-sparing phase of fasting, when ketone body production by the liver supplies compensatory fuel for glucose-dependent tissues. Glucagon stimulates the gluconeogenic program by triggering the dephosphorylation and nuclear translocation of the CREB regulated transcription coactivator 2 (CRTC2; also known as TORC2), while parallel decreases in insulin signalling augment gluconeogenic gene expression through the dephosphorylation and nuclear shuttling of forkhead box O1 (FOXO1). Here we show that a fasting-inducible switch, consisting of the histone acetyltransferase p300 and the nutrient-sensing deacetylase sirtuin 1 (SIRT1), maintains energy balance in mice through the sequential induction of CRTC2 and FOXO1. After glucagon induction, CRTC2 stimulated gluconeogenic gene expression by an association with p300, which we show here is also activated by dephosphorylation at Ser 89 during fasting. In turn, p300 increased hepatic CRTC2 activity by acetylating it at Lys 628, a site that also targets CRTC2 for degradation after its ubiquitination by the E3 ligase constitutive photomorphogenic protein (COP1). Glucagon effects were attenuated during late fasting, when CRTC2 was downregulated owing to SIRT1-mediated deacetylation and when FOXO1 supported expression of the gluconeogenic program. Disrupting SIRT1 activity, by liver-specific knockout of the Sirt1 gene or by administration of a SIRT1 antagonist, increased CRTC2 activity and glucose output, whereas exposure to SIRT1 agonists reduced them. In view of the reciprocal activation of FOXO1 and its coactivator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha, encoded by Ppargc1a) by SIRT1 activators, our results illustrate how the exchange of two gluconeogenic regulators during fasting maintains energy balance.

Insulin modulates gluconeogenesis by inhibition of the coactivator TORC2.

During feeding, increases in circulating pancreatic insulin inhibit hepatic glucose output through the activation of the Ser/Thr kinase AKT and subsequent phosphorylation of the forkhead transcription factor FOXO1 (refs 1-3). Under fasting conditions, FOXO1 increases gluconeogenic gene expression in concert with the cAMP responsive coactivator TORC2 (refs 4-8). In response to pancreatic glucagon, TORC2 is de-phosphorylated at Ser 171 and transported to the nucleus, in which it stimulates the gluconeogenic programme by binding to CREB. Here we show in mice that insulin inhibits gluconeogenic gene expression during re-feeding by promoting the phosphorylation and ubiquitin-dependent degradation of TORC2. Insulin disrupts TORC2 activity by induction of the Ser/Thr kinase SIK2, which we show here undergoes AKT2-mediated phosphorylation at Ser 358. Activated SIK2 in turn stimulated the Ser 171 phosphorylation and cytoplasmic translocation of TORC2. Phosphorylated TORC2 was degraded by the 26S proteasome during re-feeding through an association with COP1, a substrate receptor for an E3 ligase complex that promoted TORC2 ubiquitination at Lys 628. Because TORC2 protein levels and activity were increased in diabetes owing to a block in TORC2 phosphorylation, our results point to an important role for this pathway in the maintenance of glucose homeostasis.

Targeted disruption of the CREB coactivator Crtc2 increases insulin sensitivity.

Under fasting conditions, increases in circulating concentrations of pancreatic glucagon maintain glucose homeostasis through induction of gluconeogenic genes by the CREB coactivator CRTC2. Hepatic CRTC2 activity is elevated in obesity, although the extent to which this cofactor contributes to attendant increases in insulin resistance is unclear. Here we show that mice with a knockout of the CRTC2 gene have decreased circulating glucose concentrations during fasting, due to attenuation of the gluconeogenic program. CRTC2 was found to stimulate hepatic gene expression in part through an N-terminal CREB binding domain that enhanced CREB occupancy over relevant promoters in response to glucagon. Deletion of sequences encoding the CREB binding domain in CRTC2 (-/-) mice lowered circulating blood glucose concentrations and improved insulin sensitivity in the context of diet-induced obesity. Our results suggest that small molecules that attenuate the CREB-CRTC2 pathway may provide therapeutic benefit to individuals with type 2 diabetes.

Identification of the tyrosine phosphatase PTP-MEG2 as an antagonist of hepatic insulin signaling.

Insulin resistance is a primary defect in type 2 diabetes characterized by impaired peripheral glucose uptake and insufficient suppression of hepatic glucose output. Insulin signaling inhibits liver glucose production by inducing nuclear exclusion of the gluconeogenic transcription factor FOXO1 in an Akt-dependent manner. Through the concomitant application of genome-scale functional screening and quantitative image analysis, we have identified PTP-MEG2 as a modulator of insulin-dependent FOXO1 subcellular localization. Ectopic expression of PTP-MEG2 in cells inhibited insulin-induced phosphorylation of the insulin receptor, while RNAi-mediated reduction of PTP-MEG2 transcript levels enhanced insulin action. Additionally, adenoviral-mediated depletion of PTP-MEG2 in livers of diabetic (db/db) mice resulted in insulin sensitization and normalization of hyperglycemia. These data implicate PTP-MEG2 as a mediator of blood glucose homeostasis through antagonism of insulin signaling, and suggest that modulation of PTP-MEG2 activity may be an effective strategy in the treatment of type 2 diabetes.

PGC-1 promotes insulin resistance in liver through PPAR-alpha-dependent induction of TRB-3.

Insulin resistance is a major hallmark in the development of type 2 diabetes, which is characterized by an impaired ability of insulin to inhibit glucose output from the liver and to promote glucose uptake in muscle. The nuclear hormone receptor coactivator PGC-1 (peroxisome proliferator-activated (PPAR)-gamma coactivator-1) has been implicated in the onset of type 2 diabetes. Hepatic PGC-1 expression is elevated in mouse models of this disease, where it promotes constitutive activation of gluconeogenesis and fatty acid oxidation through its association with the nuclear hormone receptors HNF-4 and PPAR-alpha, respectively. Here we show that PGC-1-deficient mice, generated by adenoviral delivery of PGC-1 RNA interference (RNAi) to the liver, experience fasting hypoglycemia. Hepatic insulin sensitivity was enhanced in PGC-1-deficient mice, reflecting in part the reduced expression of the mammalian tribbles homolog TRB-3, a fasting-inducible inhibitor of the serine-threonine kinase Akt/PKB (ref. 6). We show here that, in the liver, TRB-3 is a target for PPAR-alpha. Knockdown of hepatic TRB-3 expression improved glucose tolerance, whereas hepatic overexpression of TRB-3 reversed the insulin-sensitive phenotype of PGC-1-deficient mice. These results indicate a link between nuclear hormone receptor and insulin signaling pathways, and suggest a potential role for TRB-3 inhibitors in the treatment of type 2 diabetes.

The CREB coactivator TORC2 is a key regulator of fasting glucose metabolism.

Glucose homeostasis is regulated systemically by hormones such as insulin and glucagon, and at the cellular level by energy status. Glucagon enhances glucose output from the liver during fasting by stimulating the transcription of gluconeogenic genes via the cyclic AMP-inducible factor CREB (CRE binding protein). When cellular ATP levels are low, however, the energy-sensing kinase AMPK inhibits hepatic gluconeogenesis through an unknown mechanism. Here we show that hormonal and energy-sensing pathways converge on the coactivator TORC2 (transducer of regulated CREB activity 2) to modulate glucose output. Sequestered in the cytoplasm under feeding conditions, TORC2 is dephosphorylated and transported to the nucleus where it enhances CREB-dependent transcription in response to fasting stimuli. Conversely, signals that activate AMPK attenuate the gluconeogenic programme by promoting TORC2 phosphorylation and blocking its nuclear accumulation. Individuals with type 2 diabetes often exhibit fasting hyperglycaemia due to elevated gluconeogenesis; compounds that enhance TORC2 phosphorylation may offer therapeutic benefits in this setting.

Improving the long-term care referral process: insights from patients and caregivers.

Large increases in the need for long-term care (LTC) services are expected as baby boomers age. Little has been published about patient and caregiver preferences for information about LTC. However, our qualitative research findings suggest that potential consumers may find it difficult to obtain accurate and timely information about LTC programs and services. In-person, semistructured interviews were conducted with 47 subjects, including patients (n = 25) within 90 days of their referral to a LTC placement (including NH, assisted living, home care, and community) and their caregivers (n = 22). Interview questions addressed the events that seemed to trigger their need for a LTC referral, the resources they used to become more informed about LTC options and the issues they confronted with the LTC referral process. Qualitative analyses identified a number of patient and informal caregiver-reported barriers to making decisions about LTC services, including insufficient information about LTC programs and community resources, unclear funding requirements and inadequate funding, and difficulty knowing how to plan for LTC or make LTC decisions. A potential solution may be an online LTC Guide designed to provide accurate information about the range of LTC services, with an emphasis on home and community-based services. This Guide was developed to address the gap in comprehensive LTC information identified in the findings of this study.

Dual role of the coactivator TORC2 in modulating hepatic glucose output and insulin signaling.

Under fasting conditions, the cAMP-responsive CREB coactivator TORC2 promotes glucose homeostasis by stimulating the gluconeogenic program in liver. Following its nuclear translocation in response to elevations in circulating glucagon, TORC2 regulates hepatic gene expression via an association with CREB on relevant promoters. Here, we show that, in parallel with their effects on glucose output, CREB and TORC2 also enhance insulin signaling in liver by stimulating expression of the insulin receptor substrate 2 (IRS2) gene. The induction of hepatic IRS2 during fasting appears critical for glucose homeostasis; knockdown of hepatic IRS2 expression leads to glucose intolerance, whereas hepatic IRS2 overexpression attenuates the gluconeogenic program and reduces fasting glucose levels. By stimulating the expression of IRS2 in conjunction with gluconeogenic genes, the CREB:TORC2 pathway thus triggers a feedback response that limits glucose output from the liver during fasting.

CREB controls hepatic lipid metabolism through nuclear hormone receptor PPAR-gamma.

Fasting triggers a series of hormonal cues that promote energy balance by inducing glucose output and lipid breakdown in the liver. In response to pancreatic glucagon and adrenal cortisol, the cAMP-responsive transcription factor CREB activates gluconeogenic and fatty acid oxidation programmes by stimulating expression of the nuclear hormone receptor coactivator PGC-1 (refs 2-5). In parallel, fasting also suppresses lipid storage and synthesis (lipogenic) pathways, but the underlying mechanism is unknown. Here we show that mice deficient in CREB activity have a fatty liver phenotype and display elevated expression of the nuclear hormone receptor PPAR-gamma, a key regulator of lipogenic genes. CREB inhibits hepatic PPAR-gamma expression in the fasted state by stimulating the expression of the Hairy Enhancer of Split (HES-1) gene, a transcriptional repressor that is shown here to be a mediator of fasting lipid metabolism in vivo. The coordinate induction of PGC-1 and repression of PPAR-gamma by CREB during fasting provides a molecular rationale for the antagonism between insulin and counter-regulatory hormones, and indicates a potential role for CREB antagonists as therapeutic agents in enhancing insulin sensitivity in the liver.

Assisted living pilot program: background, methods, and facility characteristics.

Objectives. The Department of Veterans Affairs (VA) funded assisted living (AL), adult family home (AFH), and residential care for the first time in the Assisted Living Pilot Program (ALPP). This article describes the background and methods of the ALPP evaluation and the characteristics and experiences of the facilities. Method. Facility data were collected from the contracting/inspection process and a survey of ALPP facilities and those contacted but not participating in ALPP. Results. Data on 131 participating facilities are presented: 41 AFHs, 47 assisted living facilities (ALFs), and 43 residential care facilities (RCFs). The average facility had 33 beds (about one quarter Medicaid beds), for-profit ownership, and private rooms for ALPP residents, and about half had private baths. About two thirds of ALPP AFH providers spoke a primary language other than English. Discussion. Findings indicate that a wide range of community facilities were willing to provide care to residents with heterogeneous needs on VA funding.

Assisted living pilot program: utilization and cost findings.

Objective. The Department of Veterans Affairs funded assisted living, adult family home, and adult residential care for the first time in the Assisted Living Pilot Program (ALPP). This article compares the use and cost for individuals that entered ALPP and a comparison group. Method. This was a nonrandomized study. The comparison group consisted of VA patients who were eligible but did not enter an ALPP facility. The ALPP (n = 393) and comparison (n = 259) groups were followed for 12 months to assess ALPP facility, case management, and health care costs. Results. ALPP facility and ALPP case management costs were respectively $5,560 and $2,830 per individual. Total health care costs, including ALPP costs, were $11,533 higher for the ALPP group compared to the comparison group after adjusting for baseline differences. Discussion. Although ALPP successfully helped individuals transition to longer term care in these facilities, it was more costly than the comparison group.

Assisted living pilot program: health outcomes.

Objectives. Assisted living programs demonstrate variation in structure and services. The Department of Veterans Affairs funded this care for the first time in the Assisted Living Pilot Program (ALPP). This article presents resident health outcomes and the relationship between facility characteristics and outcomes. Method. This article presents results on 393 ALPP residents followed for 12 months after admission to 95 facilities. Results. A total of 19.8% residents died, and the average activities of daily living impairment did not change significantly. Half of the residents remained in an ALPP facility, with the average resident spending 315 days in the community during the 12-month follow-up period. This article found a limited number of characteristics of structure and staffing to be significantly associated with outcomes. Discussion. If differences among facility characteristics are not clearly related to differences in outcomes, then choices among type of setting can be based on the match of needs to available services, location, or preferences.

Barriers to home and community-based service referrals: the physician's role.

The purpose of this study was to obtain information about Department of Veteran Affairs (VA) long-term care (LTC) referrals that could be used to develop interventions that increase the likelihood of referrals to home and community-based services (HCBS) instead of institutional care. This primarily qualitative study was conducted at five VA Medical Centers. The study used three linked methods: interviews with patients and informal caregivers; focus groups with LTC administrators, providers, and social workers; and written rankings of the barriers to HCBS referrals. We unexpectedly identified a cluster of findings indicating the importance of physicians' role in the LTC referral process and the need for more LTC training, particularly about HCBS.

Screening for Auditory Impairment-Which Hearing Assessment Test (SAI-WHAT): RCT design and baseline characteristics.

BACKGROUND: Effective screening programs should not merely detect presence of disease, but also lead to long-term benefit. We describe the rationale and design of the first randomized clinical trial to study the long-term effects of routine screening for hearing loss. We also describe the baseline characteristics of the randomized cohort. METHODS: We randomized 2305 veterans age 50 years or older to a control arm without screening, or to screening with: physiologic testing (AudioScope), a self-administered questionnaire (Hearing Handicap Inventory for the Elderly-Screening version [HHIE-S]), or both tests. The primary outcome measure will be hearing aid use one year after screening. We will also study a number of secondary outcomes, including appointments made with and visits to an audiologist, cases of aidable hearing loss, hearing aids dispensed, self-rated communication ability, and hearing-related quality of life. RESULTS: Baseline demographic and health status measures were evenly distributed across the screening arms. The percentage of patients who screened positive for hearing loss was 18.6%, 59.2%, and 63.6% for the AudioScope, HHIE-S, and combined screening arms, respectively. IMPLICATIONS: Long-term results are needed to gain insight into whether the AudioScope is associated with high rates of false negative screening, the HHIE-S is associated with high rates of false positive screening, or a combination of both. Identifying the best screening program will depend on determining which strategy leads to successful hearing aid use.

Characteristics of residents and providers in the assisted living pilot program.

PURPOSE: The number of residents in assisted living has rapidly increased, although these facilities still primarily serve people who can pay out of pocket. The U.S. Department of Veterans Affairs was authorized to provide this level of care for the first time in the Assisted Living Pilot Program (ALPP). We describe the residents and providers, comparing them across three facility types and other populations, to assess the characteristics and feasibility of this new approach. DESIGN AND METHODS: We assessed ALPP residents and providers across seven Veterans Affairs Medical Centers. We obtained information from medical records, assessment tools, and a provider survey. RESULTS: We report here on 743 residents placed from 2002 to 2004. The Department of Veterans Affairs contracted with 58 adult family homes, 56 assisted living facilities, and 46 residential care facilities. The average ALPP resident was a 70-year-old unmarried White man referred from an inpatient hospital and living in a private residence prior to placement. Adult family homes enrolled residents requiring greater levels of assistance with activities of daily living than other facility types. Assisted living facilities were less likely than adult family homes to admit residents with functional disabilities and less likely than either adult family homes or adult residential care facilities to admit residents with certain care needs. IMPLICATIONS: ALPP placed residents with a wide range of characteristics in community facilities that varied widely in size and services. This information can help determine the role of this type of care in and outside of the Department of Veterans Affairs.

Psychotropic use in community residential care facilities: A prospective cohort study.

BACKGROUND: Psychotropic medication use in community residential care (CRC) facilities has been reported to be similar to that found in nursing homes before the implementation of the Omnibus Budget Reconciliation Act of 1987. OBJECTIVES: The objectives of this study were to (1) describe patterns of psychotropic medication use at baseline and after 1 year of follow-up in adult residents aged > or =65 years supported by Medicaid in CRC facilities, (2) describe the quality of psychotropic use, and (3) examine the relationship between psychotropic use and resident and facility characteristics. METHODS: This was a planned analysis of a larger prospective cohort study conducted in CRC facilities (assisted living, adult family home, adult residential care) in a 3-county area in the state of Washington. Interviews and state Medicaid databases were used to collect resident characteristics (demographic data, medication use, activities of daily living, self-reported health, and frequency of memory and behavior problems) and facility characteristics (type, staffing, and occupancy rates). Residents were classified as users or nonusers of psychotropic medications. Suboptimal psychotropic use was defined as use of agents with a higher side-effect profile (tertiary amine tricyclic antidepressants, long-acting benzodiazepines, and low-potency conventional antipsychotics). Logistic regression was used to examine characteristics associated with any psychotropic use at baseline. RESULTS: The typical resident was a white woman, aged 83 years, receiving 7 medications. Nearly half (46.8%) of all residents used > or =1 psychotropic medication at baseline, whereas 16.7% used multiple agents. Antidepressants accounted for the greatest amount of psychotropic use (31.2%). Suboptimal antidepressants, sedative/anxiolytics, and antipsychotics were used by 19.3%, 16.7%, and 7.3% of medication users in each class, respectively. Only age (odds ratio [OR] = 0.97; 95% CI, 0.35-1.00), number of medications (OR = 1.06; 95% CI, 1.00-1.11), and the Revised Memory and Behavior Problems Checklist score (OR = 2.03; 95% CI, 1.28-3.23) were associated with psychotropic use at baseline. CONCLUSIONS: Psychotropic medication use was high in CRC facilities (46.8%), with antidepressants being the most frequently used drugs. Use of suboptimal (19.3% of antidepressant users, 16.7% of sedative/anxiolytic users, 7.3% of antipsychotic users) and multiple psychotropics (16.7%) was low.

Satisfaction with care among community residential care residents.

Measuring satisfaction with community residential care (CRC) is growing in importance but still in its infancy. The authors conducted interviews with 176 CRC residents and their providers. Logistic regression was used to identify resident and physical characteristics, policies and services, and aggregate resident characteristics associated with satisfaction. Residents had high levels of satisfaction, demonstrating most concern with the facility being able to meet their future needs and food quality. Resident demographics and health status were associated with satisfaction. Contrary to hypotheses, facility type (adult family home and assisted living) was the only facility characteristic strongly associated with satisfaction. Possible explanations include that the relationship between satisfaction and facility characteristics is more complex than expected, as well as significant challenges in measuring satisfaction and facility characteristics. The inconsistent results of previous satisfaction studies do not provide direction for imposition of uniform standards for facility characteristics, if the goal is improved satisfaction.

Association of body weight with condition-specific quality of life in male veterans.

PURPOSE: We hypothesized that obese adults with coronary heart disease, obstructive lung disease, or depression would report greater impairments in health-related quality of life owing to their angina, dyspnea, or depressive symptoms as compared with persons with normal body weight. METHODS: We analyzed cross-sectional data from the Ambulatory Care Quality Improvement Project, a multicenter study of veterans enrolled in general internal medicine clinics. Health-related quality of life was assessed using the Medical Outcomes Study Short Form-36, the Seattle Angina Questionnaire, the Seattle Obstructive Lung Disease Questionnaire, and the Hopkins Symptom Checklist for Depression. RESULTS: Compared with patients of normal weight (body mass index: 18.5 to 24.9 kg/m2), underweight patients (body mass index <18.5 kg/m2) reported health-related quality-of-life scores that were at least 5% lower (worse) in all 15 quality-of-life domains examined. Patients with class III obesity (body mass index > or =40 kg/m2) reported quality-of-life scores that were at least 5% lower than those of normal weight patients in eight domains. Scores of overweight patients (body mass index: 25 to 29.9 kg/m2) were higher (better) than those of normal weight patients in 11 domains. CONCLUSION: Body mass index was strongly associated with generic- and condition-specific health-related quality of life. Our results suggest that, when considering health-related quality-of-life outcomes among veterans, the optimal body mass index may be above the "normal" range. Further research should test the validity of the 1998 National Institutes of Health body mass index categories as predictors of health outcomes among veterans.