NLRP12 attenuates colon inflammation by maintaining colonic microbial diversity and promoting protective commensal bacterial growth

Inflammatory bowel diseases involve the dynamic interaction of host genetics, the microbiome and inflammatory responses. Here we found lower expression of NLRP12 (which encodes a negative regulator of innate immunity) in human ulcerative colitis, by comparing monozygotic twins and other patient cohorts. In parallel, Nlrp12 deficiency in mice caused increased basal colonic inflammation, which led to a less-diverse microbiome and loss of protective gut commensal strains (of the family Lachnospiraceae) and a greater abundance of colitogenic strains (of the family Erysipelotrichaceae). Dysbiosis and susceptibility to colitis associated with Nlrp12 deficency were reversed equally by treatment with antibodies targeting inflammatory cytokines and by the administration of beneficial commensal Lachnospiraceae isolates. Fecal transplants from mice reared in specific-pathogen-free conditions into germ-free Nlrp12-deficient mice showed that NLRP12 and the microbiome each contributed to immunological signaling that culminated in colon inflammation. These findings reveal a feed-forward loop in which NLRP12 promotes specific commensals that can reverse gut inflammation, while cytokine blockade during NLRP12 deficiency can reverse dysbiosis.

UNC2025, a MERTK Small-Molecule Inhibitor, Is Therapeutically Effective Alone and in Combination with Methotrexate in Leukemia Models

Purpose: MERTK tyrosine kinase is ectopically expressed in 30% to 50% of acute lymphoblastic leukemias (ALL) and more than 80% of acute myeloid leukemias (AML) and is a potential therapeutic target. Here, we evaluated the utility of UNC2025, a MERTK tyrosine kinase inhibitor, for treatment of acute leukemia.Experimental Design: Preclinical in vitro and in vivo assays using cell lines and primary leukemia patient samples were used to evaluate antileukemic effects of UNC2025.Results: UNC2025 potently inhibited prosurvival signaling, induced apoptosis, and reduced proliferation and colony formation in MERTK-expressing ALL and AML cell lines and patient samples. Approximately 30% of primary leukemia patient samples (78 of 261 total) were sensitive to UNC2025. Sensitive samples were most prevalent in the AML, T-ALL, and minimally differentiated (M0) AML subsets. UNC2025 inhibited MERTK in bone marrow leukemia cells and had significant therapeutic effects in xenograft models, with dose-dependent decreases in tumor burden and consistent two-fold increases in median survival, irrespective of starting disease burden. In a patient-derived AML xenograft model, treatment with UNC2025 induced disease regression. In addition, UNC2025 increased sensitivity to methotrexate in vivo, suggesting that addition of MERTK-targeted therapy to current cytotoxic regimens may be particularly effective and/or allow for chemotherapy dose reduction.Conclusions: The broad-spectrum activity mediated by UNC2025 in leukemia patient samples and xenograft models, alone or in combination with cytotoxic chemotherapy, supports continued development of MERTK inhibitors for treatment of leukemia. Clin Cancer Res; 23(6); 1481-92. ©2016 AACR.

Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291

Clostridium difficile is an anaerobic, gram-positive, spore-forming enteric pathogen that is associated with increasing morbidity and mortality and consequently poses an urgent threat to public health. Recurrence of a C. difficile infection (CDI) after successful treatment with antibiotics is high, occurring in 20-30% of patients, thus necessitating the discovery of novel therapeutics against this pathogen. Current animal models of CDI result in high mortality rates and thus do not approximate the chronic, insidious disease manifestations seen in humans with CDI. To evaluate therapeutics against C. difficile, a mouse model approximating human disease utilizing a clinically-relevant strain is needed. This protocol outlines the cefoperazone mouse model of CDI using a clinically-relevant and genetically-tractable strain, R20291. Techniques for clinical disease monitoring, C. difficile bacterial enumeration, toxin cytotoxicity, and histopathological changes throughout CDI in a mouse model are detailed in the protocol. Compared to other mouse models of CDI, this model is not uniformly lethal at the dose administered, allowing for the observation of a prolonged clinical course of infection concordant with the human disease. Therefore, this cefoperazone mouse model of CDI proves a valuable experimental platform to assess the effects of novel therapeutics on the amelioration of clinical disease and on the restoration of colonization resistance against C. difficile.

Intermittent At-Home Suctioning of Esophageal Content for Prevention of Recurrent Aspiration Pneumonia in 4 Dogs with Megaesophagus

Background

Megaesophagus carries a poor to guarded prognosis due to death from aspiration pneumonia. Options for medical management of regurgitation are limited to strategic oral or gastrostomy tube feeding.

Objectives

To describe the use and efficacy of intermittent esophageal suctioning to prevent regurgitation and associated episodes of aspiration pneumonia in dogs with megaesophagus.

Animals

Four dogs with acquired idiopathic megaesophagus and recurrent aspiration pneumonia.

Methods

Retrospective review of medical records of dogs with megaesophagus in which intermittent suctioning of esophageal content was employed for management of recurrent aspiration pneumonia.

Results

Intermittent suctioning of the esophagus was initiated in 4 dogs after failure of strict gastrostomy tube feeding failed to prevent regurgitation and repeated episodes of aspiration pneumonia. Suctioning was accomplished by esophagostomy tube in 3 dogs and per os in 1 dog. After initiation of esophageal suctioning, dogs survived for a median of 13.5 additional months (range, 10–30 months) during which time 2 dogs had no additional episodes of aspiration pneumonia and 2 dogs had infrequent episodes of pneumonia, but aspiration was suspected to be a contributing factor in their death. Complications included clogging of the esophagostomy tube, esophagostomy site infections, and esophagitis.

Conclusions and Clinical Importance

Use of intermittent esophageal suctioning in dogs with megaesophagus that continue to regurgitate despite gastrostomy tube feedings can reduce or abolish clinical episodes of aspiration pneumonia.

Abstract 680: Diet-induced obesity promotes tumor aggressiveness in genetically engineered mouse models of endometrial hyperplasia/cancer

Objective: To determine the effect of diet-induced obesity on the development of endometrial hyperplasia and cancer in genetically engineered mouse models.

Methods: The PTEN heterozygous mouse model for endometrial hyperplasia and the LKB1/p53 endometrioid endometrial cancer mouse model were used. Mice were divided into two dietary groups and fed either a high-fat diet (HFD, 60% calories from fat, obese) or a low-fat diet (LFD, 10% calories from fat, lean) beginning at 3 weeks of age until sacrifice at 32 weeks (PTEN model) and 12 weeks (LKB1/p53 model). At the time of sacrifice, mouse weight and uterine/tumor size were documented. A dedicated mouse pathologist reviewed uterine pathology. For the PTEN heterozygous mouse model, uterine pathology was determined to be simple hyperplasia (SH) if increased number of simple tubular glands were seen without atypia. Complex hyperplasia (CH) was defined as branching, papillary lumenal infoldings, or back-to-back glandular crowding with or without nuclear atypic.

Results: A total of 30 PTEN mice were examined, 14 in the obese group and 16 in the lean group. The HFD-fed mice were larger than the LFD-fed mice with a mean weight of 38.1 gm compared to 29.7 gm (p<0.001). There was no difference in uterine weight between the obese and lean mice, 0.30 versus 0.34 gm, respectively (p = 0.76). The lean mice were more likely to develop SH, 44% (n = 7) versus 7% (n = 1) in the obese group (p = 0.04). Of the obese mice, 57% (n = 8) developed CH (± atypia) compared to 31% (n = 5) of the lean mice (p = 0.16). A total of 35 LKB1/p53 mice were examined with 21 in the obese group and 14 in the lean group. The obese LKB1/p53 mice were larger (32.8 gm) than the lean mice (24.0 gm) (p = 0.033). The majority of the LKB1/p53 mice developed endometrioid adenocarcinoma with increased tumor size in the obese group (2.1 gm) versus lean group (0.79 gm) (p = 0.04).

Conclusions: Diet-induced obesity led to increased mean body weight in both mouse models. In the PTEN heterozygous mouse model, a trend towards more complex endometrial hyperplasia was found in the obese group along with a higher rate of simple hyperplasia in the lean group. Increased endometrial tumor size was seen in the obese versus lean LKB1/p53 mice, suggesting that obesity may lead to increased aggressiveness in endometrial cancer.

Citation Format: Leslie H. Clark, Chunxiao Zhou, Stephanie A. Montgomery, Paola A. Gehrig, Victoria Bae-Jump. Diet-induced obesity promotes tumor aggressiveness in genetically engineered mouse models of endometrial hyperplasia/cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 680.

A high capacity polymeric micelle of paclitaxel: Implication of high dose drug therapy to safety and in vivo anti-cancer activity

The poor solubility of paclitaxel (PTX), the commercially most successful anticancer drug, has long been hampering the development of suitable formulations. Here, we present translational evaluation of a nanoformulation of PTX, which is characterized by a facile preparation, extraordinary high drug loading of 50% wt. and PTX solubility of up to 45 g/L, excellent shelf stability and controllable, sub-100 nm size. We observe favorable in vitro and in vivo safety profiles and a higher maximum tolerated dose compared to clinically approved formulations. Pharmacokinetic analysis reveals that the higher dose administered leads to a higher exposure of the tumor to PTX. As a result, we observed improved therapeutic outcome in orthotopic tumor models including particularly faithful and aggressive "T11" mouse claudin-low breast cancer orthotopic, syngeneic transplants. The promising preclinical data on the presented PTX nanoformulation showcase the need to investigate new excipients and is a robust basis to translate into clinical trials.

Identification of candidate genes for chicken early- and late-feathering

Previous studies suggest that prolactin receptor (Prlr) is a potential causative gene for chicken early- (EF) and late-feathering (LF) phenotypes. In this study, we evaluated candidate genes for this trait and determined the expression of 3 genes, including Prlr, sperm flagellar protein 2 (Spef2), and their fusion gene, in the skins of one-day-old EF and LF chicks using RT-qPCR. Data indicated that Prlr expression in the skin did not show significant difference between EF and LF chicks, suggesting Prlr may not be a suitable candidate gene. In contrast, Spef2 expression in the skin displayed a significant difference between EF and LF chicks (P < 0.01), suggesting that Spef2 may be a good candidate gene for chicken feathering. Moreover, dPrlr/dSpef2, the fusion gene, was also a good candidate gene as it was expressed only in LF chicks. However, the expression of the fusion gene was much lower than that of Prlr Additionally, using strand-specific primers, we found that the fusion gene was transcribed in 2 directions (one from dPrlr promoter, another from dSpef2 promoter), which could result in the formation of a double strand RNA. In conclusion, both Spef2 and the fusion gene are good candidate genes for chicken feathering, but Prlr is not. The research on the function and regulation of the candidate genes will help elucidate the molecular basis of the chicken feathering trait.

Weight loss reduces basal-like breast cancer through kinome reprogramming

BACKGROUND

Obesity is associated with an aggressive subtype of breast cancer called basal-like breast cancer (BBC). BBC has no targeted therapies, making the need for mechanistic insight urgent. Reducing adiposity in adulthood can lower incidence of BBC in humans. Thus, this study investigated whether a dietary intervention to reduce adiposity prior to tumor onset would reverse HFD-induced BBC.

METHODS

Adult C3(1)-Tag mice were fed a low or high fat diet (LFD, HFD), and an obese group initially exposed to HFD was then switched to LFD to induce weight loss. A subset of mice was sacrificed prior to average tumor latency to examine unaffected mammary gland. Latency, tumor burden and progression was evaluated for effect of diet exposure. Physiologic, histology and proteomic analysis was undertaken to determine mechanisms regulating obesity and weight loss in BBC risk. Statistical analysis included Kaplan-Meier and log rank analysis to investigate latency. Student's t tests or ANOVA compared variables.

RESULTS

Mice that lost weight displayed significantly delayed latency compared to mice fed HFD, with latency matching those on LFD. Plasma leptin concentrations significantly increased with adiposity, were reduced to control levels with weight loss, and negatively correlated with tumor latency. HFD increased atypical ductal hyperplasia and ductal carcinoma in situ in mammary gland isolated prior to mean latency-a phenomenon that was lost in mice induced to lose weight. Importantly, kinome analysis revealed that weight loss reversed HFD-upregulated activity of PKC-α, PKD1, PKA, and MEK3 and increased AMPKα activity in unaffected mammary glands isolated prior to tumor latency.

CONCLUSIONS

Weight loss prior to tumor onset protected against the effects of HFD on latency and pre-neoplastic lesions including atypical ductal hyperplasia and DCIS. Using innovative kinomics, multiple kinases upstream of MAPK/P38α were demonstrated to be activated by HFD-induced weight gain and reversed with weight loss, providing novel targets in obesity-associated BBC. Thus, the HFD-exposed microenvironment that promoted early tumor onset was reprogrammed by weight loss and the restoration of a lean phenotype. Our work contributes to an understanding of underlying mechanisms associated with tumor and normal mammary changes that occur with weight loss.

cMET inhibitor crizotinib impairs angiogenesis and reduces tumor burden in the C3(1)-Tag model of basal-like breast cancer

Epidemiologic studies have associated obesity with increased risk of the aggressive basal-like breast cancer (BBC) subtype. Hepatocyte growth factor (HGF) signaling through its receptor, cMET, is elevated in obesity and is a pro-tumorigenic pathway strongly associated with BBC. We previously reported that high fat diet (HFD) elevated HGF, cMET, and phospho-cMET in normal mammary gland, with accelerated tumor development, compared to low fat diet (LFD)-fed lean controls in a murine model of BBC. We also showed that weight loss resulted in a significant reversal of HFD-induced effects on latency and elevation of HGF/cMET signaling in normal mammary and cMET in normal mammary and tumors. Here, we sought to inhibit BBC tumor progression in LFD- and HFD-fed C3(1)-Tag BBC mice using a small molecule cMET inhibitor, and began crizotinib treatment (50 mg/kg body weight by oral gavage) upon identification of the first palpable tumor. We next investigated if administering crizotinib in a window prior to tumor development would inhibit or delay BBC tumorigenesis. Treatment: Crizotinib significantly reduced mean tumor burden by 27.96 and 37.29 %, and mean tumor vascularity by 35.04 and 33.52 %, in our LFD- and HFD-fed C3(1)-Tag BBC mice, respectively. Prevention: Crizotinib significantly accelerated primary tumor progression in both diet groups but had no effect on total tumor progression or total tumor burden. In sum, cMET inhibition by crizotinib limited tumor development and microvascular density in basal-like tumor-bearing mice but did not appear to be an effective preventive agent for BBC.

Von Hippel-Lindau status influences phenotype of liver cancers arising from PTEN loss

BACKGROUND

PTEN loss contributes to the development of liver diseases including hepatic steatosis and both hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). The factors that influence the penetrance of these conditions are unclear. We explored the influence of sustained hypoxia signaling through co-deletion of Pten and Vhl in a murine model.

METHODS

We used a CreER-linked Keratin 18 mouse model to conditionally delete Pten, Vhl or both in somatic cells of adult mice, evaluating the resultant tumors by histology and gene expression microarray. Existing sets of gene expression data for human HCC and CC were examined for pathways related to those observed in the murine tumors, and a cohort of human CC samples was evaluated for relationships between HIF-1α expression and clinical outcomes.

RESULTS

Both Pten deletion genotypes developed liver tumors, but with differing phenotypes. Pten deletion alone led to large hepatic tumors with widespread hepatosteatosis. Co-deletion of Pten and Vhl with the Keratin 18 promoter resulted in reduced steatosis and a reduced tumor burden that was characterized by a trabecular architecture similar to CC. Genes associated with hepatic steatosis were coordinately expressed in the human HCC dataset, while genes involved in hypoxia response were upregulated in tumors from the human CC dataset. HIF-1α expression and overall survival were examined in an independent cohort of human CC tumors with no statistical differences uncovered.

CONCLUSION

Pten deletion in Keratin 18 expressing cells leads to aggressive tumor formation and widespread steatosis in mouse livers. Co-deletion of Vhl and Pten results in lower tumor burden with gene expression profiling suggesting a switch from a profile of lipid deposition to an expression profile more consistent with upregulation of the hypoxia response pathway. A relationship between tumor hypoxia signaling and altered hepatic steatotic response suggests that competing influences may alter tumor phenotypes.

Presumed primary ocular lymphangiosarcoma with metastasis in a miniature horse

A 7-year-old, 153.0-kg American Miniature mare presented for evaluation of keratoconjunctivitis of the right eye (OD). A superior palpebral conjunctival mass and stromal keratitis were diagnosed. The incisional biopsy diagnosis was a presumptive corneal hemangiosarcoma. Transpalpebral enucleation was performed, and histopathologic evaluation confirmed angiosarcoma of the conjunctiva, cornea, and extraocular muscles. The horse developed progressive epistaxis and orbital swelling following surgery. A systemic workup was performed 3 months after enucleation, revealing regrowth within the orbit and marked cranial cervical lymphomegaly, suggestive of metastasis. Humane euthanasia was performed, and necropsy confirmed a locally invasive periorbital tumor with metastasis to the submandibular tissue, submandibular lymph node, and thoracic inlet. Histopathologic evaluation of necropsy specimens revealed polygonal to spindle neoplastic cells lining neoplastic vascular channels lacking erythrocytes. Immunohistochemically, the neoplastic cells labeled strongly positive for PROX-1, vimentin, CD-31, VEGF, weakly positive for factor VIII-related antigen, and negative for collagen IV. Based on the clinical, histological, and immunohistochemical features of this tumor, a primary ocular lymphangiosarcoma with metastasis was diagnosed.

CD8+ T cells control Ross River virus infection in musculoskeletal tissues of infected mice

Ross River virus (RRV), chikungunya virus, and related alphaviruses cause debilitating polyarthralgia and myalgia. Mouse models of RRV and chikungunya virus have demonstrated a role for the adaptive immune response in the control of these infections. However, questions remain regarding the role for T cells in viral control, including the magnitude, location, and dynamics of CD8(+) T cell responses. To address these questions, we generated a recombinant RRV expressing the H-2(b)-restricted glycoprotein 33 (gp33) determinant derived from the glycoprotein of lymphocytic choriomeningitis virus. Using tetramers, we tracked gp33-specific CD8(+) T cells during RRV-lymphocytic choriomeningitis virus infection. We found that acute RRV infection induces activation of CD8(+) T cell responses in lymphoid and musculoskeletal tissues that peak from 10-14 d postinoculation, suggesting that CD8(+) T cells contribute to control of acute RRV infection. Mice genetically deficient for CD8(+) T cells or wild-type mice depleted of CD8(+) T cells had elevated RRV loads in skeletal muscle tissue, but not joint-associated tissues, at 14 d postinoculation, suggesting that the ability of CD8(+) T cells to control RRV infection is tissue dependent. Finally, adoptively transferred T cells were capable of reducing RRV loads in skeletal muscle tissue of Rag1(-/-) mice, indicating that T cells can contribute to the control of RRV infection in the absence of B cells and Ab. Collectively, these data demonstrate a role for T cells in the control of RRV infection and suggest that the antiviral capacity of T cells is controlled in a tissue-specific manner.

A gnotobiotic mouse model demonstrates that dietary fiber protects against colorectal tumorigenesis in a microbiota- and butyrate-dependent manner

Whether dietary fiber protects against colorectal cancer is controversial because of conflicting results from human epidemiologic studies. However, these studies and mouse models of colorectal cancer have not controlled the composition of gut microbiota, which ferment fiber into short-chain fatty acids such as butyrate. Butyrate is noteworthy because it has energetic and epigenetic functions in colonocytes and tumor-suppressive properties in colorectal cancer cell lines. We used gnotobiotic mouse models colonized with wild-type or mutant strains of a butyrate-producing bacterium to demonstrate that fiber does have a potent tumor-suppressive effect but in a microbiota- and butyrate-dependent manner. Furthermore, due to the Warburg effect, butyrate was metabolized less in tumors where it accumulated and functioned as a histone deacetylase (HDAC) inhibitor to stimulate histone acetylation and affect apoptosis and cell proliferation. To support the relevance of this mechanism in human cancer, we demonstrate that butyrate and histone-acetylation levels are elevated in colorectal adenocarcinomas compared with normal colonic tissues.

SIGNIFICANCE

These results, which link diet and microbiota to a tumor-suppressive metabolite, provide insight into conflicting epidemiologic findings and suggest that probiotic/prebiotic strategies can modulate an endogenous HDAC inhibitor for anticancer chemoprevention without the adverse effects associated with synthetic HDAC inhibitors used in chemotherapy.

Genetic ablation of arginase 1 in macrophages and neutrophils enhances clearance of an arthritogenic alphavirus

Chikungunya virus (CHIKV) and Ross River virus (RRV) cause a debilitating, and often chronic, musculoskeletal inflammatory disease in humans. Macrophages constitute the major inflammatory infiltrates in musculoskeletal tissues during these infections. However, the precise macrophage effector functions that affect the pathogenesis of arthritogenic alphaviruses have not been defined. We hypothesized that the severe damage to musculoskeletal tissues observed in RRV- or CHIKV-infected mice would promote a wound-healing response characterized by M2-like macrophages. Indeed, we found that RRV- and CHIKV-induced musculoskeletal inflammatory lesions, and macrophages present in these lesions, have a unique gene-expression pattern characterized by high expression of arginase 1 and Ym1/Chi3l3 in the absence of FIZZ1/Relmα that is consistent with an M2-like activation phenotype. Strikingly, mice specifically deleted for arginase 1 in neutrophils and macrophages had dramatically reduced viral loads and improved pathology in musculoskeletal tissues at late times post-RRV infection. These findings indicate that arthritogenic alphavirus infection drives a unique myeloid cell activation program in inflamed musculoskeletal tissues that inhibits virus clearance and impedes disease resolution in an arginase 1-dependent manner.

A mouse model of chikungunya virus-induced musculoskeletal inflammatory disease: evidence of arthritis, tenosynovitis, myositis, and persistence

Chikungunya virus (CHIKV), an emerging mosquito-borne Alphavirus, causes debilitating rheumatic disease in humans that can last for weeks to months. Starting in 2004, a CHIKV outbreak in the Indian Ocean region affected millions of people, and infected travelers introduced CHIKV to new regions. The pathogenesis of CHIKV is poorly understood, and no approved vaccines or specific therapies exist. A major challenge to the study of CHIKV disease is the lack of a small animal model that recapitulates the major outcomes of human infection. In this study, the pathogenesis of CHIKV in C57BL/6J mice was investigated using biological and molecular clones of CHIKV isolated from human serum (CHIKV SL15649). After 14-day-old mice were inoculated with CHIKV SL15649 in the footpad, they displayed reduced weight gain and swelling of the inoculated limb. Histologic analysis of hind limb sections revealed severe necrotizing myositis, mixed inflammatory cell arthritis, chronic active tenosynovitis, and multifocal vasculitis. Interestingly, these disease signs and viral RNA persisted in musculoskeletal tissues for at least 3 weeks after inoculation. This work demonstrates the development of a mouse model of CHIKV infection with clinical manifestations and histopathologic findings that are consistent with the disease signs of CHIKV-infected humans, providing a useful tool for studying viral and host factors that drive CHIKV pathogenesis and for evaluating potential therapeutics against this emerging viral disease.

Modulation of type I IFN induction by a virulence determinant within the alphavirus nsP1 protein

Alphaviruses are mosquito-borne viruses that cause serious human and animal diseases. Previous studies demonstrated that a determinant within the nsP1/nsP2 cleavage domain of the virulent Sindbis AR86 virus played a key role in regulating adult mouse virulence without adversely affecting viral replication. Additional characterization of this determinant demonstrated that a virus with the attenuating mutation induced more type I IFN production both in vivo and in vitro. Interestingly, this phenotype was not specific to the Sindbis AR86 virus, as a similar mutation in a distantly related alphavirus, Ross River Virus (RRV), also led to enhanced IFN induction. This effect was independent of virus-induced host shutoff, since IRF-3 phosphorylation, which occurs independently of de novo host transcription/translation, was induced more robustly in cells infected with the mutant viruses. Altogether, these results demonstrate that critical determinants within the nsP1/nsP2 cleavage domain play an important role in regulating alphavirus-induced IFN responses.

Analysis of health-related quality of life and costs based on a randomised clinical trial of escitalopram for relapse prevention in patients with generalised social anxiety disorder

BACKGROUND

Social anxiety disorder (SAD) is associated with substantial reduction in health-related quality of life (HRQoL). Escitalopram has proven efficacy in the short-term treatment of SAD and prevention of relapse.

OBJECTIVES

To determine whether the clinical effects of treatment translated into HRQoL benefits and to investigate costs of SAD treatment.

METHODS

Data on HRQoL and resource utilisation were collected in a previously published clinical trial of escitalopram in relapse prevention. Among 517 patients, 371 responded to 12 weeks of open-label treatment with escitalopram and were randomised to escitalopram or placebo for 24 weeks. HRQoL was assessed using the short form (SF)-36 instrument and SF-6D utilities (preference-based index scores for overall HRQoL) were calculated. Costs were calculated for responders over the acute phase and for non-relapsed patients over the continuation phase, applying UK unit costs.

RESULTS

Health-related quality of life was significantly improved after the acute phase when compared with baseline. The SF-6D utility increased by 0.047 in responders (p < 0.0001) and 0.021 in non-responders (p = 0.0005). Healthcare costs were non-significantly lower in acute phase than during prestudy phase (p = 0.0587 from NHS perspective), as were productivity costs (p = 0.1440). HRQoL at last visit was lower in relapsed than non-relapsed patients. The difference in utility was -0.026 (p = 0.0007). Healthcare and productivity costs were non-significantly lower in the escitalopram group than in the placebo group.

CONCLUSIONS

Both effective acute treatment of SAD and prevention of relapse with escitalopram are associated with significant HRQoL benefits. Despite some limitations, the cost analysis suggests that savings in physician-visits and inpatient care may offset drug acquisition costs.

Nuclear import and export of Venezuelan equine encephalitis virus nonstructural protein 2

Many RNA viruses, which replicate predominantly in the cytoplasm, have nuclear components that contribute to their life cycle or pathogenesis. We investigated the intracellular localization of the multifunctional nonstructural protein 2 (nsP2) in mammalian cells infected with Venezuelan equine encephalitis virus (VEE), an important, naturally emerging zoonotic alphavirus. VEE nsP2 localizes to both the cytoplasm and the nucleus of mammalian cells in the context of infection and also when expressed alone. Through the analysis of a series of enhanced green fluorescent protein fusions, a segment of nsP2 that completely localizes to the nucleus of mammalian cells was identified. Within this region, mutation of the putative nuclear localization signal (NLS) PGKMV diminished, but did not obliterate, the ability of the protein to localize to the nucleus, suggesting that this sequence contributes to the nuclear localization of VEE nsP2. Furthermore, VEE nsP2 specifically interacted with the nuclear import protein karyopherin-alpha1 but not with karyopherin-alpha2, -3, or -4, suggesting that karyopherin-alpha1 transports nsP2 to the nucleus during infection. Additionally, a novel nuclear export signal (NES) was identified, which included residues L526 and L528 of VEE nsP2. Leptomycin B treatment resulted in nuclear accumulation of nsP2, demonstrating that nuclear export of nsP2 is mediated via the CRM1 nuclear export pathway. Disruption of either the NLS or the NES in nsP2 compromised essential viral functions. Taken together, these results establish the bidirectional transport of nsP2 across the nuclear membrane, suggesting that a critical function of nsP2 during infection involves its shuttling between the cytoplasm and the nucleus.

Ribosomal protein S6 associates with alphavirus nonstructural protein 2 and mediates expression from alphavirus messages

Although alphaviruses dramatically alter cellular function within hours of infection, interactions between alphaviruses and specific host cellular proteins are poorly understood. Although the alphavirus nonstructural protein 2 (nsP2) is an essential component of the viral replication complex, it also has critical auxiliary functions that determine the outcome of infection in the host. To gain a better understanding of nsP2 function, we sought to identify cellular proteins with which Venezuelan equine encephalitis virus nsP2 interacted. We demonstrate here that nsP2 associates with ribosomal protein S6 (RpS6) and that nsP2 is present in the ribosome-containing fractions of a polysome gradient, suggesting that nsP2 associates with RpS6 in the context of the whole ribosome. This result was noteworthy, since viral replicase proteins have seldom been described in direct association with components of the ribosome. The association of RpS6 with nsP2 was detected throughout the course of infection, and neither the synthesis of the viral structural proteins nor the presence of the other nonstructural proteins was required for RpS6 interaction with nsP2. nsP1 also was associated with RpS6, but other nonstructural proteins were not. RpS6 phosphorylation was dramatically diminished within hours after infection with alphaviruses. Furthermore, a reduction in the level of RpS6 protein expression led to diminished expression from alphavirus subgenomic messages, whereas no dramatic diminution in cellular translation was observed. Taken together, these data suggest that alphaviruses alter the ribosome during infection and that this alteration may contribute to differential translation of host and viral messages.

Antidepressants and seizures: emphasis on newer agents and clinical implications

Seizures are a known, relatively rare, consequence of antidepressant treatment. Risk estimates vary depending on the study, source of data and patient population, predisposed vs. nonpredisposed. For newer antidepressants (e.g. selective serotonin reuptake inhibitors, bupropion, mirtazepine, etc.), the risk is generally considered to be low (0.0%-0.4%) and not very different from the incidence of first seizure in the general population (0.07%-0.09%). Risk with tricyclic antidepressants at effective therapeutic doses is relatively high (0.4% to 1-2%). Seizure following overdose is a significant and relatively frequent event for some antidepressants. Patients being considered for antidepressant treatment should be screened for predisposition to seizures. Predisposed patients should receive antidepressants cautiously. The seizure potential of antidepressants in patients without a predisposition is low, especially for newer antidepressants. Seizure risk, along with other drug-related considerations, e.g. weight gain, sexual dysfunction and sedation, should be considered when prescribing an antidepressant.