Alpha-Ketoglutarate Regulates Tnfrsf12a/Fn14 Expression via Histone Modification and Prevents Cancer-Induced Cachexia.

Previous studies have shown that inhibition of TNF family member FN14 (gene: TNFRSF12A) in colon tumors decreases inflammatory cytokine expression and mitigates cancer-induced cachexia. However, the molecular mechanisms underlying the regulation of FN14 expression remain unclear. Tumor microenvironments are often devoid of nutrients and oxygen, yet how the cachexic response relates to the tumor microenvironment and, importantly, nutrient stress is unknown. Here, we looked at the connections between metabolic stress and FN14 expression. We found that TNFRSF12A expression was transcriptionally induced during glutamine deprivation in cancer cell lines. We also show that the downstream glutaminolysis metabolite, alpha-ketoglutarate (aKG), is sufficient to rescue glutamine-deprivation-promoted TNFRSF12A induction. As aKG is a co-factor for histone de-methylase, we looked at histone methylation and found that histone H3K4me3 at the Tnfrsf12a promoter is increased under glutamine-deprived conditions and rescued via DM-aKG supplementation. Finally, expression of Tnfrsf12a and cachexia-induced weight loss can be inhibited in vivo by DM-aKG in a mouse cancer cachexia model. These findings highlight a connection between metabolic stress and cancer cachexia development.

A TGF-ß/KLF10 signaling axis regulates atrophy-associated genes to induce muscle wasting in pancreatic cancer.

Cancer cachexia, and its associated complications, represent a large and currently untreatable roadblock to effective cancer management. Many potential therapies have been proposed and tested-including appetite stimulants, targeted cytokine blockers, and nutritional supplementation-yet highly effective therapies are lacking. Innovative approaches to treating cancer cachexia are needed. Members of the Kruppel-like factor (KLF) family play wide-ranging and important roles in the development, maintenance, and metabolism of skeletal muscle. Within the KLF family, we identified KLF10 upregulation in a multitude of wasting contexts-including in pancreatic, lung, and colon cancer mouse models as well as in human patients. We subsequently interrogated loss-of-function of KLF10 as a potential strategy to mitigate cancer associated muscle wasting. In vivo studies leveraging orthotopic implantation of pancreas cancer cells into wild-type and KLF10 KO mice revealed significant preservation of lean mass and robust suppression of pro-atrophy muscle-specific ubiquitin ligases Trim63 and Fbxo32, as well as other factors implicated in atrophy, calcium signaling, and autophagy. Bioinformatics analyses identified Transforming growth factor beta (TGF-ß), a known inducer of KLF10 and cachexia promoting factor, as a key upstream regulator of KLF10. We provide direct in vivo evidence that KLF10 KO mice are resistant to the atrophic effects of TGF-ß. ChIP-based binding studies demonstrated direct binding to Trim63, a known wasting-associated atrogene. Taken together, we report a critical role for the TGF-ß/KLF10 axis in the etiology of pancreatic cancer-associated muscle wasting and highlight the utility of targeting KLF10 as a strategy to prevent muscle wasting and limit cancer-associated cachexia.

Unlocking Prognostic Genes and Multi-Targeted Therapeutic Bioactives from Herbal Medicines to Combat Cancer-Associated Cachexia: A Transcriptomics and Network Pharmacology Approach.

Cachexia is a devastating fat tissue and muscle wasting syndrome associated with every major chronic illness, including cancer, chronic obstructive pulmonary disease, kidney disease, AIDS, and heart failure. Despite two decades of intense research, cachexia remains under-recognized by oncologists. While numerous drug candidates have been proposed for cachexia treatment, none have achieved clinical success. Only a few drugs are approved by the FDA for cachexia therapy, but a very low success rate is observed among patients. Currently, the identification of drugs from herbal medicines is a frontier research area for many diseases. In this milieu, network pharmacology, transcriptomics, cheminformatics, and molecular docking approaches were used to identify potential bioactive compounds from herbal medicines for the treatment of cancer-related cachexia. The network pharmacology approach is used to select the 32 unique genes from 238 genes involved in cachexia-related pathways, which are targeted by 34 phytocompounds identified from 12 different herbal medicines used for the treatment of muscle wasting in many countries. Gene expression profiling and functional enrichment analysis are applied to decipher the role of unique genes in cancer-associated cachexia pathways. In addition, the pharmacological properties and molecular interactions of the phytocompounds were analyzed to find the target compounds for cachexia therapy. Altogether, combined omics and network pharmacology approaches were used in the current study to untangle the complex prognostic genes involved in cachexia and phytocompounds with anti-cachectic efficacy. However, further functional and experimental validations are required to confirm the efficacy of these phytocompounds as commercial drug candidates for cancer-associated cachexia.

Taurine Supplementation Inhibits the Expression of Atrogin-1 and MURF-1, Protein Degradation Marker Genes, in Skeletal Muscle of C26-Induced Cachexia Mouse Model.

This study was designed to investigate the therapeutic effects of taurine in attenuating muscle atrophy. C26 carcinoma cells were cultured and injected into the scapulae of Balb/c mice with 1 × 106 cells. Taurine (200 µl suspension) was orally administered at the concentration of 200 mg/kg of body weight for 2 weeks. Femur muscle tissue, spleen, and gonadal fat tissue were collected and weighed. Muscle tissue was stained by H&E for histopathological analysis. The transcriptional expression of atrogin-1 and MuRF-1 gene was checked by real-time PCR. C26 cells, which induced tumor growth, caused a loss in muscle mass and gonadal fat tissue mass. Simultaneously, there was an increase in spleen and tumor tissue mass. In contrast, taurine supplementation showed a downregulatory effect on the transcriptional expression profile of muscle degradative factors atrogin-1 and MuRF-1. Our findings suggest that taurine has the potential to inhibit muscle atrophy and can be developed as a safe treatment option against muscle loss in sarcopenia patients.

Development of a traditional Chinese medicine-based agent for the treatment of cancer cachexia.

BACKGROUND: Despite recent advances in understanding the pathophysiology of cancer cachexia, prevention/treatment of this debilitating disease remains an unmet medical need. METHODS: We developed an integrated, multi-tiered strategy involving both in vitro and in vivo muscle atrophy platforms to identify traditional Chinese medicine (TCM)-based anti-cachectic agents. In the initial screening, we used inflammatory cytokine-induced atrophy of C2C12 myotubes as a phenotypic screening platform to assess the protective effects of TCMs. The selected TCMs were then evaluated for their abilities to protect Caenorhabditis elegans from age-related reduction of mobility and contractility, followed by the C-26 colon adenocarcinoma mouse model of cachexia to confirm the anti-muscle atrophy effects (body/skeletal muscle weights, fibre size distribution, grip strengths, and serum IL-6). Transcriptome analysis, quantitative real-time polymerase chain reaction, and immunoblotting were performed to gain understanding of the potential mechanism(s) by which effective TCM protected against C26 tumour-induced muscle atrophy. RESULTS: Of 29 widely used TCMs, Dioscorea radix (DR) and Mu Dan Pi (MDP) showed a complete protection (all P values, 0.0002) vis-à-vis C26 conditioned medium control in the myotube atrophy platform. MDP exhibited a unique ability to ameliorate age-associated decreases in worm mobility, accompanied by improved total body contractions, relative to control (P < 0.0001 and <0.01, respectively), which, however, was not noted with DR. This differential in vivo protective effect between MDP and DR was also confirmed in the C-26 mouse model. MDP at 1000 mg/kg (MDP-H) was effective in protecting body weight loss (P < 0.05) in C-26 tumour-bearing mice without changing food or water intake, accompanied by the restoration of the fibre size distribution of hindleg skeletal muscles (P < 0.0001) and the forelimb grip strength (P < 0.05). MDP-treated C-26-tumour-bearing mice were alert, showed normal posture and better body conditions, and exhibited lower serum IL-6 levels (P = 0.06) relative to vehicle control. This decreased serum IL-6 was associated with the in vitro suppressive effect of MDP (25 and 50 µg/mL) on IL-6 secretion into culture medium by C26 cells. RNA-seq analysis, followed by quantitative real-time polymerase chain reaction and/or immunoblotting, shows that MDP's anti-cachectic effect was attributable to its ability to reverse the C-26 tumour-induced re-programming of muscle homoeostasis-associated gene expression, including that of two cachexia drivers (MuRF1 and Atrogin-1), in skeletal muscles. CONCLUSIONS: All these findings suggest the translational potential of MDP to foster new strategies for the prevention and/or treatment of cachexia. The protective effect of MDP on other types of muscle atrophy such as sarcopenia might warrant investigations.

Leucine-Rich Diet Improved Muscle Function in Cachectic Walker 256 Tumour-Bearing Wistar Rats.

Skeletal muscle atrophy occurs in several pathological conditions, such as cancer, especially during cancer-induced cachexia. This condition is associated with increased morbidity and poor treatment response, decreased quality of life, and increased mortality in cancer patients. A leucine-rich diet could be used as a coadjutant therapy to prevent muscle atrophy in patients suffering from cancer cachexia. Besides muscle atrophy, muscle function loss is even more important to patient quality of life. Therefore, this study aimed to investigate the potential beneficial effects of leucine supplementation on whole-body functional/movement properties, as well as some markers of muscle breakdown and inflammatory status. Adult Wistar rats were randomly distributed into four experimental groups. Two groups were fed with a control diet (18% protein): Control (C) and Walker 256 tumour-bearing (W), and two other groups were fed with a leucine-rich diet (18% protein + 3% leucine): Leucine Control (L) and Leucine Walker 256 tumour-bearing (LW). A functional analysis (walking, behaviour, and strength tests) was performed before and after tumour inoculation. Cachexia parameters such as body weight loss, muscle and fat mass, pro-inflammatory cytokine profile, and molecular and morphological aspects of skeletal muscle were also determined. As expected, Walker 256 tumour growth led to muscle function decline, cachexia manifestation symptoms, muscle fibre cross-section area reduction, and classical muscle protein degradation pathway activation, with upregulation of FoxO1, MuRF-1, and 20S proteins. On the other hand, despite having no effect on the walking test, inflammation status or muscle oxidative capacity, the leucine-rich diet improved muscle strength and behaviour performance, maintained body weight, fat and muscle mass and decreased some protein degradation markers in Walker 256 tumour-bearing rats. Indeed, a leucine-rich diet alone could not completely revert cachexia but could potentially diminish muscle protein degradation, leading to better muscle functional performance in cancer cachexia.

The Extract of Arctium lappa L. Fruit (Arctii Fructus) Improves Cancer-Induced Cachexia by Inhibiting Weight Loss of Skeletal Muscle and Adipose Tissue.

BACKGROUND: Cachexia induced by cancer is a systemic wasting syndrome and it accompanies continuous body weight loss with the exhaustion of skeletal muscle and adipose tissue. Cancer cachexia is not only a problem in itself, but it also reduces the effectiveness of treatments and deteriorates quality of life. However, effective treatments have not been found yet. Although Arctii Fructus (AF) has been studied about several pharmacological effects, there were no reports on its use in cancer cachexia. METHODS: To induce cancer cachexia in mice, we inoculated CT-26 cells to BALB/c mice through subcutaneous injection and intraperitoneal injection. To mimic cancer cachexia in vitro, we used conditioned media (CM), which was CT-26 colon cancer cells cultured medium. RESULTS: In in vivo experiments, AF suppressed expression of interleukin (IL)-6 and atrophy of skeletal muscle and adipose tissue. As a result, the administration of AF decreased mortality by preventing weight loss. In adipose tissue, AF decreased expression of uncoupling protein 1 (UCP1) by restoring AMP-activated protein kinase (AMPK) activation. In in vitro model, CM increased muscle degradation factors and decreased adipocytes differentiation factors. However, these tendencies were ameliorated by AF treatment in C2C12 myoblasts and 3T3-L1 cells. CONCLUSION: Taken together, our study demonstrated that AF could be a therapeutic supplement for patients suffering from cancer cachexia.

Preventive effects of medium-chain triglycerides supplementation on the oxidative capacity in skeletal muscle under cachectic condition.

Cachexia is a multifactorial condition characterized by muscle mass loss and induces metabolic dysfunction of the skeletal muscles. The preventive effects of medium-chain triglycerides (MCT) supplementation on the oxidative capacity in skeletal muscle under cachectic condition were investigated in the present study. ICR mice were randomly divided into four groups; control, lipopolysaccharide (LPS), LPS plus long-chain triglycerides (LCT) and LPS plus MCT supplementation. LCT and MCT oil were administered to the LPS + LCT and LPS + MCT groups orally (5.0 g/kg body weight/day) by a catheter for one week. Cachexia was induced in the LPS, LPS + LCT, and LPS + MCT groups via LPS injection (7.5 mg/kg body weight, i.p.) after the supplementation. LPS induced a reduction of ketone bodies concentration in blood plasma. LPS also induced a decrease in succinate dehydrogenase activity and PGC-1α expression level in tibialis anterior muscles. Meanwhile, MCT supplementation suppressed a decrease in ketone bodies concentration and succinate dehydrogenase activity. In addition, MCT supplementation increased the level of citrate synthase activity in the muscles. These results suggested the preventive effect of MCT supplementation on oxidative capacity in skeletal muscle and the involvements of ketone bodies regulation under cachectic condition.

Differential Metabolic Responses to Adipose Atrophy Associated with Cancer Cachexia and Caloric Restriction in Rats and the Effect of Rikkunshito in Cancer Cachexia.

Despite the similar phenotypes, including weight loss, reduction of food intake, and lower adiposity, associated with caloric restriction (CR) and cancer cachexia (CC), CC is a progressive wasting syndrome, while mild CR improves whole body metabolism. In the present study, we compared adipose metabolic changes in a novel rat model of CC, mild CR (70% of the food intake of control rats, which is similar to the food consumption of CC rats), and severe CR (30% of the food intake of controls). We show that CC and severe CR are associated with much smaller adipocytes with significantly lower mitochondrial DNA content; but, that mild CR is not. CC and both mild and severe CR similarly upregulated proteins involved in lipolysis. CC also downregulated proteins involved in fatty acid biosynthesis, but mild CR upregulated these. These findings suggest that CC might impair de novo fatty acid biosynthesis and reduce mitochondrial biogenesis, similar to severe CR. We also found that rikkunshito, a traditional Japanese herbal medicine, does not ameliorate the enhanced lipolysis and mitochondrial impairment, but rather, rescues de novo fatty acid biosynthesis, suggesting that rikkunshito administration might have partially similar effects to mild CR.

Skeletal muscle atrophy and dysfunction in breast cancer patients: role for chemotherapy-derived oxidant stress.

How breast cancer and its treatments affect skeletal muscle is not well defined. To address this question, we assessed skeletal muscle structure and protein expression in 13 women who were diagnosed with breast cancer and receiving adjuvant chemotherapy following tumor resection and 12 nondiseased controls. Breast cancer patients showed reduced single-muscle fiber cross-sectional area and fractional content of subsarcolemmal and intermyofibrillar mitochondria. Drugs commonly used in breast cancer patients (doxorubicin and paclitaxel) caused reductions in myosin expression, mitochondrial loss, and increased reactive oxygen species (ROS) production in C2C12 murine myotube cell cultures, supporting a role for chemotherapeutics in the atrophic and mitochondrial phenotypes. Additionally, concurrent treatment of myotubes with the mitochondrial-targeted antioxidant MitoQ prevented chemotherapy-induced myosin depletion, mitochondrial loss, and ROS production. In patients, reduced mitochondrial content and size and increased expression and oxidation of peroxiredoxin 3, a mitochondrial peroxidase, were associated with reduced muscle fiber cross-sectional area. Our results suggest that chemotherapeutics may adversely affect skeletal muscle in patients and that these effects may be driven through effects of these drugs on mitochondrial content and/or ROS production.

Lung Cancer Cachexia: Can Molecular Understanding Guide Clinical Management?

Cachexia has been recognized for a long time as an adverse effect of cancer. It is associated with reduced physical function, reduced tolerance to anticancer therapy, and reduced survival. This wasting syndrome is mainly known for an ongoing loss of skeletal muscle leading to progressive functional impairment and is driven by a variable combination of reduced food intake and abnormal metabolism. Cytokines derived from host immune system or the tumor itself is believed to play a role in promoting cancer cachexia. Circulating levels of cytokines, including IL-1α, IL-6, and TNFα have been identified in cancer patients but they probably only represent a small part of a changed and abnormal metabolism. Murine models have shown that browning of white adipose tissue (WAT) takes place early in the progression of cancer cachexia. Thus, browning of white adipose tissue is believed to be a strong contributor to the increased energy expenditure common in cachectic patients. Despite the severe implications of cancer cachexia for the patients and extensive research efforts, a more coherent and mechanistic explanation of the syndrome is lacking, and for many clinicians, cancer cachexia is still a vague concept. From a lung cancer perspective this commentary reviews the current knowledge on cancer cachexia mechanisms and identifies specific ways of clinical management regarding food intake, systemic inflammation, and muscular dysfunction. Much of what we know comes from preclinical studies. More translational research is needed for a future cancer cachexia screening tool to guide clinicians, and here possible variables for a cancer cachexia screening tool are considered.

Sosiho­tang ameliorates cachexia­related symptoms in mice bearing colon 26 adenocarcinoma by reducing systemic inflammation and muscle loss.

Cachexia accompanied by muscle wasting is a key determinant of poor prognosis in cancer patients and cancer­related death. Previous studies have demonstrated that inflammatory cytokines such as interleukin­6 (IL­6), tumor necrosis factor­α (TNF­α), IL­1 and interferon­Î³ (IFN­Î³) secreted from host cells and tumor cells participate in skeletal muscle wasting followed by severe loss of body weight. Therefore, blockade of the inflammatory response is thought to be a logical target for pharmacological and nutritional interventions to preserve skeletal muscle mass under cachectic conditions. Sosiho­tang (SO; Xiaocharihu­tang in Chinese and Sho­saiko­to in Japanese) is an Oriental herbal medicine that has been used to treat chronic hepatic diseases and to control fever. In recent studies, SO inhibited the production of inflammatory cytokines in lipopolysaccharide (LPS)­stimulated macrophages, prevented thrombus formation and suppressed cancer progression. However, the anti­cachectic activity of SO in tumor­bearing mice has not yet been examined. In the present study, we characterized the effect of SO administration on cancer­induced cachexia in CT­26­bearing mice, and elucidated the anti­cachectic mechanisms. Daily oral administration of SO at doses of 50 and 100 mg/kg to CT­26­bearing mice significantly retarded tumor growth and prevented the loss of final body weight, carcass weight, heart weight, gastrocnemius muscle, and epididymal fat, compared with saline­treated control mice. In addition, serum IL­6 levels elevated by cancer were decreased by SO administration. In the J774A.1 macrophage cell line, SO efficiently suppressed LPS­mediated increases in inducible nitric oxide synthase (iNOS) expression, nitric oxide (NO), and procachectic inflammatory cytokine production through inhibition of nuclear factor­κB (NF­κB) and p38 activation. In addition, SO attenuated muscle atrophy caused by cancer cells by affecting myoblast proliferation and differentiation, and C2C12 myotube wasting. Taken together, these results suggest that SO is a safe and useful anti­cachectic therapy for cancer patients with severe weight loss.

Involvement of microRNAs in the regulation of muscle wasting during catabolic conditions.

Loss of muscle proteins and the consequent weakness has important clinical consequences in diseases such as cancer, diabetes, chronic heart failure, and in aging. In fact, excessive proteolysis causes cachexia, accelerates disease progression, and worsens life expectancy. Muscle atrophy involves a common pattern of transcriptional changes in a small subset of genes named atrophy-related genes or atrogenes. Whether microRNAs play a role in the atrophy program and muscle loss is debated. To understand the involvement of miRNAs in atrophy we performed miRNA expression profiling of mouse muscles under wasting conditions such as fasting, denervation, diabetes, and cancer cachexia. We found that the miRNA signature is peculiar of each catabolic condition. We then focused on denervation and we revealed that changes in transcripts and microRNAs expression did not occur simultaneously but were shifted. Indeed, whereas transcriptional control of the atrophy-related genes peaks at 3 days, changes of miRNA expression maximized at 7 days after denervation. Among the different miRNAs, microRNA-206 and -21 were the most induced in denervated muscles. We characterized their pattern of expression and defined their role in muscle homeostasis. Indeed, in vivo gain and loss of function experiments revealed that miRNA-206 and miRNA-21 were sufficient and required for atrophy program. In silico and in vivo approaches identified transcription factor YY1 and the translational initiator factor eIF4E3 as downstream targets of these miRNAs. Thus miRNAs are important for fine-tuning the atrophy program and their modulation can be a novel potential therapeutic approach to counteract muscle loss and weakness in catabolic conditions.

Cachectic skeletal muscle response to a novel bout of low-frequency stimulation.

While exercise benefits have been well documented in patients with chronic diseases, the mechanistic understanding of cachectic muscle's response to contraction is essentially unknown. We previously demonstrated that treadmill exercise training attenuates the initiation of cancer cachexia and the development of metabolic syndrome symptoms (Puppa MJ, White JP, Velazquez KT, Baltgalvis KA, Sato S, Baynes JW, Carson JA. J Cachexia Sarcopenia Muscle 3: 117-137, 2012). However, cachectic muscle's metabolic signaling response to a novel, acute bout of low-frequency contraction has not been determined. The purpose of this study was to determine whether severe cancer cachexia disrupts the acute contraction-induced response to low-frequency muscle contraction [low-frequency stimulation (LoFS)]. Metabolic gene expression and signaling was examined 3 h after a novel 30-min bout of contraction (10 Hz) in cachectic Apc(Min/+) (Min) and C57BL/6 (BL-6) mice. Pyrrolidine dithiocarbamate, a STAT/NF-κB inhibitor and free radical scavenger, was administered systemically to a subset of mice to determine whether this altered the muscle contraction response. Although glucose transporter-4 mRNA was decreased by cachexia, LoFS increased muscle glucose transporter-4 mRNA in both BL-6 and Min mice. LoFS also induced muscle peroxisome proliferator-activated receptor-γ and peroxisome proliferator-activated receptor-α coactivator-1 mRNA. However, in Min mice, LoFS was not able to induce muscle proliferator-activated receptor-α coactivator-1 targets nuclear respiratory factor-1 and mitochondrial transcription factor A mRNA. LoFS induced phosphorylated-S6 in BL-6 mice, but this induction was blocked by cachexia. Administration of pyrrolidine dithiocarbamate for 24 h rescued LoFS-induced phosphorylated-S6 in cachectic muscle. LoFS increased muscle phosphorylated-AMP-activated protein kinase and p38 in BL-6 and Min mice. These data demonstrate that cachexia alters the muscle metabolic response to acute LoFS, and combination therapies in concert with muscle contraction may be beneficial for improving muscle mass and function during cachexia.

Aberrant brain microRNA target and miRISC gene expression in the anx/anx anorexia mouse model.

The anorexia mouse model, anx/anx, carries a spontaneous mutation not yet identified and homozygous mutants are characterized by anorexia-cachexia, hyperactivity, and ataxia. In order to test if the microRNA function was altered in these mice, hypothalamus and cortex transcriptomes were evaluated and the data was analyzed taking into account the presence of microRNA target sites. Subsequent validation of the expression of a subset of miRISC coding genes and microRNA targets was performed by TaqMan real time PCR. In anx/anx hypothalamus we found that predicted microRNA targets were preferentially upregulated in a linearly dependent manner according to the number of microRNA target sites in each mRNA (p=10(-139)). Conversely, we observed that in anx/anx cortex mRNAs predicted to be targeted by microRNAs were preferentially downregulated (p<10(-74)), suggesting a de-regulation of genes targeted by microRNAs in two brain areas in anx/anx mice. A closer look to the mRNA transcriptome allowed us to identify upregulation of five miRISC genes, including Dgcr8 and Fmr1, and Ago2, which were later confirmed by real time PCR. The results suggest alteration of microRNA machinery expression in anx/anx mice and are consistent with its involvement in inflammatory/cancer-associated anorexia-cachexia. The data also support the previously reported link between microRNA machinery and ataxia. Further functional studies and the cloning of the anx gene should be pursued in order to elucidate the causality of microRNA machinery and microRNA target de-regulation, its relationship with the anx/anx phenotype and to propose this mouse as a model for microRNA research.

ICV vs. VMH injection of leptin: comparative effects on hypothalamic gene expression.

Leptin regulates feeding behavior and body weight by binding to its receptors localized in specific areas of the hypothalamus. Leptin injected twice daily for 4 days either into the right ventromedial hypothalamus (VMH) or into the right lateral cerebral ventricle (ICV) and using Real-Time Taqman RT-PCR, mRNA expression levels of selected genes in the arcuate nucleus-median eminence (ARC-ME) complex were quantitatively measured. Expression of selected genes from the ipsi- vs. contralateral VMH areas in rats injected with leptin into the VMH was also compared. VMH injections of leptin increased ARC-ME mRNAs of proopiomelanocortin (POMC), 27.3% (p<0.05); gamma-aminobutyric acid A receptor (GABRD), 89.3% (p<0.01); and thyrotropin-releasing hormone (TRH), 57.7% (p<0.01); and decreased janus kinase 2 (JAK2), 44.4% (p<0.001); suppressor of cytokine signaling 3 (SOCS3), 86.6% (p<0.001); signal transducer and activator of transcription 3 (STAT3), 46.8% (p<0.01); tyrosine hydroxylase (TH), 51.1% (p<0.001); prostaglandin E synthase (PTGES), 96.5% (p<0.001); tumor necrosis factor-alpha (TNF-alpha), 47% (p<0.01); and secretin, 55.4% (p<0.001). Only GABRD, 76.6% (p<0.01) and SCT, 64.9% (p<0.01) were up-regulated in the hypothalamic ARC-ME of rats with ICV leptin injections. VMH injections of leptin induced identical reductions in expression levels of CART, SOCS3, PTGES, and TNF-alpha in both VMH areas; except TH mRNA, whose expression was lowered ipsilaterally. Food intake, body and fat pad weights and serum insulin and leptin were also decreased in rats given leptin through VMH. This study suggests that leptin either unilateral exposure through VMH or bilateral exposure through ICV injections induces divergent ARC-ME gene profiles.

Hypothalamus transcriptome profile suggests an anorexia-cachexia syndrome in the anx/anx mouse model.

The anx/anx mouse displays poor appetite and lean appearance and is considered a good model for the study of anorexia nervosa. To identify new genes involved in feeding behavior and body weight regulation we performed an expression profiling in the hypothalamus of the anx/anx mice. Using commercial microarrays we detected 156 differentially expressed genes and validated 92 of those using TaqMan low-density arrays. The expression of a set of 87 candidate genes selected based on literature evidences was also quantified by TaqMan low-density arrays. Our results showed enrichment in deregulated genes involved in cell death, cell morphology, and cancer, as well as an alteration of several signaling circuits involved in energy balance including neuropeptide Y and melanocortin signaling. The expression profile along with the phenotype led us to conclude that anx/anx mice resemble the anorexia-cachexia syndrome typically observed in cancer, infection with human immunodeficiency virus or chronic diseases, rather than starvation, and that anx/anx mice could be considered a good model for the treatment and investigation of this condition.

MT1-MMP-deficient mice develop dwarfism, osteopenia, arthritis, and connective tissue disease due to inadequate collagen turnover.

MT1-MMP is a membrane-bound matrix metalloproteinase (MT-MMP) capable of mediating pericellular proteolysis of extracellular matrix components. MT1-MMP is therefore thought to be an important molecular tool for cellular remodeling of the surrounding matrix. To establish the biological role of this membrane proteinase we generated MT1-MMP-deficient mice by gene targeting. MT1-MMP deficiency causes craniofacial dysmorphism, arthritis, osteopenia, dwarfism, and fibrosis of soft tissues due to ablation of a collagenolytic activity that is essential for modeling of skeletal and extraskeletal connective tissues. Our findings demonstrate the pivotal function of MT1-MMP in connective tissue metabolism, and illustrate that modeling of the soft connective tissue matrix by resident cells is essential for the development and maintenance of the hard tissues of the skeleton.