ABSTRACT
Rest has long been considered beneficial to patient healing; however, remarkably, there are no evidence-based experimental models determining how it benefits disease outcomes. Here, we created an experimental rest model in mice that briefly extends the morning rest period. We found in 2 major cardiovascular disease conditions (cardiac hypertrophy, myocardial infarction) that imposing a short, extended period of morning rest each day limited cardiac remodeling compared with controls. Mechanistically, rest mitigates autonomic-mediated hemodynamic stress on the cardiovascular system, relaxes myofilament contractility, and attenuates cardiac remodeling genes, consistent with the benefits on cardiac structure and function. These same rest-responsive gene pathways underlie the pathophysiology of many major human cardiovascular conditions, as demonstrated by interrogating open-source transcriptomic data; thus, patients with other conditions may also benefit from a morning rest period in a similar manner. Our findings implicate rest as a key driver of physiology, creating a potentially new field - as broad and important as diet, sleep, or exercise - and provide a strong rationale for investigation of rest-based therapy for major clinical diseases.
Subject(s)
Myocardial Infarction , Ventricular Remodeling , Humans , Mice , Animals , Cardiomegaly/drug therapy , Heart , MyofibrilsABSTRACT
Alcohol use is a contributor in the premature deaths of approximately 3 million people annually. Among the risk factors for alcohol misuse is circadian rhythm disruption; however, this connection remains poorly understood. Inhibition of the circadian nuclear receptor REV-ERBα is known to disrupt molecular feedback loops integral to daily oscillations, and impact diurnal fluctuations in the expression of proteins required for reward-related neurotransmission. However, the role of REV-ERBα in alcohol and substance use-related phenotypes is unknown. Herein, we used a Rev-erbα knockout mouse line and ethanol two-bottle choice preference testing to show that disruption of Rev-erbα reduces ethanol preference in male and female mice. Rev-erbα null mice showed the lowest ethanol preference in a two-bottle choice test across all genotypes, whereas there were no ethanol preference differences between heterozygotes and wildtypes. In a separate experiment, alcohol-consuming wildtype C57Bl/6N mice were administered the REV-ERBα/ß inhibitor SR8278 (25 mg/kg or 50 mg/kg) for 7 days and alcohol preference was evaluated daily. No differences in alcohol preference were observed between the treatment and vehicle groups. Our data provides evidence that genetic variation in REV-ERBα may contribute to differences in alcohol drinking.
Subject(s)
Circadian Rhythm , Nuclear Receptor Subfamily 1, Group D, Member 1 , Alcohol Drinking/genetics , Animals , Circadian Rhythm/physiology , Ethanol , Female , Humans , Male , Mice , Mice, Knockout , Nuclear Receptor Subfamily 1, Group D, Member 1/genetics , Nuclear Receptor Subfamily 1, Group D, Member 1/metabolismABSTRACT
Shift work is associated with increased alcohol drinking, more so in males than females, and is thought to be a coping mechanism for disrupted sleep cycles. However, little is presently known about the causal influence of circadian rhythm disruptions on sex differences in alcohol consumption. In this study, we disrupted circadian rhythms in female and male mice using both environmental (i.e., shifting diurnal cycles) and genetic (i.e., ClockΔ19/Δ19 mutation) manipulations, and measured changes in alcohol consumption and preference using a two-bottle choice paradigm. Alcohol consumption and preference, as well as food and water consumption, total caloric intake, and weight were assessed in adult female and male ClockΔ19/Δ19 mutant mice or wild-type (WT) litter-mates, housed under a 12-hour:12-hour light:dark (L:D) cycle or a shortened 10-hour:10-hour L:D cycle. Female WT mice (under both light cycles) increased their alcohol consumption and preference over time, a pattern not observed in male WT mice. Compared to WT mice, ClockΔ19/Δ19 mice displayed increased alcohol consumption and preference. Sex differences were not apparent in ClockΔ19/Δ19 mice, with or without shifting diurnal cycles. In conclusion, sex differences in alcohol consumption patterns are evident and increase with prolonged access to alcohol. Disrupting circadian rhythms by mutating the Clock gene greatly increases alcohol consumption and abolishes sex differences present in WT animals.
Subject(s)
CLOCK Proteins , Circadian Rhythm , Alcohol Drinking/genetics , Animals , CLOCK Proteins/genetics , Circadian Rhythm/genetics , Female , Genotype , Male , Mice , MutationABSTRACT
Cardiac function is highly reliant on mitochondrial oxidative metabolism and quality control. The circadian Clock gene is critically linked to vital physiological processes including mitochondrial fission, fusion and bioenergetics; however, little is known of how the Clock gene regulates these vital processes in the heart. Herein, we identified a putative circadian CLOCK-mitochondrial interactome that gates an adaptive survival response during myocardial ischemia. We show by transcriptome and gene ontology mapping in CLOCK Δ19/Δ19 mouse that Clock transcriptionally coordinates the efficient removal of damaged mitochondria during myocardial ischemia by directly controlling transcription of genes required for mitochondrial fission, fusion and macroautophagy/autophagy. Loss of Clock gene activity impaired mitochondrial turnover resulting in the accumulation of damaged reactive oxygen species (ROS)-producing mitochondria from impaired mitophagy. This coincided with ultrastructural defects to mitochondria and impaired cardiac function. Interestingly, wild type CLOCK but not mutations of CLOCK defective for E-Box binding or interaction with its cognate partner ARNTL/BMAL-1 suppressed mitochondrial damage and cell death during acute hypoxia. Interestingly, the autophagy defect and accumulation of damaged mitochondria in CLOCK-deficient cardiac myocytes were abrogated by restoring autophagy/mitophagy. Inhibition of autophagy by ATG7 knockdown abrogated the cytoprotective effects of CLOCK. Collectively, our results demonstrate that CLOCK regulates an adaptive stress response critical for cell survival by transcriptionally coordinating mitochondrial quality control mechanisms in cardiac myocytes. Interdictions that restore CLOCK activity may prove beneficial in reducing cardiac injury in individuals with disrupted circadian CLOCK.Abbreviations: ARNTL/BMAL1: aryl hydrocarbon receptor nuclear translocator-like; ATG14: autophagy related 14; ATG7: autophagy related 7; ATP: adenosine triphosphate; BCA: bovine serum albumin; BECN1: beclin 1, autophagy related; bHLH: basic helix- loop-helix; CLOCK: circadian locomotor output cycles kaput; CMV: cytomegalovirus; COQ5: coenzyme Q5 methyltransferase; CQ: chloroquine; CRY1: cryptochrome 1 (photolyase-like); DNM1L/DRP1: dynamin 1-like; EF: ejection fraction; EM: electron microscopy; FS: fractional shortening; GFP: green fluorescent protein; HPX: hypoxia; i.p.: intraperitoneal; I-R: ischemia-reperfusion; LAD: left anterior descending; LVIDd: left ventricular internal diameter diastolic; LVIDs: left ventricular internal diameter systolic; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MFN2: mitofusin 2; MI: myocardial infarction; mPTP: mitochondrial permeability transition pore; NDUFA4: Ndufa4, mitochondrial complex associated; NDUFA8: NADH: ubiquinone oxidoreductase subunit A8; NMX: normoxia; OCR: oxygen consumption rate; OPA1: OPA1, mitochondrial dynamin like GTPase; OXPHOS: oxidative phosphorylation; PBS: phosphate-buffered saline; PER1: period circadian clock 1; PPARGC1A/PGC-1α: peroxisome proliferative activated receptor, gamma, coactivator 1 alpha; qPCR: quantitative real-time PCR; RAB7A: RAB7, member RAS oncogene family; ROS: reactive oxygen species; RT: room temperature; shRNA: short hairpin RNA; siRNA: small interfering RNA; TFAM: transcription factor A, mitochondrial; TFEB: transcription factor EB; TMRM: tetra-methylrhodamine methyl ester perchlorate; WT: wild -type; ZT: zeitgeber time.
Subject(s)
CLOCK Proteins/physiology , Cell Survival , Ischemia/metabolism , Mitophagy , Myocytes, Cardiac/physiology , Animals , CLOCK Proteins/metabolism , Cell Survival/physiology , Ischemia/physiopathology , Male , Membrane Potential, Mitochondrial , Mice , Mice, Inbred C57BL , Mitochondria, Heart/metabolism , Mitophagy/physiology , Myocytes, Cardiac/metabolismABSTRACT
Myocardial infarction (MI) leading to heart failure (HF) is a major cause of death worldwide. Previous studies revealed that the circadian system markedly impacts cardiac repair post-MI, and that light is an important environmental factor modulating the circadian influence over healing. Recent studies suggest that gut physiology also affects the circadian system, but how it contributes to cardiac repair post-MI and in HF is not well understood. To address this question, we first used a murine coronary artery ligation MI model to reveal that an intact gut microbiome is important for cardiac repair. Specifically, gut microbiome disruption impairs normal inflammatory responses in infarcted myocardium, elevates adverse cardiac gene biomarkers, and leads to worse HF outcomes. Conversely, reconstituting the microbiome post-MI in mice with prior gut microbiome disruption improves healing, consistent with the notion that normal gut physiology contributes to cardiac repair. To investigate a role for the circadian system, we initially utilized circadian mutant Clock∆19/∆19 mice, revealing that a functional circadian mechanism is necessary for gut microbiome benefits on post-MI cardiac repair and HF. Finally, we demonstrate that circadian-mediated gut responses that benefit cardiac repair can be conferred by time-restricted feeding, as wake time feeding of MI mice improves HF outcomes, but these benefits are not observed in MI mice fed during their sleep time. In summary, gut physiology is important for cardiac repair, and the circadian system influences the beneficial gut responses to improve post-MI and HF outcomes.
Subject(s)
Circadian Rhythm/physiology , Gastrointestinal Microbiome , Heart Failure/microbiology , Heart Failure/physiopathology , Animals , CLOCK Proteins/metabolism , Hemodynamics , Inflammation/pathology , Leukocytes/pathology , Male , Metabolome , Mice, Inbred C57BL , Myocardial Infarction/microbiology , Myocardial Infarction/physiopathology , Ventricular Remodeling/physiologyABSTRACT
Reperfusion of patients after myocardial infarction (heart attack) triggers cardiac inflammation that leads to infarct expansion and heart failure (HF). We previously showed that the circadian mechanism is a critical regulator of reperfusion injury. However, whether pharmacological targeting using circadian medicine limits reperfusion injury and protects against HF is unknown. Here, we show that short-term targeting of the circadian driver REV-ERB with SR9009 benefits long-term cardiac repair post-myocardial ischemia reperfusion in mice. Gain and loss of function studies demonstrate specificity of targeting REV-ERB in mice. Treatment for just one day abates the cardiac NLRP3 inflammasome, decreasing immunocyte recruitment, and thereby allowing the vulnerable infarct to heal. Therapy is given in vivo, after reperfusion, and promotes efficient repair. This study presents downregulation of the cardiac inflammasome in fibroblasts as a cellular target of SR9009, inviting more targeted therapeutic investigations in the future.
Subject(s)
Heart Failure/etiology , Heart Failure/metabolism , Inflammasomes/metabolism , Myocardial Ischemia/complications , Myocardial Ischemia/metabolism , Myocardial Reperfusion , Pyrrolidines/pharmacology , Thiophenes/pharmacology , Animals , Biomarkers , Biopsy , Heart Failure/pathology , Heart Failure/prevention & control , Immunohistochemistry , Mice , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Nuclear Receptor Subfamily 1, Group D, Member 1/geneticsABSTRACT
In this study we investigated the role of the circadian mechanism on cognition-relevant brain regions and neurobiological impairments associated with heart failure (HF), using murine models. We found that the circadian mechanism is an important regulator of healthy cognitive system neurobiology. Normal Clock∆19/∆19 mice had neurons with smaller apical dendrite trees in the medial prefrontal cortex (mPFC), and hippocampus, showed impaired visual-spatial memory, and exhibited lower cerebrovascular myogenic tone, versus wild types (WT). We then used the left anterior descending coronary artery ligation model to investigate adaptations in response to HF. Intriguingly, adaptations to neuron morphology, memory, and cerebrovascular tone occurred in differing magnitude and direction between Clock∆19/∆19 and WT mice, ultimately converging in HF. To investigate this dichotomous response, we performed microarrays and found genes crucial for growth and stress pathways that were altered in Clock∆19/∆19 mPFC and hippocampus. Thus these data demonstrate for the first time that (i) the circadian mechanism plays a role in neuron morphology and function; (ii) there are changes in neuron morphology and function in HF; (iii) CLOCK influences neurobiological gene adaptations to HF at a cellular level. These findings have clinical relevance as patients with HF often present with concurrent neurocognitive impairments. There is no cure for HF, and new understanding is needed to reduce morbidity and improve the quality of life for HF patients.
Subject(s)
CLOCK Proteins/genetics , Circadian Rhythm/genetics , Heart Failure/genetics , Neurons/pathology , Acclimatization/genetics , Acclimatization/physiology , Animals , Dendrites/metabolism , Dendrites/pathology , Disease Models, Animal , Heart Failure/pathology , Hippocampus/pathology , Humans , Memory/physiology , Mice , Neurons/metabolism , Prefrontal Cortex/metabolism , Prefrontal Cortex/pathology , Signal Transduction/geneticsABSTRACT
OBJECTIVES: Fingerprints have so far been used for determining the basis of certain malignant diseases, with positive outcomes. Considering the high rates of cancer-related mortality in Iran, this study was conducted for the purpose of examining the dermatoglyphic pattern of fingers in patients with gynecological cancers as compared to healthy people. STUDY DESIGN: The present study was conducted on 151 women with gynecological cancers as the case group and 152 healthy women with no history of such cancers as control group. The dematographic details of participants from both control and case groups were collected using a checklist, and the pattern of their fingerprints was prepared and examined. The data were analyzed for their significance using chi-square test and t- test. Odds ratio with 95% confidence intervals were calculated. RESULTS: Dermatoglyphic analysis showed that arch and loop patterns significantly changed in cases group as compared to control. However, the odds ratio suggested that loop pattern in 6 or more fingers might be a risk factor for developing gynecological cancers. CONCLUSION: Our results showed that there is an association between fingerprint patterns and gynecological cancers and so, dermatoglyphic analysis may aid in the early diagnosis of these cancers.
Subject(s)
Dermatoglyphics , Early Detection of Cancer , Genital Neoplasms, Female/diagnosis , Adult , Case-Control Studies , Checklist , Developing Countries , Female , Fingers , Genital Neoplasms, Female/epidemiology , Genital Neoplasms, Female/ethnology , Humans , Hydatidiform Mole/diagnosis , Hydatidiform Mole/epidemiology , Hydatidiform Mole/ethnology , Incidence , Iran/epidemiology , Middle Aged , Odds Ratio , Ovarian Neoplasms/diagnosis , Ovarian Neoplasms/epidemiology , Ovarian Neoplasms/ethnology , Placenta Diseases/diagnosis , Placenta Diseases/epidemiology , Placenta Diseases/ethnology , Pregnancy , Risk Factors , Uterine Neoplasms/diagnosis , Uterine Neoplasms/epidemiologyABSTRACT
BACKGROUND: Dead islets replaced with viable islets are a promising offer to restore normal insulin production to a person with diabetes. The main reason for establishing a new islet source for transplantation is the insufficiency of human donor pancreas while using xenogeneic islets perhaps assists this problem. The expression of PDX1 is essential for the pancreas expansion. In mature ß-cells, PDX1 has several critical roles such as glucose sensing, insulin synthesis, and insulin secretion. In this study, we aimed to evaluate the expression of pancreatic duodenal homeobox-1 (PDX1) in treated caprine islets in culture and to assess the protective effects of antioxidant factors on the PDX1 gene in cultured caprine islets. MATERIALS AND METHODS: Purified islets were treated with serum-free, serum, IBMX, tocopherol, or IBMX and tocopherol media. Quantitative polymerase chain reaction and Western blotting were carried out to compare the expression levels of PDX1 in treated purified islets cultured with different media. RESULTS: Islets treated with IBMX/tocopherol exhibited the highest fold change in the relative expression of PDX1 on day 5 post-treatment (relative expression: 6.80±2.08), whereas serum-treated islets showed the lowest fold changes in PDX1 expression on day 5 post-treatment (0.67±0.36), as compared with the expression on day 1 post-treatment. Insulin production and viability tests of purified islets showed superiority of islet at supplemented serum-free media with IBMX/tocopherol compared to other cultures (53.875%±1.59%). CONCLUSIONS: Our results indicated that supplemented serum-free medium with tocopherol and IBMX enhances viability and PDX1 gene expression compared to serum-added and serum-free media.
Subject(s)
Goats/genetics , Goats/physiology , Homeodomain Proteins/genetics , Homeodomain Proteins/physiology , Islets of Langerhans/physiology , Trans-Activators/genetics , Trans-Activators/physiology , 1-Methyl-3-isobutylxanthine/pharmacology , Animals , Antioxidants/pharmacology , Cell Survival/drug effects , Cell Survival/genetics , Cell Survival/physiology , Culture Media , Culture Media, Serum-Free , Gene Expression/drug effects , Genes, Homeobox , In Vitro Techniques , Insulin/biosynthesis , Islets of Langerhans/cytology , Islets of Langerhans/drug effects , Male , Tocopherols/pharmacologyABSTRACT
Fanconi Anemia (FA) is an autosomal recessive syndrome characterized by congenital abnormalities, progressive bone marrow failure and Fanconi anemia complementation group A (FANCA) is also a potential breast and ovarian cancer susceptibility gene. A novel allele with tandem duplication of 13 base pair sequence in promoter region was identified. To investigate whether the 13 base pair sequence of tandem duplication in promoter region of the FANCA gene is of high penetrance in patients with breast cancer and to determine if the presence of the duplicated allele was associated with an altered risk of breast cancer, the present study screened DNA in blood samples from 304 breast cancer patients and 295 normal individuals as controls. The duplication allele had a frequency of 35.4 and 21.2% in patients with breast cancer and normal controls, respectively. There was a significant increase in the frequency of the duplication allele in patients with familial breast cancer compared with controls (45.1%, P=0.001). Furthermore, the estimated risk of breast cancer in individuals with a homozygote [odds ratio (OR), 4.093; 95% confidence intervals (CI), 1.9578.561] or heterozygote duplicated genotype (OR, 3.315; 95% CI, 1.9965.506) was higher compared with the corresponding normal homozygote genotype. In conclusion, the present study indicated that the higher the frequency of the duplicated allele, the higher the risk of breast cancer. To the best of our knowledge, the present study is the first to report FANCA gene duplication in patients with breast cancer.
Subject(s)
Alleles , Breast Neoplasms/epidemiology , Breast Neoplasms/genetics , Fanconi Anemia Complementation Group A Protein/genetics , Genetic Predisposition to Disease , Genetic Variation , Adult , Aged , Case-Control Studies , Female , Gene Duplication , Genotype , Humans , Iran/epidemiology , Middle Aged , Odds Ratio , Population Surveillance , Promoter Regions, Genetic , Risk FactorsABSTRACT
The final stage of cell division (mitosis), involves the compaction of the duplicated genome into chromatid pairs. Each pair is captured by microtubules emanating from opposite spindle poles, aligned at the metaphase plate, and then faithfully segregated to form two identical daughter cells. Chromatids that are not correctly attached to the spindle are detected by the constitutively active spindle assembly checkpoint (SAC). Any stress that prevents correct bipolar spindle attachment, blocks the satisfaction of the SAC, and induces a prolonged mitotic arrest, providing the cell time to obtain attachment and complete segregation correctly. Unfortunately, during mitosis repairing damage is not generally possible due to the compaction of DNA into chromosomes, and subsequent suppression of gene transcription and translation. Therefore, in the presence of significant damage cell death is instigated to ensure that genomic stability is maintained. While most stresses lead to an arrest in mitosis, some promote premature mitotic exit, allowing cells to bypass mitotic cell death. This mini-review will focus on the effects and outcomes that common stresses have on mitosis, and how this impacts on the efficacy of mitotic chemotherapies.
ABSTRACT
Enteroendocrine cells are the largest population of hormone-producing cells in the body and play important roles in many aspects of body functions. The enteroendocrine cell population is divided into different subpopulations that secrete different hormones and peptides. Characterization of each subpopulation is particularly useful for analyzing the cellular mechanisms responsible for specific cell types. Therefore, the necessity of a pure cell line for a specific study purpose was the important motivation for the separation of cell lines for each subpopulation of enteroendocrine cells. The present research introduces a method for the isolation of L-cells, one of the important subpopulations of enteroendocrine cells. The antibiotic selection method was conducted in order to isolate the L-cells from a heterogonous population of intestinal cell line. In this method, a neomycin resistance gene (as selected marker) was expressed under the control of a specific promoter of L-cells. After transfection of manipulated plasmid, only the cells which determine the specific promoter and express neomycin resistance protein would be able to survive under Geneticin antibiotic treatment condition. In order to confirm that the isolated cells were L-cells, reverse transcriptase polymerase chain reaction (PCR) and quantitative PCR assays were performed. Based on the results, the isolated cells were pure L-cells that could be able to express specific mRNA of L-cells efficiently. This technique provides a unique method for the isolation and purification of any cell line. The purified isolated L-cells by this method can be used for future studies and for analyzing cellular mechanisms that involve L-cells' functions.
Subject(s)
Anti-Bacterial Agents/pharmacology , Cell Separation/methods , Intestines/cytology , Animals , Cell Line, Tumor , Enteroendocrine Cells/cytology , Enteroendocrine Cells/drug effects , Gentamicins/pharmacology , Glucagon-Like Peptide 1/genetics , Mice , Plasmids/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , TransfectionABSTRACT
Poorly controlled diabetes mellitus can result in serious complications. Gene therapy is increasingly being considered as an alternative approach to treat diabetes, because of its ability to induce physiological insulin secretion and it allows patients to escape insulin injections. The properties of gut K and L-cells, including glucose sensitivity, the ability to process insulin and a regulated secretion pathway support their use as surrogate ß-cells. Previous in vitro studies have provided sufficient evidence supporting the use of these cells for gene therapy studies. Therefore, we examined the ability of K and L-cells to produce insulin in diabetic mice. Chitosan nanoparticles were used to transfer the insulin gene into intestinal cells via oral administration. The efficiency of chitosan as a gene vehicle was investigated through the use of reporter gene. Insulin mRNA and protein expression levels were measured by RT-PCR and ELISA, respectively. Blood glucose testing revealed that this treatment reduced glucose levels in diabetic mice. The decrease in blood glucose level in the first week of treatment was greater in mice with K-cell specific insulin expression compared with mice with L-cell-specific insulin expression. These results indicate that inducing insulin secretion in K-cells conferred a quicker response to gene therapy.
Subject(s)
Diabetes Mellitus/genetics , Genetic Engineering , Insulin/genetics , Intestines/cytology , Animals , Blood Glucose/genetics , Chitosan/administration & dosage , Chitosan/chemistry , Diabetes Mellitus/blood , Diabetes Mellitus/pathology , Enteroendocrine Cells/metabolism , Gene Transfer Techniques , Humans , Insulin/metabolism , Insulin Secretion , Intestinal Mucosa/metabolism , Mice , Mice, Inbred NOD , Nanoparticles/administration & dosage , Nanoparticles/chemistryABSTRACT
Genetic mutations in premalignant breast lesions may have a role in malignancy progression or influence the behavior of subsequent disease. A point mutation in estrogen receptor-α (ER-α) as A908G (Lys303âArg) was originally involved to hypersensitive to estrogen breast hyperplasia. We detected this mutation among Iranian women with invasive breast cancer. A population-based case-control study was conducted in 150 newly diagnosed invasive breast cancer and 147 healthy control individuals controls to screen for presence of the ER-α A908G mutation by using single-strand conformation polymorphism (SSCP) analysis and 33Pcycle DNA sequencing. We detected the 10.7% ER-α A908G mutation in the form of heterozygote genotype only among cancer patients (χ(2)=22.752, P=0.00). The allelic frequency of mutant allele AGG in codon 303 was significantly (χ(2)=29.709, P=0.001) higher in patients with the family history of breast cancer (28.9%) than those without the family history of breast cancer (1.9%). Our data suggest that ER-α codon 303 mutation is correlated with various aspects of breast cancer in Iran. ER-α genotype might represent a surrogate marker for predicting breast cancer developing later in life.
ABSTRACT
BACKGROUND: Gene therapy could provide an effective treatment of diabetes. Previous studies have investigated the potential for several cell and tissue types to produce mature and active insulin. Gut K and L-cells could be potential candidate hosts for gene therapy because of their special features. RESULTS: In this study, we isolated gut K and L-cells to compare the potential of both cell types to produce insulin when exposed to similar conditions. The isolated pure K and L-cells were transfected with recombinant plasmids encoding insulin and with specific promoters for K or L-cells. Insulin expression was studied in response to glucose or meat hydrolysate. We found that glucose and meat hydrolysate efficiently induced insulin secretion from K and L-cells. However, the effects of meat hydrolysate on insulin secretion were more potent in both cells compared with glucose. Results of enzyme-linked immunosorbent assays showed that L-cells secreted more insulin compared with K-cells regardless of the stimulator, although this difference was not statistically significant. CONCLUSION: The responses of K and L-cells to stimulation with glucose or meat hydrolysate were generally comparable. Therefore, both K and L-cells show similar potential to be used as surrogate cells for insulin gene expression in vitro. The potential use of these cells for diabetic gene therapy warrants further investigation.
Subject(s)
Insulin/genetics , Insulin/metabolism , Intestines/cytology , Animals , Cell Separation , Gene Expression , Genetic Engineering , Glucose/metabolism , Insulin Secretion , Intestinal Mucosa/metabolism , L Cells , MiceABSTRACT
BACKGROUND: Diabetes mellitus is a complicated disease with a pathophysiology that includes hyperinsulinemia, hyperglycemia and other metabolic impairments leading to many clinical complications. It is necessary to develop appropriate treatments to manage the disease and reduce possible acute and chronic side effects. The advent of gene therapy has generated excitement in the medical world for the possible application of gene therapy in the treatment of diabetes. The glucagon-like peptide-1 (GLP-1) promoter, which is recognised by gut L-cells, is an appealing candidate for gene therapy purposes. The specific properties of L-cells suggest that L-cells and the GLP-1 promoter would be useful for diabetes therapy approaches. RESULTS: In this study, L-cells were isolated from a primary intestinal cell line to create suitable target cells for insulin expression studies. The isolated cells displayed L-cell properties and were therefore used as an L-cell surrogate. Next, the isolated L-cells were transfected with the recombinant plasmid consisting of an insulin gene located downstream of the GLP-1 promoter. The secretion tests revealed that an increase in glucose concentration from 5 mM to 25 mM induced insulin gene expression in the L-cells by 2.7-fold. Furthermore, L-cells quickly responded to the glucose stimulation; the amount of insulin protein increased 2-fold in the first 30 minutes and then reached a plateau after 90 minutes. CONCLUSION: Our data showed that L-cells efficiently produced the mature insulin protein. In addition, the insulin protein secretion was positively regulated with glucose induction. In conclusion, GLP-1 promoter and L-cell could be potential candidates for diabetes gene therapy agents.
Subject(s)
Diabetes Mellitus/drug therapy , Epithelial Cells/metabolism , Genetic Engineering/methods , Glucagon-Like Peptide 1 , Glucose/pharmacology , Insulin , Molecular Targeted Therapy , Plasmids/genetics , Animals , Cell Line, Tumor , Diabetes Mellitus/metabolism , Dose-Response Relationship, Drug , Epithelial Cells/cytology , Epithelial Cells/drug effects , Gene Expression , Genetic Therapy/methods , Glucagon/metabolism , Glucagon-Like Peptide 1/genetics , Glucagon-Like Peptide 1/metabolism , Glucose/metabolism , Humans , Insulin/metabolism , Insulin Secretion , Intestinal Mucosa/cytology , Intestinal Mucosa/metabolism , Intestines/cytology , Mice , Plasmids/chemistry , Promoter Regions, Genetic , TransfectionABSTRACT
Identification of casual mutations in Hereditary Multiple Exostoses (HME) is important because of similar conditions in which multiple exostoses occur. Therefore mutation analysis can help to confirm the clinical diagnosis and to improve the management of therapy. HME is an inherited disorder of bone growth. HME can be referred to by various names such as Heredity Multiple Exostoses, Hereditary Multiple Osteochondromata, Multiple Carthaginous Exostoses, etc. People who have HME grow exostoses, or bony bumps, on their bones which can vary in size, location and number depending on the individual. HME is inherited in an autosomal dominant manner with an estimated prevalence of 1/50,000 in western countries. At least three loci (EXT1, EXT2 and EXT3) thought to be involved in this skeletal disease. Approximately 90% of affected families possess mutations in the coding regions of EXT1 and EXT2 genes and the majority of these mutations cause loss of function. EXT1 and EXT2 genes encode related members of a putative tumor suppressor family. In this first report from Iran we identified a frame shift mutation (1100-1101 insA) in exon 3 of EXT1 gene in a family being suspicious of HME. This mutation leads to a premature stop codon and previously not described. Additionally, we have found an unreported silent mutation in the exon six of EXT1 gene with uncertain significance.