Decreased basal chloride secretion and altered cystic fibrosis transmembrane conductance regulatory protein, Villin, GLUT5 protein expression in jejunum from leptin-deficient mice

Exercise Training Prevents the Loss of Wall Thickness and Lowers Expression of Alzheimer's Related Proteins in 3xTg Mouse Jejunum

Growing evidence has demonstrated the benefits of regular exercise on cardiovascular, neural, and cognitive function in humans with Alzheimer's disease (AD). However, the consequences of AD on gastrointestinal morphology and the effects of regular exercise, which plays an important role against the development of certain gastrointestinal-related diseases, are still poorly understood. Therefore, to assess the changes in intestinal structure in a mouse model of AD and the impact of exercise, 2-month-old 3xTg-AD male mice were subjected to treadmill running 5 days per week for a period of 5 months. Jejunum from 3xTg-AD mice analyzed by histochemical methods revealed significant alterations in morphology. Compared to age-matched wild-type (WT) mice, villi length and crypt depth were increased, and collagen content of jejunum was elevated in 3xTg-AD mice. Jejunum wall dimensions, expressed as total wall thickness, outer longitudinal thickness, and inner circular thickness were decreased in 3xTg-AD compared to WT. Smooth muscle actin expression in jejunal wall was decreased in 3xTg-AD. Most of these aberrations were improved with exercise. Western blot expression of cyclin dependent kinase 5 (CDK5, involved in neural cell death and hyperphosphorylation of tau), was elevated in 3xTg-AD jejunum. This was associated with a 4-fold increase in tau5 expression. Exercise prevented the increase in expression of CDK5 and tau5. Expression of caspase 3 (an apoptotic marker) was elevated in 3xTg-AD jejunum and exercise prevented this. The results of our study indicate that the abnormalities in jejunum of the 3xTg mouse model of AD were prevented with exercise training.

Inhibition of intestinal villus cell Na/K-ATPase mediates altered glucose and NaCl absorption in obesity-associated diabetes and hypertension

During obesity, diabetes and hypertension inevitably coexist and cause innumerable health disparities. In the obesity, diabetes, and hypertension triad (ODHT), deregulation of glucose and NaCl homeostasis, respectively, causes diabetes and hypertension. In the mammalian intestine, glucose is primarily absorbed by Na-glucose cotransport 1 (SGLT1) and coupled NaCl by the dual operation of Na-H exchange 3 (NHE3) and Cl-HCO3 [down-regulated in adenoma (DRA) or putative anion transporter 1 (PAT1)] exchange in the brush border membrane (BBM) of villus cells. The basolateral membrane (BLM) Na/K-ATPase provides the favorable transcellular Na gradient for BBM SGLT1 and NHE3. How these multiple, distinct transport processes may be affected in ODHT is unclear. Here, we show the novel and broad regulation by Na/K-ATPase of glucose and NaCl absorption in ODHT in multiple species (mice, rats, and humans). In vivo, during obesity inhibition of villus-cell BLM, Na/K-ATPase led to compensatory stimulation of BBM SGLT1 and DRA or PAT1, whereas NHE3 was unaffected. Supporting this new cellular adaptive mechanism, direct silencing of BLM Na/K-ATPase in intestinal epithelial cells resulted in selective stimulation of BBM SGLT1 and DRA or PAT1 but not NHE3. These changes will lead to an increase in glucose absorption, maintenance of traditional coupled NaCl absorption, and a de novo increase in NaCl absorption from the novel coupling of stimulated SGLT1 with DRA or PAT1. Thus, these novel observations provide the pathophysiologic basis for the deregulation of glucose and NaCl homeostasis of diabetes and hypertension, respectively, during obesity. These observations may lead to more efficacious treatment for obesity-associated diabetes and hypertension.-Palaniappan, B., Arthur, S., Sundaram, V. L., Butts, M., Sundaram, S., Mani, K., Singh, S., Nepal, N., Sundaram, U. Inhibition of intestinal villus cell Na/K-ATPase mediates altered glucose and NaCl absorption in obesity-associated diabetes and hypertension.

Genistein diet improves body weight, serum glucose and triglyceride levels in both male and female ob/ob mice

PURPOSE

Diabetic obesity in the leptin-deficient ob/ob mouse is associated with weight gain, and hyperglycemia, along with hyperinsulinemia. We have previously examined the effects of genistein (a naturally occurring isoflavone found in soy) on metabolic disturbances in the ob/ob mouse and demonstrated beneficial effects of genistein (600 mg genistein/kg diet, for 4-weeks) on T₃ production and corticosterone status. The goal of this study was to examine whether dietary genistein could prevent, or at least lessen, the typical phenotype in this murine model of diabetic-obesity, and to assess potential sex-differences.

PATIENTS AND METHODS

The ob/ob mice (male and female) aged 4-5 weeks were randomly assigned to one of two diets for a period of 4-weeks: standard rodent diet, or genistein-containing diet (600 mg genistein/kg diet). Comparisons were made to a lean control group.

RESULTS

Genistein diet significantly reduced body weight by 12% in females and 9% in males. Genistein significantly lowered serum glucose levels by 18% in females and 43% in males, yet had no effect on serum insulin. Genistein diet significantly lowered serum triglyceride levels in both ob/ob male and female mice returning them to lean levels. In females only, genistein significantly reduced serum pancreatic polypeptide levels by 56% and increased serum GIP levels 2.3-fold. Genistein had sex-dependent effects on hepatic steatosis: in females, genistein further increased the % fat area and the fat droplet diameter 2.6-fold, along with additionally increasing hepatic TBARS.

CONCLUSION

The results from this study indicate interesting beneficial effects of genistein diet for both male and female ob/ob mice.

Consuming Genistein Improves Survival Rates in the Absence of Laxative in ΔF508-CF Female Mice

Genistein is a naturally occurring isoflavone found in soy. Genistein has been shown to increase the open probability of the most common cystic fibrosis (CF) disease-associated mutation, ∆F508-CFTR. Mice homozygous for the ∆F508 mutation are characterized with severe intestinal disease and require constant laxative treatment for survival. This pathology mimics the intestinal obstruction (meconium ileus) seen in some cystic fibrosis patients. This study tested whether dietary supplementation with genistein would reduce the dependence of the ∆F508 CF mouse model on laxatives for survival, thereby improving mortality rates. At weaning (21 days), homozygous ∆F508 mice were maintained on one of three diet regimens for a period of up to 65 days: normal diet, normal diet plus colyte, or genistein diet. Survival rates for males were as follows: standard diet (38%, n = 21), standard diet plus colyte (83%, n = 42) and genistein diet (60%, n = 15). Survival rates for females were as follows: standard diet (47%, n = 19), standard diet plus colyte (71%, n = 38), and genistein diet (87%, n = 15). Average weight of male mice fed genistein diet increased by ~2.5 g more (p = 0.006) compared to those with colyte treatment. Genistein diet did not change final body weight of females. Expression of intestinal SGLT-1 increased 2-fold (p = 0.0005) with genistein diet in females (no change in males, p = 0.722). Expression of GLUT2 and GLUT5 was comparable between all diet groups. Genistein diet reduced the number of goblet cells per micrometer of crypt depth in female (p = 0.0483), yet was without effect in males (p = 0.7267). The results from this study demonstrate that supplementation of diet with genistein for ~45 days increases the survival rate of female ∆F508-CF mice (precluding the requirement for laxatives), and genistein only improves weight gain in males.

Circulating brain-derived neurotrophic factor, leptin, neuropeptide Y, and their clinical correlates in cystic fibrosis: a cross-sectional study

INTRODUCTION

Cystic fibrosis (CF) involves chronic inflammation and decreased pulmonary function, which increase caloric demand. Yet, sufficient energy provision is hindered by reduced appetite and fat malabsorption. Brain-derived neurotrophic factor (BDNF), leptin, and neuropeptide Y (NPY) belong to energy balance-regulating factors. We aimed to assess their concentrations in CF patients in order to search for potential clinical correlates.

MATERIAL AND METHODS

This was an exploratory, cross-sectional study. Patients' weight and height Z-scores, forced expiratory volume in 1 s (FEV1%), exocrine pancreatic status (fecal elastase-1), genotypes, and other characteristics were assessed. Serum concentrations of BDNF, leptin, NPY, IL-6, and TNF-α were measured using ELISA.

RESULTS

The study enrolled 56 patients, of whom 29 (52%) were female and 17 (30%) were younger than 16 years. Median (1st-3rd quartile) mass Z-score was -0.85 (-1.56-(-0.36)); median FEV1 was 70.5% (45.0-89.5); 48 (86%) patients had exocrine pancreatic insufficiency and 8 (14%) diabetes. Overall, median concentrations were: BDNF: 33.91 ng/ml (26.40-40.43), leptin: 12.05 ng/ml (8.93-17.77), NPY: 2.86 ng/ml (1.75-4.42). None of these factors correlated with mass Z-score, FEV1%, IL-6 or TNF-α. Leptin and NPY correlated negatively (ρ = -0.62, p = 3 × 10-7); BDNF/NPY ratio was associated with leptin (ρ = 0.54, p = 2 × 10-5), BDNF/leptin ratio correlated with NPY (ρ = 0.60, p = 1 × 10-6). In a multivariable regression analysis NPY was weakly, but independently, associated with FEV1%, and leptin with age.

CONCLUSIONS

BDNF and leptin were not associated with weight Z-score or FEV1%. Serum NPY concentrations seemed to be lower in CF patients with reduced pulmonary function independently of malnutrition and inflammation.

Genistein diet does not modify crypt morphology in the ob/ob mouse jejunum: a comparison of cryostat and clearing techniques

INTRODUCTION

Diabetes is commonly associated with gastrointestinal dysfunction. We have previously shown that transepithelial short circuit current, I_sc (chloride secretion), is significantly reduced in the jejunum from ob/ob mice vs lean controls, and consumption of 600 mg genistein/kg of diet (600 G) for 4 weeks significantly rescues I_sc. We aimed to evaluate whether morphological changes in the jejunal crypts contribute to the rescue of I_sc.

METHODS

Male mice (ob/ob and lean controls) were fed either a genistein-free diet or genistein-containing diet (600 G). Comparisons of crypt morphology were made for crypt depth, length, and numbers of proliferative cells. Assessments of crypt measures using DAPI and 5-ethynyl-2'-deoxyuridine (EdU) were performed using traditional cryostat sectioning and an innovative 3D optical clearing method.

RESULTS

We found that crypt length in the ob/ob genistein-fed group was significantly greater when measured with cleared tissue (85.19±4.73 µm, P<0.05, n=8) compared to lengths measured with cryostat (65.42±3.48 µm, n=8). In addition, proliferative EdU+ counts were approximately fivefold greater with clearing, compared to counts obtained via single plane images from cryostat sections for all groups measured. The average length to EdU+ ratio was unchanged between groups.

CONCLUSION

Thus, we conclude that genistein diet does not affect overall cellular proliferation or crypt morphology, other than for the modest increased crypt length measured via clearing in the ob/ob genistein group. The increase in crypt length is likely indicative of the greater accuracy of the 3D measures compared to single plane. Genistein diet-induced increases in the intestinal I_sc are therefore likely not attributed to changes in intestinal crypt morphology.

Optical clearing of small intestine for three-dimensional visualization of cellular proliferation within crypts

New methods on optical clearing provide a valuable alternative to traditional physical section histology. Optical clearing allows investigation of relatively large tissue samples at histological resolution while maintaining the three-dimensional architecture of the intact system. There is significant potential for applying optical clearing to gastrointestinal tissues. In particular, intestinal crypts contain high concentrations of stem cells, making these structures especially important for research on cellular proliferation in the intestinal epithelium. The objective of our study is to demonstrate an optical clearing method that is easy to implement and is compatible with mitotic fluorescent labeling. The optical clearing method we present utilizes a Triton/DMSO delipidization step followed by refractive index matching, rendering the tissue nearly transparent. We use EdU click chemistry to fluorescently label mitotic cell nuclei. Our results demonstrate successful clearing of jejunal samples with readily visible EdU staining by means of confocal microscopy. Three-dimensional reconstruction of labeled samples reveals preservation of intestinal cytoarchitecture including muscular, submucosal, and mucosal layers. Additionally, the morphology of intestinal crypts and individual EdU-positive mitotic nuclei are visible in sharp detail within their intact three-dimensional organization. In summary, we present an optical clearing method that is easy to implement and has the potential to provide more accurate assessment of cellular proliferation within the gastrointestinal tract in both healthy and disease states.

Dietary Genistein Influences Number of Acetylcholine Receptors in Female Diabetic Jejunum

BACKGROUND

Intestinal dysfunction in the ob/ob mouse model of diabetes mimics that seen clinically.

METHODS

We determined the effects of a 4-week genistein diet (600 mg genistein/kg food) on intestinal function (contractility, morphology, AChR, and motility) in female ob/ob and lean mice.

RESULTS

Contractility of the jejunum in response to incrementally increasing concentrations of KCl was comparable in ob/ob females and lean controls regardless of a genistein-diet. There were no changes in the wall thickness measured. We assessed the number of clusters of AChR in the jejunum wall; AChR were decreased by 48% in ob/ob mice versus leans, and the genistein diet reversed this. In utilizing a video-imaging system to evaluate gastrointestinal motility, we determined that the distance between consecutive contractile events was significantly increased by 1.87-fold in ob/ob mice versus leans, and the genistein diet was without effect.

CONCLUSIONS

These data suggest that slowed intestinal transit in the diabetic ob/ob mouse may be due in part to decreased AChR and decreased contraction events occurring per unit time. A genistein diet rescues the number of AChR to levels of leans yet did not change the number of contractile events. Feeding ob/ob mice a genistein-rich diet has potential therapeutic benefits towards improving the debilitating diabetes-related gastrointestinal dysfunction.

Regulation of intestinal SGLT1 by catestatin in hyperleptinemic type 2 diabetic mice

The small intestine is the major site for nutrient absorption that is critical in maintenance of euglycemia. Leptin, a key hormone involved in energy homeostasis, directly affects nutrient transport across the intestinal epithelium. Catestatin (CST), a 21-amino acid peptide derived from proprotein chromogranin A, has been shown to modulate leptin signaling. Therefore, we reasoned that leptin and CST could modulate intestinal Na(+)-glucose transporter 1 (SGLT1) expression in the context of obesity and diabetes. We found that hyperleptinemic db/db mice exhibit increased mucosal mass, associated with an enhanced proliferative response and decreased apoptosis in intestinal crypts, a finding absent in leptin-deficient ob/ob mice. Intestinal SGLT1 abundance was significantly decreased in hyperleptinemic but not leptin-deficient mice, indicating leptin regulation of SGLT1 expression. Phlorizin, a SGLT1/2 inhibitor, was without effect in an oral glucose tolerance test in db/db mice. The alterations in architecture and SGLT1 abundance were not accompanied by changes in the localization of intestinal alkaline phosphatase, indicating intact differentiation. Treatment of db/db mice with CST restored intestinal SGLT1 abundance and intestinal turnover, suggesting a cross-talk between leptin and CST, without affecting plasma leptin levels. Consistent with this hypothesis, we identified structural homology between CST and the AB-loop of leptin and protein-protein docking revealed binding of CST and leptin with the Ig-like binding site-III of the leptin receptor. In summary, downregulation of SGLT1 in an obese type 2 diabetic mouse model with hyperleptinemia is presumably mediated via the short form of the leptin receptor and reduces overt hyperglycemia.

Effect of keishibukuryogan on genetic and dietary obesity models

Obesity has been recognized as one of the most important risk factors for a variety of chronic diseases, such as diabetes, hypertension/cardiovascular diseases, steatosis/hepatitis, and cancer. Keishibukuryogan (KBG, Gui Zhi Fu Ling Wan in Chinese) is a traditional Chinese/Japanese (Kampo) medicine that has been known to improve blood circulation and is also known for its anti-inflammatory or scavenging effect. In this study, we evaluated the effect of KBG in two distinct rodent models of obesity driven by either a genetic (SHR/NDmcr-cp rat model) or dietary (high-fat diet-induced mouse obesity model) mechanism. Although there was no significant effect on the body composition in either the SHR rat or the DIO mouse models, KBG treatment significantly decreased the serum level of leptin and liver TG level in the DIO mouse, but not in the SHR rat model. Furthermore, a lower fat deposition in liver and a smaller size of adipocytes in white adipose tissue were observed in the DIO mice treated with KBG. Importantly, we further found downregulation of genes involved in lipid metabolism in the KBG-treated liver, along with decreased liver TG and cholesterol level. Our present data experimentally support in fact that KBG can be an attractive Kampo medicine to improve obese status through a regulation of systemic leptin level and/or lipid metabolism.