Transcriptome of the subcutaneous adipose tissue in response to oral supplementation of type 2 Leprdb obese diabetic mice with niacin-bound chromium

Adult skin fibroblast state change in murine wound healing

Wound healing is a well-organized dynamic process involving coordinated consecutive phases: homeostasis, inflammation, proliferation and resolution. Fibroblasts play major roles in skin wound healing such as in wound contraction and release of growth factors which are of importance in angiogenesis and tissue remodeling. Abnormal fibroblast phenotypes have been identified in patients with chronic wounds. In this work, we analyzed scRNA-seq datasets of normal and wounded skin from mice at day 4 post-wound to investigate fibroblast heterogeneity during the proliferative phase of wound healing. Compositional analysis revealed a specific subset of fibroblast (cluster 3) that primarily increased in wounded skin (14%) compared to normal skin (3.9%). This subset was characterized by a gene signature marked by the plasma membrane proteins Sfrp2 + Sfrp4 + Sfrp1 + and the transcription factors Ebf1 + Prrx1 + Maged1 + . Differential gene expression and enrichment analysis identified epithelial to mesenchymal transition (EMT) and angiogenesis to be upregulated in the emerging subset of fibroblasts of the wounded skin. Using two other datasets for murine wounded skin confirmed the increase in cluster 3-like fibroblasts at days 2, 7 and 14 post-wounding with a peak at day 7. By performing a similarity check between the differential gene expression profile between wounded and normal skin for this emerging fibroblast subset with drug signature from the ConnectivityMap database, we identified drugs capable of mimicking the observed gene expression change in fibroblasts during wound healing. TTNPB, verteprofin and nicotinic acid were identified as candidate drugs capable of inducing fibroblast gene expression profile necessary for wound healing. On the other hand, methocarbamol, ifosfamide and penbutolol were recognized to antagonize the identified fibroblast differential expression profile during wound healing which might cause delay in wound healing. Taken together, analysis of murine transcriptomic skin wound healing datasets suggested a subset of fibroblasts capable of inducing EMT and further inferred drugs that might be tested as potential candidates to induce wound closure.

Transcriptomics Curation of SARS-CoV-2 Related Host Genes in Mice With COVID-19 Comorbidity: A Pilot Study

The pandemic of coronavirus disease 2019 (COVID-19), a respiratory disease caused by a novel severe acute respiratory syndrome coronavirus-2, is causing substantial morbidity and mortality. Along with the respiratory symptoms, underlying diseases in senior patients, such as diabetes, hypertension, and coronary heart disease, are the most common comorbidities, which cause more severe outcomes and even death. During cellular attachment and entry of severe acute respiratory syndrome coronavirus-2, the key protein involved is the angiotensin I converting enzyme 2 (ACE2), which is located on the membrane of host cells. Here, we aim to curate an expression profile of Ace2 and other COVID-19 related genes across the available diabetes murine strains. Based on strictly manual curation and bioinformatics analysis of the publicly deposited expression datasets, Ace2 and other potentially involved genes such as Furin, Tmprss2, Ang, and Ang2 were examined. We found that Ace2 expression is rather ubiquitous in three selected diabetes prone strains (db/db, ob/ob and diet-induced obese). With the most abundant datasets present, the liver shows a medium Ace2 expression level compared with the lungs, pancreatic islets, brain and even T cells. Age is a more critical factor for Ace2 expression in db/db compared with the other two strains. Besides Ace2, the other four host genes showed varied levels of correlation to each other. To accelerate research on the interaction between COVID-19 and underlying diseases, the Murine4Covid transcriptomics database (www.geneureka.org/Murine4Covid) will facilitate the design of research on COVID-19 and comorbidities.

Is chromium pharmacologically relevant?

Recent research, combined with reanalysis of previous results, has revealed that chromium can no longer be considered an essential trace element. Clinical studies are ambiguous at best as to whether Cr has a pharmacological effect in humans. Observed effects of Cr on rodent models of insulin resistance and diabetes are best interpreted in terms of a pharmacological role for Cr. Studies on the effects of Cr on rat models of diabetes are reviewed herein and suggest Cr increases insulin sensitivity in peripheral tissues of the rodent models. The lack of effects in human studies may stem from humans receiving a comparably smaller dose than the rodent models. However, given the different responses to Cr in the rodent models, humans could potentially have different responses to Cr.

Chromium: is it essential, pharmacologically relevant, or toxic?

Over fifty years ago, the element chromium (as the trivalent ion) was proposed to be an essential element for mammals with a role in maintaining proper carbohydrate and lipid metabolism. Evidence for an essential role came from dietary studies with rodents, studies on the effects of chromium on subjects on total parenteral nutrition, and studies of the absorption and transport of chromium. Over the next several decades, chromium-containing nutritional supplements became so popular for weight loss and muscle development that sales were second only to calcium among mineral supplements. However, the failure to identify the responsible biomolecules(s) that bind chromium(III) and their mode of action, particularly a postulated species named glucose tolerance factor or GTF, resulted in the status of chromium being questioned in recent years, such that the question of its being essential needs to be formally readdressed. At the same time as chromium(III)'s popularity as a nutritional supplement was growing, concerns over its safety appeared. While chromium has been conclusively shown not to have beneficial effects on body mass or composition and should be removed from the list of essential trace elements, chromium(III) compounds are generally nontoxic and have beneficial pharmacological effects in rodents models of insulin insensitivity, although human studies have not conclusively shown any beneficial effects. Mechanisms have been proposed for these pharmacological effects, but all suffer from a lack of consistent supporting evidence.

Serum chromium levels in gestational diabetes mellitus

OBJECTIVE

To measure serum chromium level in women with gestational diabetes mellitus (GDM) from Chennai, South India.

MATERIALS AND METHODS

Thirty women with gestational diabetes, 60 age matched controls.

INCLUSION CRITERIA

Gestational age 22-28 weeks, age group 20-35 years.

EXCLUSION CRITERIA

Gestational age beyond 28 weeks, malnutrition or presence of infection. Serum chromium was measured using inductive couple plasma emission spectrometer.

RESULTS

Serum chromium levels of women with GDM, 1.59+/-0.02 ng/ml (range: 0.16-4.0 ng/ml) were lower than in controls (4.58+/-0.62 ng/ml; range 0.82-5.33 ng/ml) (P < 0.001). However, there were no significant differences among cases and controls when subdivided by parity.

CONCLUSIONS

Women with GDM from a South Indian city had lower levels of serum chromium compared to pregnant women without GDM. Studies may be done whether chromium supplementation is useful in this group of women.

Characterization of the organic component of low-molecular-weight chromium-binding substance and its binding of chromium

Chromium was proposed to be an essential element over 50 y ago and was shown to have therapeutic potential in treating the symptoms of type 2 diabetes; however, its mechanism of action at a molecular level is unknown. One chromium-binding biomolecule, low-molecular weight chromium-binding substance (LMWCr or chromodulin), has been found to be biologically active in in vitro assays and proposed as a potential candidate for the in vivo biologically active form of chromium. Characterization of the organic component of LMWCr has proven difficult. Treating bovine LMWCr with trifluoroacetic acid followed by purification on a graphite powder micro-column generates a heptapeptide fragment of LMWCr. The peptide sequence of the fragment was analyzed by MS and tandem MS (MS/MS and MS/MS/MS) using collision-induced dissociation and post-source decay. Two candidate sequences, pEEEEGDD and pEEEGEDD (where pE is pyroglutamate), were identified from the MS/MS experiments; additional tandem MS suggests the sequence is pEEEEGDD. The N-terminal glutamate residues explain the inability to sequence LMWCr by the Edman method. Langmuir isotherms and Hill plots were used to analyze the binding constants of chromic ions to synthetic peptides similar in composition to apoLMWCr. The sequence pEEEEGDD was found to bind 4 chromic ions per peptide with nearly identical cooperativity and binding constants to those of apoLMWCr. This work should lead to further studies elucidating or eliminating a potential role for LMWCr in treating the symptoms of type 2 diabetes and other conditions resulting from improper carbohydrate and lipid metabolism.

Oral administration of the high-chromium yeast improve blood plasma variables and pancreatic islet tissue in diabetic mice

The in vivo effects of oral administration of the high-chromium yeast to healthy and diabetic mice are described. Given that these complexes are proposed to function by potentiating the actions of insulin and activating the insulin receptor kinase, changes in lipid and carbohydrate metabolism would be expected. After 15 weeks administration (500 μg Cr/kg body mass) to healthy mice, abnormal metabolism and pathological change were not observed. After 15 weeks of treatment (0-1,000 μg Cr/kg body mass) of diabetic mice, the effect of high-chromium yeast on blood lipids and blood glycosylated hemoglobin (GHb) of diabetes are not consistent. High-chromium yeast results in a lowering (P < 0.05) of GHb and triglyceride, lowering (P < 0.01) of total cholesterol, and restoration (P < 0.01) of insulin; these results are in stark contrast to those of diabetic mice of administration of normal yeast, which have no effect on these parameters and serve as control group. The histopathological analysis of pancreas islet shows that high-chromium yeast could profoundly protect the impaired pancreatic islet and β-cells from inflammatory infiltration and fibrosis.

Improved function of diabetic wound-site macrophages and accelerated wound closure in response to oral supplementation of a fermented papaya preparation

Carica papaya Linn is widely known as a medicinal fruit. We sought to study a standardized fermented papaya preparation (FPP) for its effects on wound healing in adult obese diabetic (db/db) mice. FPP blunted the gain in blood glucose and improved the lipid profile after 8 weeks of oral supplementation. However, FPP did not influence weight gain during the supplementation period. FPP (0.2 g/kg body weight) supplementation for 8 weeks before wounding was effective in correcting wound closure. Studies on viable macrophages isolated from the wound site demonstrated that FPP supplementation improved respiratory-burst function as well as inducible NO production. Reactive oxygen species support numerous aspects of wound healing; NO availability in diabetic wounds is known to be compromised. Diabetic mice supplemented with FPP showed a higher abundance of CD68 as well as CD31 at the wound site, suggesting effective recruitment of monocytes and an improved proangiogenic response. This work provides the first evidence that diabetic-wound outcomes may benefit from FPP supplementation by specifically influencing the response of wound-site macrophages and the subsequent angiogenic response. Given that FPP has a long track record of safe human consumption, testing of the beneficial effects of FPP on diabetic wound-related outcomes in a clinical setting is warranted.

Chromium: celebrating 50 years as an essential element?

Fifty years ago the element chromium was proposed to be an essential element for mammals with a role in maintaining proper carbohydrate and lipid metabolism. Over the next several decades, chromium nutritional supplements became so popular for weight loss and muscle development that sales were second only to calcium among mineral supplements. However, the failure to identify the responsible biomolecules that bind Cr and their mode of action has resulted in the status of Cr being readdressed in recent years. This review considers research on the biochemistry of Cr(III) over the last two decades and how the results have affected the current status of Cr as an essential element.

Effects of dietary chromium (III) picolinate on growth performance, respiratory rate, plasma variables, and carcass traits of pigs fed high-fat diets

We investigated the effects of supplemental chromium (Cr) as Cr (III) picolinate on pigs fed high-fat diets (HFD) in a 56-day experiment. Thirty-two crossbred pigs (9.6 kg) were allotted to four treatments with four blocks and two pigs/pen. Treatments included: (1) low-fat diet (fat < 3.5%; LFD) with no Cr, (2) HFD (fat > 30%) with no Cr, (3) HFD with 1,000 ppb Cr, and (4) HFD with 2,000 ppb Cr. Pigs fed HFD gained weight faster, consumed less, and had lower feed:gain (p < 0.05). Pigs fed HFD had higher respiration rates than pigs fed LFD on d 41 (p < 0.05). Plasma insulin on d 14 linearly decreased with Cr (p = 0.05). Plasma cholesterol concentrations were higher in the pigs fed HFD than those fed LFD, but were largely unaffected by supplemental Cr. Consumption of HFD resulted in greater carcass weight, perirenal fat, and backfat measures (p < 0.01) compared with the LFD group. Cr resulted in linear reductions of hot carcass weight (p = 0.08) and average backfat (p < 0.05). The effects of Cr on carcass fat measures were more pronounced in castrated males than in females. These results indicate that Cr attenuates some effects of a HFD, mainly body fat accretion of pigs, and especially in castrated pigs.

Neuroprotective and antiinflammatory properties of a novel demethylated curcuminoid

A demethylated derivative of curcumin (DC; 67.8% bisdemethylcurcumin, 20.7% demethylmonodemethoxycurcumin, 5.86% bisdemethoxycurcumin, 2.58% demethylcurcumin) was prepared by using a 95% extract of curcumin (C(95); 72.2% curcumin, 18.8% monodemethoxycurcumin, 4.5% bisdemethoxycurcumin). DC increased glutathione and reduced reactive oxygen species (ROS) in HT4 neuronal cells. In a model of glutamate-induced death of HT4, DC was more effective than C(95) in neuroprotection. The protective effects of DC were retained even when DC was withdrawn from culture media after pretreatment. DC treatment, unlike an equal dose of C(95), completely spared glutamate-induced loss of cellular GSH. Both DC and C(95) prevented glutamate-induced elevation of cellular ROS but failed to attenuate glutamate-induced elevation of intracellular calcium. In human microvascular endothelial cells (HMECs) challenged with TNF-alpha, GeneChip analysis revealed that only a subcluster of 23 TNF-alpha-inducible genes were uniquely sensitive to C(95). In sharp contrast, 1,065 TNF-alpha-inducible genes were sensitive to DC but not to C(95), suggesting that DC was more effective in antagonizing the effects of TNF-alpha on HMECs. Functional analysis identified that the genes uniquely sensitive to DC belonged in four functional categories: cytokine-receptor interaction, focal adhesion, cell adhesion, and apoptosis. Real-time PCR as well as ELISA studies demonstrated that TNF-alpha-inducible CXCL10 and CXCL11 expression was sensitive to DC but not to C(95). Flow-cytometry studies recognized ICAM-1 and VCAM-1 as TNF-alpha-inducible adhesion molecules that were uniquely sensitive to DC. Taken together, DC exhibited promising neuroprotective and antiinflammatory properties that must be characterized in vivo.

Response of the adipose tissue transcriptome to dihydrotestosterone in mice

Androgens have been postulated to be important modulators of adipose tissue metabolism and fat cell function. In the present study, we investigated the response of male and female mice retroperitoneal adipose tissue to the nonaromatizable androgen dihydrotestosterone (DHT). Adipose tissue samples were obtained in gonadectomized animals treated with vehicle (control group), or injected with 0.1 mg DHT 1, 3, 6, 12, 18, and 24 h prior to necropsy. Fourteen animals were pooled at each time point (total 196 animals). Transcripts that were significantly modulated were considered as androgen-responsive genes. Quantitative real-time RT-PCR was used to confirm results from the microarray analysis in a subset of 46 probe sets in male mice and 98 probe sets in female mice. Considering peak time vs. control, we confirmed 74.0 and 63.3% of the modulated genes by PCR in males and females, respectively. Four genes were significantly stimulated in a similar manner by DHT in both sexes, namely metallothionein 1, growth arrest and DNA-damage-inducible 45 gamma, cyclin-dependent kinase inhibitor 1A, and fk506-binding protein 5. All these genes appear to be involved in the regulation of adipocyte differentiation/proliferation and adipogenesis. In conclusion, this study, which evaluated the acute transcriptome response of adipose tissue to DHT in male and female mice, suggests that DHT consistently modulates genes involved in the regulation of adipogenesis in retroperitoneal adipose tissue of both male and female animals.

Nutrigenomic analysis of diet-gene interactions on functional supplements for weight management

Recent advances in molecular biology combined with the wealth of information generated by the Human Genome Project have fostered the emergence of nutrigenomics, a new discipline in the field of nutritional research. Nutrigenomics may provide the strategies for the development of safe and effective dietary interventions against the obesity epidemic. According to the World Health Organization, more than 60% of the global disease burden will be attributed to chronic disorders associated with obesity by 2020. Meanwhile in the US, the prevalence of obesity has doubled in adults and tripled in children during the past three decades. In this regard, a number of natural dietary supplements and micronutrients have been studied for their potential in weight management. Among these supplements, (-)-hydroxycitric acid (HCA), a natural extract isolated from the dried fruit rind of Garcinia cambogia, and the micronutrient niacin-bound chromium(III) (NBC) have been shown to be safe and efficacious for weight loss. Utilizing cDNA microarrays, we demonstrated for the first time that HCA-supplementation altered the expression of genes involved in lipolytic and adipogenic pathways in adipocytes from obese women and up-regulated the expression of serotonin receptor gene in the abdominal fat of rats. Similarly, we showed that NBC-supplementation up-regulated the expression of myogenic genes while suppressed the expression of genes that are highly expressed in brown adipose tissue in diabetic obese mice. The potential biological mechanisms underlying the observed beneficial effects of these supplements as elucidated by the state-of-the-art nutrigenomic technologies will be systematically discussed in this review.

Characterization of the acute temporal changes in excisional murine cutaneous wound inflammation by screening of the wound-edge transcriptome

This work represents a maiden effort to systematically screen the transcriptome of the healing wound-edge tissue temporally using high-density GeneChips. Changes during the acute inflammatory phase of murine excisional wounds were characterized histologically. Sets of genes that significantly changed in expression during healing could be segregated into the following five sets: up-early (6-24 h; cytokine-cytokine receptor interaction pathway), up-intermediary (12-96 h; leukocyte-endothelial interaction pathway), up-late (48-96 h; cell-cycle pathway), down-early (6-12 h; purine metabolism) and down-intermediary (12-96 h; oxidative phosphorylation pathway). Results from microarray and real-time PCR analyses were consistent. Results listing all genes that were significantly changed at any specific time point were further mined for cell-type (neutrophils, macrophages, endothelial, fibroblasts, and pluripotent stem cells) specificity. Candidate genes were also clustered on the basis of their functional annotation, linking them to inflammation, angiogenesis, reactive oxygen species (ROS), or extracellular matrix (ECM) categories. Rapid induction of genes encoding NADPH oxidase subunits and downregulation of catalase in response to wounding is consistent with the fact that low levels of endogenous H2O2 is required for wound healing. Angiogenic genes, previously not connected to cutaneous wound healing, that were induced in the healing wound-edge included adiponectin, epiregulin, angiomotin, Nogo, and VEGF-B. This study provides a digested database that may serve as a valuable reference tool to develop novel hypotheses aiming to elucidate the biology of cutaneous wound healing comprehensively.

Transcriptome of primary adipocytes from obese women in response to a novel hydroxycitric acid-based dietary supplement

BACKGROUND

Obesity is a global public health problem. Traditional herbal medicines may have some potential in managing obesity. The dried fruit rind of Garcinia cambogia, also known as Malabar tamarind, is a unique source of (-)-hydroxycitric acid (HCA), which exhibits a distinct sour taste and has been safely used for centuries in Southeastern Asia to make meals more filling. Recently it has been demonstrated that when taken orally, a novel, highly soluble calcium/potassium salt of HCA (HCA-SX) is safe and bioavailable in the human plasma. Although HCA-SX seems to be conditionally effective in weight management in experimental animals and in humans, its mechanism of action remains unclear.

METHODS

In this study, subcutaneous preadipocytes collected from obese women with body mass index>25 kg/m2 were differentiated to adipocytes for 2 weeks in culture. The effects of low-dose HCA-SX on lipid metabolism and on the adipocyte transcriptome were tested. HCA-SX augmented isoproterenol- and 3-isobutyryl-1-methylxanthine-induced lipolysis. Using oil red O, the production of lipid storage droplets by the cultured mature human adipocytes was visualized and enumerated.

RESULTS

HCA-SX caused droplet dispersion facilitating lipase action on the lipids. HCA-SX markedly induced leptin expression in the adipocytes. In the microarray analyses, a total of 54,676 probe sets were screened. HCA-SX resulted in significant down-regulation of 348, and induction of 366 fat- and obesity-related genes. HCA-SX induced transactivation of hypoxia inducible factor (HIF), a novel approach in the management of obesity.

CONCLUSION

Taken together, the net effects support the antilipolytic and antiadipogenic effects of HCA-SX. Further human studies are warranted.

Effect of chromium niacinate and chromium picolinate supplementation on lipid peroxidation, TNF-alpha, IL-6, CRP, glycated hemoglobin, triglycerides, and cholesterol levels in blood of streptozotocin-treated diabetic rats

Chromium (Cr(3+)) supplementation facilitates normal protein, fat, and carbohydrate metabolism, and is widely used by the public in many countries. This study examined the effect of chromium niacinate (Cr-N) or chromium picolinate (Cr-P) supplementation on lipid peroxidation (LP), TNF-alpha, IL-6, C-reactive protein (CRP), glycosylated hemoglobin (HbA(1)), cholesterol, and triglycerides (TG) in diabetic rats. Diabetes (D) was induced in Sprague-Dawley rats by streptozotocin (STZ) (ip, 65 mg/kg BW). Control buffer, Cr-N, or Cr-P (400 microg Cr/kg BW) was administered by gavages daily for 7 weeks. Blood was collected by heart puncture using light anesthesia. Diabetes caused a significant increase in blood levels of TNF-alpha, IL-6, glucose, HbA(1), cholesterol, TG, and LP. Compared with D, Cr-N supplementation lowered the blood levels of TNF-alpha (P=0.04), IL-6 (P=0.02), CRP (P=0.02), LP (P=0.01), HbA(1) (P=0.02), TG (P=0.04), and cholesterol (P=0.04). Compared with D, Cr-P supplementation showed a decrease in TNF-alpha (P=0.02), IL-6 (P=0.02), and LP (P=0.01). Chromium niacinate lowers blood levels of proinflammatory cytokines (TNF-alpha, IL-6, CRP), oxidative stress, and lipids levels in diabetic rats, and appears to be a more effective form of Cr(3+) supplementation. This study suggests that Cr(3+) supplementation can lower the risk of vascular inflammation in diabetes.

High glucose and ketosis (acetoacetate) increases, and chromium niacinate decreases, IL-6, IL-8, and MCP-1 secretion and oxidative stress in U937 monocytes

Elevated blood levels of the proinflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8), and MCP-1 (monocyte chemoattractant protein-1) increase insulin resistance and the risk of cardiovascular disease (CVD). There is no previous study that has examined the effect of ketosis and trivalent chromium on IL-6, IL-8, or MCP-1 secretion in any cell type or in human or animal model. The authors examined the hypothesis that ketosis increases and trivalent chromium decreases the levels of cytokines and oxidative stress in diabetes using a U937 monocyte cell culture model. Cells were cultured with control, high glucose (HG), and acetoacetate (AA) in the absence or presence (0.5-10 microM) of CrCl(3), chromium picolinate (Cr-P), or chromium niacinate (Cr-N) at 37 degrees C for 24 h. The data show a significant stimulation of IL-6, IL-8, and MCP-1 secretion and an increase in oxidative stress in cells treated with HG or AA. The effect of HG on cytokine secretion was reduced by Cr-N, and to a lesser extent by CrCl(3) and Cr-P. The effect of HG on oxidative stress was reduced by Cr-N and CrCl 3, but not by Cr-P. Similarly, Cr-N decreased the cytokine secretion in HG + AA-treated cells. Cr-N significantly decreased standard oxidant (H(2)O(2)) induced cytokine secretion, which suggests that reduction of cytokine secretion by Cr-N is in part mediated by its antioxidative effect. In a cell culture model, Cr-N appears to be the most effective form of chromium in inhibiting oxidative stress and proinflammatory cytokine secretion by monocytes. This study suggests that chromium niacinate supplementation may be useful in reducing vascular inflammation and the risk of CVD in diabetes.