Polypharmakologische Strategien zur Behandlung von Adipositas und zur Verbesserung mehrerer Aspekte des metabolischen Syndroms bei Mäusen

Obesity and its comorbidities, such as type 2 diabetes mellitus (T2DM), are major threats to worldwide health. In this PhD thesis, I tested the efficacy of two novel polypharmacological approaches to induce body weight loss and ameliorate associated metabolic complications in diet-induced obese mice. In the first approach, we aimed to in vivo pharmacologically mimic the hormonal changes that occur upon bariatric surgery. In the second approach, we aimed to in vivo mimic the two canonical modulators of human energy metabolism – tobacco smoking and cold exposure. Most importantly, with the presented PhD thesis, I contributed to the preclinical evaluation of urgently needed novel pharmacological options to treat obesity and associated diseases.Adipositas und Begleiterkrankungen wie Typ-2-Diabetes mellitus stellen eine gesundheitliche Bedrohung für die Bevölkerung dar. In dieser Doktorarbeit habe ich die Wirksamkeit zweier neuer polypharmakologischer Ansätze getestet in Diät-induzierten fettleibigen Mäusen das Körpergewicht zu reduzieren und assoziierte metabolische Komplikationen zu verbessern. In unabhängigen Studien habe ich sowohl die hormonellen Veränderungen, die nach bariatrischen Operationen auftreten, als auch die beiden kanonischen Modulatoren des menschlichen Energiestoffwechsels - Tabakrauchen und Kälteexposition - pharmakologisch nachgeahmt. Zusammenfassend habe ich mit der Doktorarbeit zur präklinischen Evaluation dringend benötigter neuer pharmakologischer Optionen zur Behandlung von Fettleibigkeit und damit verbundenen metabolischen Erkrankungen beigetragen

Polypharmakologische Strategien zur Behandlung von Adipositas und zur Verbesserung mehrerer Aspekte des metabolischen Syndroms bei Mäusen

Obesity and its comorbidities, such as type 2 diabetes mellitus (T2DM), are major threats to worldwide health. In this PhD thesis, I tested the efficacy of two novel polypharmacological approaches to induce body weight loss and ameliorate associated metabolic complications in diet-induced obese mice. In the first approach, we aimed to in vivo pharmacologically mimic the hormonal changes that occur upon bariatric surgery. In the second approach, we aimed to in vivo mimic the two canonical modulators of human energy metabolism – tobacco smoking and cold exposure. Most importantly, with the presented PhD thesis, I contributed to the preclinical evaluation of urgently needed novel pharmacological options to treat obesity and associated diseases.Adipositas und Begleiterkrankungen wie Typ-2-Diabetes mellitus stellen eine gesundheitliche Bedrohung für die Bevölkerung dar. In dieser Doktorarbeit habe ich die Wirksamkeit zweier neuer polypharmakologischer Ansätze getestet in Diät-induzierten fettleibigen Mäusen das Körpergewicht zu reduzieren und assoziierte metabolische Komplikationen zu verbessern. In unabhängigen Studien habe ich sowohl die hormonellen Veränderungen, die nach bariatrischen Operationen auftreten, als auch die beiden kanonischen Modulatoren des menschlichen Energiestoffwechsels - Tabakrauchen und Kälteexposition - pharmakologisch nachgeahmt. Zusammenfassend habe ich mit der Doktorarbeit zur präklinischen Evaluation dringend benötigter neuer pharmakologischer Optionen zur Behandlung von Fettleibigkeit und damit verbundenen metabolischen Erkrankungen beigetragen

Polypharmakologische Strategien zur Behandlung von Adipositas und zur Verbesserung mehrerer Aspekte des metabolischen Syndroms bei Mäusen

Obesity and its comorbidities, such as type 2 diabetes mellitus (T2DM), are major threats to worldwide health. In this PhD thesis, I tested the efficacy of two novel polypharmacological approaches to induce body weight loss and ameliorate associated metabolic complications in diet-induced obese mice. In the first approach, we aimed to in vivo pharmacologically mimic the hormonal changes that occur upon bariatric surgery. In the second approach, we aimed to in vivo mimic the two canonical modulators of human energy metabolism – tobacco smoking and cold exposure. Most importantly, with the presented PhD thesis, I contributed to the preclinical evaluation of urgently needed novel pharmacological options to treat obesity and associated diseases.Adipositas und Begleiterkrankungen wie Typ-2-Diabetes mellitus stellen eine gesundheitliche Bedrohung für die Bevölkerung dar. In dieser Doktorarbeit habe ich die Wirksamkeit zweier neuer polypharmakologischer Ansätze getestet in Diät-induzierten fettleibigen Mäusen das Körpergewicht zu reduzieren und assoziierte metabolische Komplikationen zu verbessern. In unabhängigen Studien habe ich sowohl die hormonellen Veränderungen, die nach bariatrischen Operationen auftreten, als auch die beiden kanonischen Modulatoren des menschlichen Energiestoffwechsels - Tabakrauchen und Kälteexposition - pharmakologisch nachgeahmt. Zusammenfassend habe ich mit der Doktorarbeit zur präklinischen Evaluation dringend benötigter neuer pharmakologischer Optionen zur Behandlung von Fettleibigkeit und damit verbundenen metabolischen Erkrankungen beigetragen

Pirt deficiency has subtle female-specific effects on energy and glucose metabolism in mice

Objective: The contribution of brown adipose tissue (BAT) to adult human metabolic control is a topic of ongoing investigation. In context, understanding the cellular events leading to BAT uncoupling, heat production, and energy expenditure is anticipated to produce significant insight into this endeavor. The phosphoinositide interacting regulator of transient receptor potentials (Pirt) was recently put forward as a key protein regulating cold sensing downstream of the transient receptor potential melastatin 8 (TRPM8). Notably, TRPM8 has been identified as a non-canonical regulator of BAT thermogenesis. The aim of this investigation was to delineate the role of Pirt in energy homeostasis and glucose metabolism - and the possible involvement of Pirt in TRPM8-elicited energy expenditure. Methods: To this end, we metabolically phenotyped male and female Pirt deficient (Pirt−/−) mice exposed to a low-fat chow diet or to a high-fat, high-sugar (HFHS) diet. Results: We identified that chow-fed female Pirt−/− mice have an increased susceptibility to develop obesity and glucose intolerance. This effect is abrogated when the mice are exposed to a HFHS diet. Conversely, Pirt−/− male mice display no metabolic phenotype on either diet relative to wild-type (WT) control mice. Finally, we observed that Pirt is dispensable for TRPM8-evoked energy expenditure. Conclusion: We here report subtle metabolic abnormalities in female, but not male, Pirt−/− mice. Future studies are required to tease out if metabolic stressors beyond dietary interventions, e.g. temperature fluctuations, are interacting with Pirt-signaling and metabolic control in a sex-specific fashion. Keywords: Signaling molecule, Sex differences, Body weight, Energy metabolism, TRPM8, Brown adipose tissu

Monomeric GLP-1/GIP/glucagon triagonism corrects obesity, hepatosteatosis, and dyslipidemia in female mice

Objective: Obesity is a major health threat that affects men and women equally. Despite this fact, weight-loss potential of pharmacotherapies is typically first evaluated in male mouse models of diet-induced obesity (DIO). To address this disparity we herein determined whether a monomeric peptide with agonism at the receptors for glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon is equally efficient in correcting DIO, dyslipidemia, and glucose metabolism in DIO female mice as it has been previously established for DIO male mice. Methods: Female C57BL/6J mice and a cohort of fatmass-matched C57BL/6J male mice were treated for 27 days via subcutaneous injections with either the GLP-1/GIP/glucagon triagonist or PBS. A second cohort of C57BL/6J male mice was included to match the females in the duration of the high-fat, high-sugar diet (HFD) exposure. Results: Our results show that GLP-1/GIP/glucagon triple agonism inhibits food intake and decreases body weight and body fat mass with comparable potency in male and female mice that have been matched for body fat mass. Treatment improved dyslipidemia in both sexes and reversed diet-induced steatohepatitis to a larger extent in female mice compared to male mice. Conclusions: We herein show that a recently developed unimolecular peptide triagonist is equally efficient in both sexes, suggesting that this polypharmaceutical strategy might be a relevant alternative to bariatric surgery for the treatment of obesity and related metabolic disorders. Keywords: Obesity, Sex differences, Diabetes, Glucose homeostasis, Dyslipidemia, Pharmacotherap

Pharmacological targeting of α3β4 nicotinic receptors improves peripheral insulin sensitivity in mice with diet-induced obesity

Aims/hypothesis Treatment with the alpha 3 beta 4 nicotinic acetylcholine receptor (nAChR) agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), improves glucose tolerance in diet-induced obese (DIO) mice, but the physiological and molecular mechanisms are unknown. Methods DMPP (10 mg/kg body weight, s.c.) was administered either in a single injection (acute) or daily for up to 14 days (chronic) in DIO wild-type (WT) and Chrnb4 knockout (KO) mice and glucose tolerance, tissue-specific tracer-based glucose metabolism, and insulin signalling were assessed. Results In WT mice, but not in Chrnb4 KO mice, single acute treatment with DMPP induced transient hyperglycaemia, which was accompanied by high plasma adrenaline (epinephrine) levels, upregulated hepatic gluconeogenic genes, and decreased hepatic glycogen content. In contrast to these acute effects, chronic DMPP treatment in WT mice elicited improvements in glucose tolerance already evident after three consecutive days of DMPP treatment. After seven days of DMPP treatment, glucose tolerance was markedly improved, also in comparison with mice that were pair-fed to DMPP-treated mice. The glycaemic benefit of chronic DMPP was absent in Chrnb4 KO mice. Chronic DMPP increased insulin-stimulated glucose clearance into brown adipose tissue (+69%), heart (+93%), gastrocnemius muscle (+74%) and quadriceps muscle (+59%), with no effect in white adipose tissues. After chronic DMPP treatment, plasma adrenaline levels did not increase following an injection with DMPP. In glucose-stimulated skeletal muscle, we detected a decreased phosphorylation of the inhibitory Ser640 phosphorylation site on glycogen synthase and a congruent increase in glycogen accumulation following chronic DMPP treatment. Conclusions/interpretation Our data suggest that DMPP acutely induces adrenaline release and hepatic glycogenolysis, while chronic DMPP-mediated activation of beta 4-containing nAChRs improves peripheral insulin sensitivity independently of changes in body weight via mechanisms that could involve increased non-oxidative glucose disposal into skeletal muscle

Pharmacological targeting of α3β4 nicotinic receptors improves peripheral insulin sensitivity in mice with diet-induced obesity

ims/hypothesisTreatment with theα3β4 nicotinic acetylcholine receptor (nAChR) agonist, 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), improves glucose tolerance in diet-induced obese (DIO) mice, but the physiological andmolecular mechanisms are unknown.MethodsDMPP (10 mg/kg body weight, s.c.) was administered either in a single injection (acute) or daily for up to 14 days(chronic) in DIO wild-type (WT) andChrnb4knockout (KO) mice and glucose tolerance, tissue-specific tracer-based glucosemetabolism, and insulin signalling were assessed.ResultsIn WT mice, but not inChrnb4KO mice, single acute treatment with DMPP induced transient hyperglycaemia,which was accompanied by high plasma adrenaline (epinephrine) levels, upregulated hepatic gluconeogenic genes, anddecreased hepatic glycogen content. In contrast to theseacute effects, chronic DMPP treatment in WT mice elicitedimprovements in glucose tolerance already evident after three consecutive days of DMPP treatment. After seven days ofDMPP treatment, glucose tolerance was markedly improved,alsoincomparisonwithmicethatwerepair-fedtoDMPP-treated mice. The glycaemic benefit of chronic DMPP was absent inChrnb4KO mice. Chronic DMPP increased insulin-stimulated glucose clearance into brown adipose tissue(+69%), heart (+93%), gastrocnemius muscle (+74%) andquadriceps muscle (+59%), with no effect in white adipose tissues. After chronic DMPP treatment, plasma adrenalinelevels did not increase following an injection with DMPP. In glucose-stimulated skeletal muscle, we detected a decreasedphosphorylation of the inhibitory Ser640 phosphorylation site on glycogen synthase and a congruent increase in glyco-gen accumulation following chronic DMPP treatment.Conclusions/interpretationOur data suggest that DMPP acutely induces adrenaline release and hepatic glycogenolysis,while chronic DMPP-mediated activation ofβ4-containing nAChRs improves peripheral insulin sensitivity independent-ly of changes in body weight via mechanisms that could involve increased non-oxidative glucose disposal into skeletalmuscle.publishe

A high-content endogenous GLUT4 trafficking assay reveals new aspects of adipocyte biology.

Funder: Wellcome-MRC, Institute of Metabolic Science, Metabolic Research Laboratories, Imaging CoreInsulin-induced GLUT4 translocation to the plasma membrane in muscle and adipocytes is crucial for whole-body glucose homeostasis. Currently, GLUT4 trafficking assays rely on overexpression of tagged GLUT4. Here we describe a high-content imaging platform for studying endogenous GLUT4 translocation in intact adipocytes. This method enables high fidelity analysis of GLUT4 responses to specific perturbations, multiplexing of other trafficking proteins and other features including lipid droplet morphology. Using this multiplexed approach we showed that Vps45 and Rab14 are selective regulators of GLUT4, but Trarg1, Stx6, Stx16, Tbc1d4 and Rab10 knockdown affected both GLUT4 and TfR translocation. Thus, GLUT4 and TfR translocation machinery likely have some overlap upon insulin-stimulation. In addition, we identified Kif13A, a Rab10 binding molecular motor, as a novel regulator of GLUT4 traffic. Finally, comparison of endogenous to overexpressed GLUT4 highlights that the endogenous GLUT4 methodology has an enhanced sensitivity to genetic perturbations and emphasises the advantage of studying endogenous protein trafficking for drug discovery and genetic analysis of insulin action in relevant cell types