The enduring metabolic improvement of combining dual amylin and calcitonin receptor agonist and semaglutide treatments in a rat model of obesity and diabetes.

Long-acting dual amylin and calcitonin receptor agonists (DACRAs) are novel candidates for the treatment of type 2 diabetes and obesity due to their beneficial effects on body weight, glucose control, and insulin action. However, how the metabolic benefits are maintained after long-lasting treatment is unknown. This study investigates the long-term anti-obesity and anti-diabetic treatment efficacy of the DACRA KBP-336 alone and combined with the GLP-1 analog semaglutide. Zucker diabetic Sprague Dawley (ZDSD) rats with obesity and diabetes received KBP-336 (4.5 nmol/kg Q3D), semaglutide (50 nmol/kg Q3D), or the combination for 7 mo, and the treatment impact on body weight, food intake, glucose control, and insulin action was evaluated. Furthermore, serum levels of the cardiac fibrosis biomarker endotrophin were evaluated. KBP-336, semaglutide, and the combination lowered body weight significantly compared with the vehicle, with the combination inducing a larger and more sustained weight loss than either monotherapy. All treatments resulted in reduced fasting blood glucose levels and HbA1c levels and improved glucose tolerance compared with vehicle-treated rats. Furthermore, all treatments protected against lost insulin secretory capacity and improved insulin action. Serum levels of endotrophin were significantly lowered by KBP-336 compared with vehicle. This study shows the benefit of combining KBP-336 and semaglutide to obtain significant and sustained weight loss, as well as improved glucose control. Furthermore, KBP-336-driven reductions in circulating endotrophin indicate a clear reduction in the risk of complications. Altogether, KBP-336 is a promising candidate for the treatment of obesity and type 2 diabetes both alone and in combination with GLP-1 analogs.NEW & NOTEWORTHY These studies describe the benefit of combining dual amylin and calcitonin receptor agonists (DACRA) with semaglutide for long-term treatment of obesity and type 2 diabetes. Combination treatment induced sustained weight loss and improved glucose control. A DACRA-driven reduction in a serological biomarker of cardiac fibrosis indicated a reduced risk of complications. These results highlight DACRAs as a promising candidate for combination treatment of obesity and type 2 diabetes and related long-term complications.

Are insulin sensitizers the new strategy to treat Type 1 diabetes? A long-acting dual amylin and calcitonin receptor agonist improves insulin-mediated glycaemic control and controls body weight.

BACKGROUND AND PURPOSE: Insulin therapies for Type 1 diabetes (T1D) have limitations, such as glucose fluctuations, hypoglycaemia, and weight gain. Only pramlintide is approved with insulin. However, its short half-life limits efficacy, requiring multiple daily injections and increasing hypoglycaemia risk. New strategies are needed to improve glycaemic control. Dual amylin and calcitonin receptor agonists are potent insulin sensitizers developed for Type 2 diabetes (T2D) as they improve glucose control, reduce body weight, and attenuate hyperglucagonemia. However, it is uncertain if they could be used to treat T1D. EXPERIMENTAL APPROACH: Sprague Dawley rats received a single intravenous injection of streptozotocin (STZ) (50 mg·kg-1) to induce T1D. Humulin (1 U/200 g·day-1 or 2 U/200 g·day-1) was continuously infused, while half of the rats received additional KBP-336 (4.5 nmol·kg-1 Q3D) treatment. Bodyweight, food intake, and blood glucose were monitored throughout the study. An oral glucose tolerance test was performed during the study. KEY RESULTS: Treatment with Humulin or Humulin + KBP-336 improved the health of STZ rats. Humulin increased body weight in STZ rats, but KBP-336 attenuated these increases and maintained a significant weight loss. The combination exhibited greater blood glucose reductions than Humulin-treated rats alone, reflected by improved HbA1c levels and glucose control. The combination prevented hyperglucagonemia, reduced amylin levels, and increased pancreatic insulin content, indicating improved insulin sensitivity and beta-cell preservation. CONCLUSION AND IMPLICATIONS: The insulin sensitizer KBP-336 lowered glucagon secretion while attenuating insulin-induced weight gain. Additionally, KBP-336 may prevent hypoglycaemia and improve insulin resistance, which could be a significant advantage for individuals with T1D seeking therapeutic benefits.

Dual amylin and calcitonin receptor agonist treatment reduces biomarkers associated with kidney fibrosis in diabetic rats.

Dual amylin and calcitonin receptor agonists (DACRAs) are effective treatments for obesity and type 2 diabetes (T2D). They provide beneficial effects on body weight, glucose control, and insulin action. However, whether DACRAs protect against diabetes-related kidney damage remains unknown. We characterize the potential of long-acting DACRAs (KBP-A, Key Bioscience Peptide-A) as a treatment for T2D-related pathological alterations of the kidney extracellular matrix (ECM) in Zucker diabetic fatty rats (ZDF). We examined levels of endotrophin (profibrotic signaling molecule reflecting collagen type VI formation) and tumstatin (matrikine derived from collagen type IVα3) in serum and evaluated kidney morphology and collagen deposition in the kidneys. We included a study in obese Sprague-Dawley rats to further investigate the impact of KBP-A on ECM biomarkers. In ZDF vehicles, levels of endotrophin and tumstatin increased, suggesting disease progression along with an increase in blood glucose levels. These rats also displayed damage to their kidneys, which was evident from the presence of collagen formation in the medullary region of the kidney. Interestingly, KBP-A treatment attenuated these increases, resulting in significantly lower levels of endotrophin and tumstatin than the vehicle. Levels of endotrophin and tumstatin were unchanged in obese Sprague-Dawley rats, supporting the relation to diabetes-related kidney complications. Furthermore, KBP-A treatment normalized collagen deposition in the kidney while improving glucose control. These studies confirm the beneficial effects of DACRAs on biomarkers associated with kidney fibrosis. Moreover, these antifibrotic effects are likely associated with improved glucose control, highlighting KBP-A as a promising treatment of T2D and its related late complications.NEW & NOTEWORTHY These studies describe the beneficial effects of using a dual amylin and calcitonin receptor agonist (DACRA) for diabetes-related kidney complications. DACRA treatment reduced levels of serological biomarkers associated with kidney fibrosis. These reductions were further reflected by reduced collagen expression in diabetic kidneys. In general, these results validate the use of serological biomarkers while demonstrating the potential effect of DACRAs in treating diabetes-related long-term complications.

Treatment sequencing using the dual amylin and calcitonin receptor agonist KBP-336 and semaglutide results in durable weight loss.

OBJECTIVE: Long-acting dual amylin and calcitonin receptor agonists (DACRAs) hold great promise as potential treatments for obesity and its associated comorbidities. These agents have demonstrated beneficial effects on body weight, glucose control, and insulin action mirroring the effects observed with glucagon-like peptide-1 (GLP-1) agonist treatment. Strategies aimed at enhancing and prolonging treatment efficacy include treatment sequencing and combination therapy. Here, we sought to investigate the impact of switching between or combining treatment with the DACRA KBP-336 and the GLP-1 analog semaglutide in fed rats with obesity induced by a high-fat diet (HFD). METHODS: Two studies were performed in which HFD-induced obese Sprague Dawley rats were switched between treatment with KBP-336 (4.5 nmol/kg, Q3D) and semaglutide (50 nmol/kg, Q3D) or a combination of the two. Treatment efficacy on weight loss and food intake was evaluated, and glucose tolerance was assessed by oral glucose tolerance tests. RESULTS: KBP-336 and semaglutide monotherapy resulted in a similar reduction in body weight and food intake. Treatment sequencing resulted in continuous weight loss and all monotherapies resulted in similar weight loss independent of the treatment regimen (P < 0.001 compared to vehicle). The combination of KBP-336 and semaglutide significantly improved the weight loss compared to either monotherapy alone (P < 0.001), which was evident in the adiposity at the study end. All treatments improved glucose tolerance, with the KBP-effect on insulin sensitivity as the dominant response. CONCLUSIONS: These findings highlight KBP-336 as a promising anti-obesity therapy both alone, in treatment sequencing, and in combination with semaglutide or other incretin-based therapies.

Dual amylin and calcitonin receptor agonist treatment improves insulin sensitivity and increases muscle-specific glucose uptake independent of weight loss.

Dual amylin and calcitonin receptor agonists (DACRAs) are known to induce significant weight loss as well as improve glucose tolerance, glucose control, and insulin action in rats. However, to what extent DACRAs affect insulin sensitivity beyond that induced by weight loss and if DACRAs affect glucose turnover including tissue-specific glucose uptake is still unknown. Hyperinsulinemic glucose clamp studies were carried out in pre-diabetic ZDSD and diabetic ZDF rats treated with either the DACRA KBP or the long-acting DACRA KBP-A for 12 days. The glucose rate of disappearance was assessed using 3-3H glucose and tissue-specific glucose uptake was evaluated using 14C-2-deoxy-D-glucose (14C-2DG). In diabetic ZDF rats, KBP treatment significantly reduced fasting blood glucose and improved insulin sensitivity independent of weight loss. Furthermore, KBP increased the rate of glucose clearance, likely by increasing glucose storage, but without altering the endogenous glucose production. This was confirmed in pre-diabetic ZDSD rats. Direct assessment of tissue-specific glucose uptake showed, that both KBP and KBP-A significantly increased glucose uptake in muscles. In summary, KBP treatment significantly improved insulin sensitivity in diabetic rats and markedly increased glucose uptake in muscles. Importantly, in addition to their well-established weight loss potential, the KBPs have an insulin-sensitizing effect independent of weight loss, highlighting DACRAs as promising agents for the treatment of type 2 diabetes and obesity.

Improved metabolic efficacy of a dual amylin and calcitonin receptor agonist when combined with semaglutide or empagliflozin.

Pharmacotherapies for obesity and type 2 diabetes (T2D) are thought to bridge the gap between lifestyle modification and the weight loss obtained with bariatric surgery. Although the effect of monotherapies, namely amylin and glucagon-like peptide-1 receptor (GLP-1R) agonists, has shown great potential, combination therapy is now becoming a strategy to optimize efficacy for weight management while minimizing adverse effects. This study investigated a dual amylin and calcitonin receptor agonist (DACRA); KBP-066A in combination with the GLP-1R agonist semaglutide or the sodium-glucose co transporter-2 inhibitor (SGLT2i) empagliflozin for anti-obesity and anti-diabetic treatment. The effect of KBP-066A, semaglutide, and empagliflozin alone and in combination was studied with respect to their impact on body weight, food intake, and glucose metabolism in high-fat diet (HFD) and Zucker diabetic fatty (fa/fa) (ZDF) rats. Treatment with KBP-066A and semaglutide lowered body weight by 13% and 9.7%. In contrast, a combination of both KBP-066A + semaglutide reduced body weight by 21% in HFD rats demonstrating superiority compared to monotherapies alone. A combination of KBP-066A with semaglutide or empagliflozin significantly lowered fasting blood glucose, and HbA1C (%) levels in ZDF rats. The complementary action by KBP-066A to GLP-1R agonist and SGLT2i on BW, food intake and glucose control endorsed the potential of DACRAs as an add-on therapy to therapeutic options for T2D and obesity.

The Effects of Dual GLP-1/Glucagon Receptor Agonists with Different Receptor Selectivity in Mouse Models of Obesity and Nonalcoholic Steatohepatitis.

There is an unmet need for nonalcoholic steatohepatitis (NASH) therapeutics, considering the increase in global obesity. Dual GLP-1/glucagon (GCG) receptor agonists have shown beneficial effects in circumventing the pathophysiology linked to NASH. However, dual GLP-1/GCG receptor agonists as a treatment of metabolic diseases need delicate optimization to maximize metabolism effects. The impacts of increased relative GLP-1/GCG receptor activity in NASH settings must be addressed to unleash the full potential. In this study, we investigated the potential of OXM-104 and OXM-101, two dual GLP-1/GCG receptor agonists with different receptor selectivity in the setting of NASH, to establish the relative receptor activities leading to the best metabolic outcome efficacies to reduce the gap between surgery and pharmacological interventions. We developed dual GLP-1/GCG receptor agonists with selective agonism. Despite the improved metabolic effects of OXM-101, we explored a hyperglycemic risk attached to increased relative GCG receptor agonism. Thirty-eight days of treatment with a dual GLP-1/GCG receptor agonist, OXM-104, with increased GLP-1 receptor agonism in obese NASH mice was found to ameliorate the development of NASH by lowering body weight, improving liver and lipid profiles, reducing the levels of the fibrosis marker PRO-C4, and improving glucose control. Similarly, dual GLP-1/GCG receptor agonist OXM-101 with increased relative GCG receptor agonism ameliorated NASH by eliciting dramatic body weight reductions to OXM-104, reflected in the improvement of liver and lipid enzymes and reduced PRO-C4 levels. Optimizing dual GLP-1/GCG agonists with increased relative GCG receptor agonism can provide the setting for future agonists to treat obesity, type 2 diabetes, and NASH without having a hyperglycemic risk. SIGNIFICANT STATEMENT: There is an unmet need for nonalcoholic steatohepatitis (NASH) therapeutics, considering the increase in global obesity. Dual GLP-1/glucagon (GCG) receptor agonists have shown beneficial effects in circumventing the pathophysiology linked to NASH. Therefore, this study has examined OXM-104 and OXM-101, two dual GLP-1/GCG receptor agonists in the setting of NASH, to establish the relative receptor activities leading to the best metabolic outcome efficacies to reduce the gap between surgery and pharmacological interventions.

Gene therapy for infantile malignant osteopetrosis: review of pre-clinical research and proof-of-concept for phenotypic reversal.

Infantile malignant osteopetrosis is a devastating disorder of early childhood that is frequently fatal and for which there are only limited therapeutic options. Gene therapy utilizing autologous hematopoietic stem and progenitor cells represents a potentially advantageous therapeutic alternative for this multisystemic disease. Gene therapy can be performed relatively rapidly following diagnosis, will not result in graft versus host disease, and may also have potential for reduced incidences of other transplant-related complications. In this review, we have summarized the past sixteen years of research aimed at developing a gene therapy for infantile malignant osteopetrosis; these efforts have culminated in the first clinical trial employing lentiviral-mediated delivery of TCIRG1 in autologous hematopoietic stem and progenitor cells.

The dual amylin and calcitonin receptor agonist KBP-089 and the GLP-1 receptor agonist liraglutide act complimentarily on body weight reduction and metabolic profile.

BACKGROUND: Weight loss therapy is becoming more and more important, and two classes of molecules, namely amylin receptor and GLP-1 receptor agonists, have shown promise in this regard. Interestingly, these molecules have several overlapping pharmacological effects, such as suppression of gastric emptying, reduction of glucagon secretion and weight loss in common; however, they also have distinct effects on prandial insulin secretion. Hence, a combination of these two mechanisms is of significant interest. METHODS: In this study, we investigated the add-on potential of the dual amylin and calcitonin receptor agonist (DACRA) KBP-089 in combination with the GLP-1 receptor agonist liraglutide as obesity treatment in high-fat diet (HFD) fed rats. RESULTS: Increasing doses of KBP-089 and liraglutide alone and in combination were studied with respect to their effects on body weight, food intake and glucose metabolism during a 9-week intervention study conducted in HFD rats. Further, the gastric emptying rate during an oral glucose tolerance was assessed. Treatment with KBP-089 and liraglutide dose-dependently lowered body weight 15% (at 2.5 µg/kg/day) and 7% (at 400 µg/kg/day) in HFD rats, respectively, while the combination resulted in a 21% body weight reduction, which was mirrored by reduction in fat depot sizes. Gastric emptying and glucose metabolism were improved, primarily by KBP-089, although liraglutide led to a reduction in fasting plasma glucagon. CONCLUSION: DACRAs complement GLP-1 on food intake, body weight, and glucose tolerance indicating the potential for an add-on therapy.

Treatment with a dual amylin and calcitonin receptor agonist improves metabolic health in an old, obese, and ovariectomized rat model.

OBJECTIVES: Menopause is often characterized by detrimental metabolic changes, such as obesity, insulin resistance, and impaired glucose tolerance, often requiring treatment. KeyBioscience Peptides (KBPs) are Dual Amylin and Calcitonin Receptor Agonists which have shown promising metabolic effects in rats. The objective of this study was to investigate the in vivo effect of KBP on the metabolic health in a model driven by unhealthy diet, age, and menopause. METHODS: Female Sprague Dawley rats were fed a high-fat diet (HFD) for 3 months before the initiation of the study. At 6 months of age the rats were randomized into groups (n = 12) and subjected to ovariectomy surgery and treatment with KBP: (1) Lean-Sham, (2) HFD-Sham, (3) Lean-OVX, (4) HFD-OVX, (5) HFD-OVX-KBP (10 µg/kg/d), (6) HFD-OVX-KBP (20 µg/kg/d), (7) HFD-OVX-EE2 (30 µg/d 17a-ethynylestradiol). Body weight, food intake, oral glucose tolerance tests (OGTTs), subcutaneous fat, visceral fat, liver weight, and uterus weight were assessed during the 6-month study. Statistical analyses were conducted by one-way ANOVA with Tukey post-hoc test for multiple comparisons. RESULTS: Combination of OVX and HFD led to significant induction of obesity (31% weight increase, P < 0.001) and insulin resistance (13% increase in tAUCglucose during OGTT P < 0.01) compared with the relevant control groups (P < 0.05), and this could be completely rescued by EE2 therapy confirming the model system (P < 0.05).Treatment of OVX-HFD rats with KBP for 26 weeks led to a significant reduction in body weight (13%, P < 0.001) in the high dose and 9% (P < 0.01) in the low dose, with corresponding improvements in fat depot sizes, all compared with HFD-OVX controls. As expected, food intake was suppressed, albeit mainly in the first 2 weeks of treatment, resulting in a reduction of overall caloric intake by 6.5% (P < 0.01) and 12.5% (P < 0.001) in the low and high doses respectively. Furthermore, treatment with KBP reduced the weight of visceral and subcutaneous fat tissues. Finally, KBP treatment significantly improved glucose tolerance, assessed using OGTTs at weeks 8, 16, and 24. CONCLUSIONS: The data presented here clearly indicate a positive and sustained effect of KBP treatment on body weight loss, fat depot size, and improved glucose tolerance, illustrating the potential of KBPs as treatments for metabolic complications of overweight and menopause.

Mono and dual agonists of the amylin, calcitonin, and CGRP receptors and their potential in metabolic diseases.

BACKGROUND: Therapies for metabolic diseases are numerous, yet improving insulin sensitivity beyond that induced by weight loss remains challenging. Therefore, search continues for novel treatment candidates that can stimulate insulin sensitivity and increase weight loss efficacy in combination with current treatment options. Calcitonin gene-related peptide (CGRP) and amylin belong to the same peptide family and have been explored as treatments for metabolic diseases. However, their full potential remains controversial. SCOPE OF REVIEW: In this article, we introduce this rather complex peptide family and its corresponding receptors. We discuss the physiology of the peptides with a focus on metabolism and insulin sensitivity. We also thoroughly review the pharmacological potential of amylin, calcitonin, CGRP, and peptide derivatives as treatments for metabolic diseases, emphasizing their ability to increase insulin sensitivity based on preclinical and clinical studies. MAJOR CONCLUSIONS: Amylin receptor agonists and dual amylin and calcitonin receptor agonists are relevant treatment candidates, especially because they increase insulin sensitivity while also assisting weight loss, and their unique mode of action complements incretin-based therapies. However, CGRP and its derivatives seem to have only modest if any metabolic effects and are no longer of interest as therapies for metabolic diseases.

Transcriptome sequencing identifies a noncoding, deep intronic variant in CLCN7 causing autosomal recessive osteopetrosis.

BACKGROUND: Over half of children with rare genetic diseases remain undiagnosed despite maximal clinical evaluation and DNA-based genetic testing. As part of an Undiagnosed Diseases Program applying transcriptome (RNA) sequencing to identify the causes of these unsolved cases, we studied a child with severe infantile osteopetrosis leading to cranial nerve palsies, bone deformities, and bone marrow failure, for whom whole-genome sequencing was nondiagnostic. METHODS: We performed transcriptome (RNA) sequencing of whole blood followed by analysis of aberrant transcript isoforms and osteoclast functional studies. RESULTS: We identified a pathogenic deep intronic variant in CLCN7 creating an unexpected, frameshifting pseudoexon causing complete loss of function. Functional studies, including osteoclastogenesis and bone resorption assays, confirmed normal osteoclast differentiation but loss of osteoclast function. CONCLUSION: This is the first report of a pathogenic deep intronic variant in CLCN7, and our approach provides a model for systematic identification of noncoding variants causing osteopetrosis-a disease for which molecular-genetic diagnosis can be pivotal for potentially curative hematopoietic stem cell transplantation. Our work illustrates that cryptic splice variants may elude DNA-only sequencing and supports broad first-line use of transcriptome sequencing for children with undiagnosed diseases.

The CNS-specific proteoglycan, brevican, and its ADAMTS4-cleaved fragment show differential serological levels in Alzheimer's disease, other types of dementia and non-demented controls: A cross-sectional study.

Evidence indicate that the brain-specific protein, brevican, is proteolytically cleaved during neurodegeneration, hence positioning fragments of brevican as potential blood biomarkers of neurodegenerative diseases, such as dementia. We aimed to develop two assays capable of detecting the brevican N-terminal (N-Brev) and the ADAMTS4-generated fragment (Brev-A), cleaved at Ser401, in serum and to perform a preliminary assessment of their diagnostic potential in dementias. Monoclonal antibodies against N-Brev and Brev-A were used to develop two ELISAs detecting each epitope. A comparison of brevican fragments in serum from individuals with AD (n = 28), other dementia (OD) (n = 41), and non-dementia-related memory complaints (NDCs) (n = 48) was conducted. Anti-N-Brev and anti-Brev-A antibodies selectively recognized their targets and dilution and spike recoveries were within limits of ±20%. Intra- and inter-assay CVs were below limits of 10% and 15%, respectively. For the N-Brev biomarker, serum from patients with OD showed significantly lower levels than those with AD (p = 0.05) and NDCs (p < 0.01). The opposite pattern was evident for Brev-A: serum levels in patients with OD were significantly higher than for AD (p = 0.04) and NDCs (p = 0.01). For both N-Brev and Brev-A, levels did not differ between AD and NDCs. The ratio of N-Brev/Brev-A resulted in increased significant differences between OD and AD (p < 0.01) and between OD and NDCs (p < 0.0001). The ratio discriminated between NDCs and OD (AUC: 0.75, 95% CI: 0.65-0.85, p < 0.0001) and between OD and AD (AUC: 0.72, 95% CI: 0.59-0.85, p < 0.01). In conclusion, we developed the first assays detecting the N-terminal of brevican as well as an ADAMTS4-cleaved fragment of brevican in blood. Differential levels of N-Brev and Brev-A between AD and OD allow for these biomarkers to possibly distinguish between different forms of dementias.

Generation of gene-corrected functional osteoclasts from osteopetrotic induced pluripotent stem cells.

BACKGROUND: Infantile malignant osteopetrosis (IMO) is an autosomal recessive disorder characterized by non-functional osteoclasts and a fatal outcome early in childhood. About 50% of patients have mutations in the TCIRG1 gene. METHODS: IMO iPSCs were generated from a patient carrying a homozygous c.11279G>A (IVS18+1) mutation in TCIRG1 and transduced with a lentiviral vector expressing human TCIRG1. Embryoid bodies were generated and differentiated into monocytes. Non-adherent cells were harvested and further differentiated into osteoclasts on bovine bone slices. RESULTS: Release of the bone resorption biomarker CTX-I into the media of gene-corrected osteoclasts was 5-fold higher than that of the uncorrected osteoclasts and 35% of that of control osteoclasts. Bone resorption potential was confirmed by the presence of pits on the bones cultured with gene-corrected osteoclasts, absent in the uncorrected IMO osteoclasts. CONCLUSIONS: The disease phenotype was partially corrected in vitro, providing a valuable resource for therapy development for this form of severe osteopetrosis.

The Calcitonin Receptor Plays a Major Role in Glucose Regulation as a Function of Dual Amylin and Calcitonin Receptor Agonist Therapy.

Amylin treatment improves body weight and glucose control, although it is limited by a short action and need for high doses. Dual amylin and calcitonin receptor agonists (DACRAs) are dual amylin and calcitonin receptor agonists with beneficial effects beyond those of amylin. However, to what extent the additional benefits reside in their higher potency or their targeting of the calcitonin receptor remains unclear. Here we deconstruct the receptors involved in the effects of a DACRA, KBP-088, by comparing it to rat amylin (rAMY), rat calcitonin (rCT), and their combination in obese high-fat diet (HFD) and diabetic Zucker diabetic fatty (ZDF) rats. HFD-fed Sprague-Dawley rats and ZDF rats were treated for 4 weeks with KBP-088 (5 µg/kg per day), rAMY (300 µg/kg per day), rCT (300 µg/kg per day), and the combination of rAMY and rCT (300+300 µg/kg per day) using infusion pumps. Body weight, food intake, fasting glycemia, glycated hemoglobin type A1c levels, and glucose tolerance were assessed. In obese HFD-fed rats, KBP-088, rAMY, and the combination of rAMY and rCT significantly reduced body weight and improved glucose tolerance, whereas rCT alone had no effect. In diabetic ZDF rats, rCT was efficient in lowering fasting glycemia similar to rAMY, whereas dual activation by KBP-088 and the combination of rAMY and rCT were superior to activating either receptor alone. In conclusion, calcitonin therapy regulates fasting blood glucose in a diabetic rat model, thereby underscoring the importance of calcitonin receptor activation as well as the known role of amylin receptor agonism in the potent metabolic benefits of this group of peptides. SIGNIFICANCE STATEMENT: We deconstruct the receptors activated by dual amylin and calcitonin receptor agonist (DACRA) therapy to elucidate through which receptor the beneficial metabolic effects of the DACRAs are mediated. We show that calcitonin receptor activation is important for blood glucose regulation in diabetes. This is in addition to the known metabolic beneficial role of amylin receptor activation. These data help in understanding the potent metabolic benefits of the DACRAs and underline the potential of DACRAs as treatment for diabetes and obesity.

Dose Frequency Optimization of the Dual Amylin and Calcitonin Receptor Agonist KBP-088: Long-Lasting Improvement in Food Preference and Body Weight Loss.

Dual amylin and calcitonin receptor agonists (DACRAs) are novel candidates for treatment of type 2 diabetes and obesity because of their beneficial effects on body weight, blood glucose, insulin sensitivity, and food preference, at least short-term. DACRAs activate the receptors for a prolonged time period, resulting in metabolic effects superior to those of amylin. Because of the prolonged receptor activation, different dosing intervals and, hence, less frequent receptor activation might change the efficacy of DACRA treatment in terms of weight loss and food preference. In this study, we compared daily dosing to dosing every other day with the aim of understanding the optimal balance between efficacy and tolerability. Obese and lean male Sprague-Dawley rats were treated with the DACRA KBP-088, applying two different dosing intervals (1.5 nmol/kg once daily and 3 nmol/kg every other day) to assess the effect on body weight, food intake, glucose tolerance, and food preference when given the choice between chow (13% fat) and a high-fat diet (60% fat). Treatment with KBP-088 induced significant weight loss, reduction in adiposity, improvement in glucose control, and altered food preference toward food that is less calorie-dense. KBP-088 dosed every other day (3 nmol/kg) was superior to KBP-088 once daily (1.5 nmol/kg) in terms of weight loss and improvement of food preference. The beneficial effects were evident in both lean and obese rats. Hence, dosing KBP-088 every other day positively affects overall efficacy on metabolic parameters regardless of the lean/obese state, suggesting that less-frequent dosing with KBP-088 could be feasible. SIGNIFICANCE STATEMENT: Here, we show that food preference can be altered chronically toward choices that are less calorie-dense by pharmacological treatment. Further, pharmacological dosing regimens affect the efficacy differently, as dosing every other day improved body weight loss and alterations in food preference compared with daily dosing. This suggest that alterations of the dosing regimens could be feasible in the treatment of obesity.

Hematopoietic Stem Cell-Targeted Neonatal Gene Therapy with a Clinically Applicable Lentiviral Vector Corrects Osteopetrosis in oc/oc Mice.

Infantile malignant osteopetrosis (IMO) is an autosomal recessive disorder characterized by nonfunctional osteoclasts. Approximately 50% of the patients have mutations in the TCIRG1 gene, encoding for a subunit of the osteoclast proton pump. Gene therapy represents a potential alternative treatment to allogeneic stem cell transplantation for IMO. The oc/oc mouse is a model of IMO characterized by a 1,500 bp deletion in the TCIRG1 gene, severe osteopetrosis, and a life span of only 3 weeks. Here we show that the osteopetrotic phenotype in oc/oc mice can be reversed by hematopoietic stem cell-targeted gene therapy with a clinically applicable lentiviral vector expressing a wild-type form of human TCIRG1 under the mammalian promoter elongation factor 1α short (EFS-hT). oc/oc c-kit+ fetal liver cells transduced with EFS-hT were transplanted into sublethally irradiated oc/oc mice by temporal vein injection 1 day after birth. A total of 9 of 12 mice survived long term (19-25 weeks) with evidence of tooth eruption, uncharacteristic of oc/oc mice. Splenocytes were harvested 19-25 weeks after transplantation and differentiated into osteoclasts on bone slices to assess resorption and on plastic to assess TCIRG1 protein expression. Vector-corrected osteoclasts showed human TCIRG1 expression by Western blot. CTX-I release relative to that mediated by oc/oc-derived osteoclasts increased 8-239-fold. Resorption pits on bone slices were observed for osteoclasts derived from 7/9 surviving transplanted oc/oc mice. Histopathology of the bones of surviving animals showed varying degrees of rescued phenotype, the majority with almost full correction. The average vector copy number per cell in the bone marrow was 1.8 ± 0.5. Overall, 75% of transplanted mice exhibited long-term survival and marked reversal of the osteopetrotic bone phenotype. These findings represent a significant step toward the clinical application of gene therapy for IMO.

The Dual Amylin and Calcitonin Receptor Agonist KBP-088 Induces Weight Loss and Improves Insulin Sensitivity Superior to Chronic Amylin Therapy.

KBP-088 (KeyBiosciencePeptide 088) is a potent dual amylin and calcitonin receptor agonist (DACRA). DACRAs are known to elicit potent activity in terms of typical amylin-induced responses, such as reducing food intake and body weight. However, to what extent amylin infusion can mimic the effects of the dual agonist KBP-088 is unknown. We studied the effect of acute dosing with KBP-088 (5 µg/kg) and rat amylin (100, 300, and 1000 µg/kg) and subsequently compared the chronic effect of KBP-088 (5 µg/kg per day) to increasing doses of rat amylin (100, 300, and 1000 µg/kg per day) delivered by continuous subcutaneous infusion, in high-fat diet (HFD) fed Long-Evans rats. Furthermore, acute amylin sensitivity was investigated. Single dose KBP-088 (5 µg/kg) potently reduced acute food intake for a prolonged period compared with amylin (100, 300, and 1000 µg/kg), confirming the difference in potency. Independent of dose, chronic amylin administration (100, 300, and 1000 µg/kg per day) was less effective than KBP-088 (5 µg/kg per day) in inducing body weight loss (15% with KBP-088, and 5%, 9%, and 8% with amylin, vehicle corrected) and reducing overall adiposity in HFD rats. Moreover, KBP-088 improved oral glucose tolerance with significantly reduced insulin levels (80% reduction) that were better than all doses of amylin (68%, 53%, and 7% reduction). Acute amylin sensitivity was independent of the chronic treatment. Dual activation of amylin and calcitonin receptors by KBP-088 is superior to amylin in reducing body weight and improving glucose tolerance, indicating a role for the calcitonin receptor.

GPDPLQ1237-A Type II Collagen Neo-Epitope Biomarker of Osteoclast- and Inflammation-Derived Cartilage Degradation in vitro.

C-telopeptide of type II collagen (CTX-II) has been shown to be a highly relevant biomarker of cartilage degradation in human rheumatic diseases, if measured in synovial fluid or urine. However, serum or plasma CTX-II have not been demonstrated to have any clinical utility to date. Here, we describe the GPDPLQ1237 ELISA which targets the EKGPDPLQ↓ neo-epitope, an elongated version of the CTX-II neo-epitope (EKGPDP↓), speculated to be a blood-precursor of CTX-II generated by the cysteine protease cathepsin K. Human osteoclast cartilage resorption cultures as well as oncostatin M and tumour necrosis factor α-stimulated bovine cartilage explant cultures were used to validate GPDPLQ1237 biologically by treating the cultures with the cysteine protease inhibitor E-64 and/or the matrix metalloproteinase (MMP) inhibitor GM6001 to assess the potential contributions of these two protease classes to GPDPLQ1237 release. Cartilage resorption-derived GPDPLQ1237 release was inhibited by E-64 (72.1% inhibition), GM6001 (75.5%), and E-64/GM6001 (91.5%), whereas CTX-II release was inhibited by GM6001 (87.0%) but not by E-64 (5.5%). Cartilage explant GPDPLQ1237 and CTX-II release were both fully inhibited by GM6001 but were not inhibited by E-64. No clinically relevant GPDPLQ1237 reactivity was identified in human serum, plasma, or urine from healthy donors or arthritis patients. In conclusion, the GPDPLQ1237 biomarker is released during osteoclast-derived cysteine protease- and MMP-mediated cartilage degradation in vitro, whereas CTX-II release is mediated by MMPs and not by cysteine proteases, as well as from MMP-mediated cartilage degradation under a pro-inflammatory stimulus. These findings suggest that GPDPLQ1237 may be relevant in diseases with pathological osteoclast activity and cartilage degradation. Further studies are required to validate the neo-epitope in human samples.