High throughput in vivo phenotypic screening for drug repurposing: Discovery of MLR-1023 a novel insulin sensitizer and novel Lyn kinase activator with clinical proof of concept

Investigation of SAMD1 ablation in mice

SAM domain-containing protein 1 (SAMD1) has been implicated in atherosclerosis, as well as in chromatin and transcriptional regulation, suggesting a versatile and complex biological function. However, its role at an organismal level is currently unknown. Here, we generated SAMD1^-/- and SAMD1^+/- mice to explore the role of SAMD1 during mouse embryogenesis. Homozygous loss of SAMD1 was embryonic lethal, with no living animals seen after embryonic day 18.5. At embryonic day 14.5, organs were degrading and/or incompletely developed, and no functional blood vessels were observed, suggesting failed blood vessel maturation. Sparse red blood cells were scattered and pooled, primarily near the embryo surface. Some embryos had malformed heads and brains at embryonic day 15.5. In vitro, SAMD1 absence impaired neuronal differentiation processes. Heterozygous SAMD1 knockout mice underwent normal embryogenesis and were born alive. Postnatal genotyping showed a reduced ability of these mice to thrive, possibly due to altered steroidogenesis. In summary, the characterization of SAMD1 knockout mice suggests a critical role of SAMD1 during developmental processes in multiple organs and tissues.

New Horizons: Emerging Antidiabetic Medications

Over the past century, since the discovery of insulin, the therapeutic offer for diabetes has grown exponentially, in particular for type 2 diabetes (T2D). However, the drugs in the diabetes pipeline are even more promising because of their impressive antihyperglycemic effects coupled with remarkable weight loss. An ideal medication for T2D should target not only hyperglycemia but also insulin resistance and obesity. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and the new class of GLP1 and gastric inhibitory polypeptide dual RAs counteract 2 of these metabolic defects of T2D, hyperglycemia and obesity, with stunning results that are similar to the effects of metabolic surgery. An important role of antidiabetic medications is to reduce the risk and improve the outcome of cardiovascular diseases, including coronary artery disease and heart failure with reduced or preserved ejection fraction, as well as diabetic nephropathy, as shown by SGLT2 inhibitors. This review summarizes the main drugs currently under development for the treatment of type 1 diabetes and T2D, highlighting their strengths and side effects.

Trends in Antidiabetic Drug Discovery: FDA Approved Drugs, New Drugs in Clinical Trials and Global Sales

Type 2 diabetes mellitus (T2DM) continues to be a substantial medical problem due to its increasing global prevalence and because chronic hyperglycemic states are closely linked with obesity, liver disease and several cardiovascular diseases. Since the early discovery of insulin, numerous antihyperglycemic drug therapies to treat diabetes have been approved, and also discontinued, by the United States Food and Drug Administration (FDA). To provide an up-to-date account of the current trends of antidiabetic pharmaceuticals, this review offers a comprehensive analysis of the main classes of antihyperglycemic compounds and their mechanisms: insulin types, biguanides, sulfonylureas, meglitinides (glinides), alpha-glucosidase inhibitors (AGIs), thiazolidinediones (TZD), incretin-dependent therapies, sodium-glucose cotransporter type 2 (SGLT2) inhibitors and combinations thereof. The number of therapeutic alternatives to treat T2DM are increasing and now there are nearly 60 drugs approved by the FDA. Beyond this there are nearly 100 additional antidiabetic agents being evaluated in clinical trials. In addition to the standard treatments of insulin therapy and metformin, there are new drug combinations, e.g., containing metformin, SGLT2 inhibitors and dipeptidyl peptidase-4 (DPP4) inhibitors, that have gained substantial use during the last decade. Furthermore, there are several interesting alternatives, such as lobeglitazone, efpeglenatide and tirzepatide, in ongoing clinical trials. Modern drugs, such as glucagon-like peptide-1 (GLP-1) receptor agonists, DPP4 inhibitors and SGLT2 inhibitors have gained popularity on the pharmaceutical market, while less expensive over the counter alternatives are increasing in developing economies. The large heterogeneity of T2DM is also creating a push towards more personalized and accessible treatments. We describe several interesting alternatives in ongoing clinical trials, which may help to achieve this in the near future.

MLR-1023 Treatment in Mice and Humans Induces a Thermogenic Program, and Menthol Potentiates the Effect

A glucose-lowering medication that acts by a different mechanism than metformin, or other approved diabetes medications, can supplement monotherapies when patients fail to meet blood glucose goals. We examined the actions underlying the effects of an insulin sensitizer, tolimidone (MLR-1023) and investigated its effects on body weight. Diet-induced obesity (CD1/ICR) and type 2 diabetes (db/db) mouse models were used to study the effect of MLR-1023 on metabolic outcomes and to explore its synergy with menthol. We also examined the efficacy of MLR-1023 alone in a clinical trial (NCT02317796), as well as in combination with menthol in human adipocytes. MLR-1023 produced weight loss in humans in four weeks, and in mice fed a high-fat diet it reduced weight gain and fat mass without affecting food intake. In human adipocytes from obese donors, the upregulation of Uncoupling Protein 1, Glucose (UCP)1, adiponectin, Glucose Transporter Type 4 (GLUT4), Adipose Triglyceride Lipase (ATGL), Carnitine palmitoyltransferase 1 beta (CPT1β), and Transient Receptor Potential Melastin (TRPM8) mRNA expression suggested the induction of thermogenesis. The TRPM8 agonist, menthol, potentiated the effect of MLR-1023 on the upregulation of genes for energy expenditure and insulin sensitivity in human adipocytes, and reduced fasting blood glucose in mice. The amplification of the thermogenic program by MLR-1023 and menthol in the absence of adrenergic activation will likely be well-tolerated, and bears investigation in a clinical trial.

Emerging Kinase Therapeutic Targets in Pancreatic Ductal Adenocarcinoma and Pancreatic Cancer Desmoplasia

Kinase drug discovery represents an active area of therapeutic research, with previous pharmaceutical success improving patient outcomes across a wide variety of human diseases. In pancreatic ductal adenocarcinoma (PDAC), innovative pharmaceutical strategies such as kinase targeting have been unable to appreciably increase patient survival. This may be due, in part, to unchecked desmoplastic reactions to pancreatic tumors. Desmoplastic stroma enhances tumor development and progression while simultaneously restricting drug delivery to the tumor cells it protects. Emerging evidence indicates that many of the pathologic fibrotic processes directly or indirectly supporting desmoplasia may be driven by targetable protein tyrosine kinases such as Fyn-related kinase (FRK); B lymphoid kinase (BLK); hemopoietic cell kinase (HCK); ABL proto-oncogene 2 kinase (ABL2); discoidin domain receptor 1 kinase (DDR1); Lck/Yes-related novel kinase (LYN); ephrin receptor A8 kinase (EPHA8); FYN proto-oncogene kinase (FYN); lymphocyte cell-specific kinase (LCK); tec protein kinase (TEC). Herein, we review literature related to these kinases and posit signaling networks, mechanisms, and biochemical relationships by which this group may contribute to PDAC tumor growth and desmoplasia.

Drug Screening and Drug Repositioning as Promising Therapeutic Approaches for Spinal Muscular Atrophy Treatment

Spinal muscular atrophy (SMA) is the most common genetic disease affecting infants and young adults. Due to mutation/deletion of the survival motor neuron (SMN) gene, SMA is characterized by the SMN protein lack, resulting in motor neuron impairment, skeletal muscle atrophy and premature death. Even if the genetic causes of SMA are well known, many aspects of its pathogenesis remain unclear and only three drugs have been recently approved by the Food and Drug Administration (Nusinersen-Spinraza; Onasemnogene abeparvovec or AVXS-101-Zolgensma; Risdiplam-Evrysdi): although assuring remarkable results, the therapies show some important limits including high costs, still unknown long-term effects, side effects and disregarding of SMN-independent targets. Therefore, the research of new therapeutic strategies is still a hot topic in the SMA field and many efforts are spent in drug discovery. In this review, we describe two promising strategies to select effective molecules: drug screening (DS) and drug repositioning (DR). By using compounds libraries of chemical/natural compounds and/or Food and Drug Administration-approved substances, DS aims at identifying new potentially effective compounds, whereas DR at testing drugs originally designed for the treatment of other pathologies. The drastic reduction in risks, costs and time expenditure assured by these strategies make them particularly interesting, especially for those diseases for which the canonical drug discovery process would be long and expensive. Interestingly, among the identified molecules by DS/DR in the context of SMA, besides the modulators of SMN2 transcription, we highlighted a convergence of some targeted molecular cascades contributing to SMA pathology, including cell death related-pathways, mitochondria and cytoskeleton dynamics, neurotransmitter and hormone modulation.