Therapeutic efficacies of mitochondria-targeted esculetin and metformin in the improvement of age-associated atherosclerosis via regulating AMPK activation

Atherosclerosis, in general, is an age-associated cardiovascular disease wherein a progressive decline in mitochondrial function due to aging majorly contributes to the disease development. Mitochondria-derived ROS due to dysregulated endothelial cell function accentuates the progression of atherosclerotic plaque formation. To circumvent this, mitochondrially targeted antioxidants are emerging as potential candidates to combat metabolic abnormalities. Recently, we synthesized an alkyl TPP+ tagged esculetin (Mito-Esc), and in the current study, we investigated the therapeutic efficacies of Mito-Esc and metformin, a well-known anti-diabetic drug, in the amelioration of age-associated plaque formation in the aortas of 12 months aged Apoe-/- and 20 months aged C57BL/6 mice, in comparison to young C57BL/6 control mice. Administration of Mito-Esc or metformin significantly reduced age-induced atherosclerotic lesion area, macrophage polarization, vascular inflammation, and senescence. Further, chronic passaging of human aortic endothelial cells (HAEC) with either Mito-Esc or metformin significantly delayed cellular senescence via the activation of the AMPK-SIRT1/SIRT6 axis. Conversely, depletion of either AMPK/SIRT1/SIRT6 caused premature senescence. Consistent with this, Mito-Esc or metformin treatment attenuated NFkB-mediated inflammatory signaling and enhanced ARE-mediated anti-oxidant responses in comparison to late passage control HAECs. Importantly, culturing of HAECs for several passages with either Mito-Esc or metformin significantly improved mitochondrial function. Overall, Mito-Esc and metformin treatments delay age-associated atherosclerosis by regulating vascular senescence via the activation of AMPK-SIRT1/SIRT6 axis.

Mitochondria-targeted esculetin and metformin delay endothelial senescence by promoting fatty acid β-oxidation: Relevance in age-associated atherosclerosis

Impaired mitochondrial fatty acid β-oxidation (FAO) plays a role in the onset of several age-associated diseases, including atherosclerosis. In the current work, we investigated the efficacies of mitochondria-targeted esculetin (Mito-Esc) and metformin in enhancing FAO in human aortic endothelial cells (HAECs), and its relevance in the delay of cellular senescence and age-associated atherosclerotic plaque formation in Apoe-/- mice. Chronic culturing of HAECs with either Mito-Esc or metformin increased oxygen consumption rates (OCR), and caused delay in senescence features. Conversely, etomoxir (CPT1 inhibitor) reversed Mito-Esc- and metformin-induced OCR, and caused premature endothelial senescence. Interestingly, Mito-Esc, unlike metformin, in the presence of etomoxir failed to preserve OCR. Thereby, underscoring Mito-Esc's exclusive reliance on FAO as an energy source. Mechanistically, chronic culturing of HAECs with either Mito-Esc or metformin led to AMPK activation, increased CPT1 activity, and acetyl-CoA levels along with a concomitant reduction in malonyl-CoA levels, and lipid accumulation. Similar results were observed in Apoe-/- mice aorta and liver tissue with a parallel reduction in age-associated atherosclerotic plaque formation and degeneration of liver with either Mito-Esc or metformin administration. Together, Mito-Esc and metformin by potentiating FAO, may have a role in the delay of cellular senescence by modulating mitochondrial function.

Therapeutic efficacy of mitochondria-targeted esculetin in the improvement of NAFLD-NASH via modulating AMPK-SIRT1 axis

Mitochondrial dysfunction due to deregulated production of mitochondria-derived ROS is implicated in the development and progression of non-alcoholic fatty liver disease (NAFLD) to non-alcoholic steatohepatitis (NASH). Recently, we synthesized a novel mitochondria-targeted esculetin (Mito-Esc) and investigated its dose-response therapeutic efficacy in mitigating high-fat diet (HFD)-induced NAFLD and NASH in Apoe-/- mice. Mito-Esc administration, compared to simvastatin and pioglitazone, dose-dependently caused a significant reduction in body weight, improved lipid profile, glucose homeostasis, and pro-inflammatory cytokines level. Mito-Esc administration reduced adipose tissue hypertrophy and lipid accumulation presumably by regulating the levels of CD36, PPAR-γ, EBP-α, and their target genes. Mechanistically, Mito-Esc-induced activation of the AMPK1α-SIRT1 axis inhibited pre-adipocyte differentiation. Conversely, Mito-Esc failed to regulate pre-adipocyte differentiation under AMPK/SIRT1 depleted conditions. In parallel, Mito-Esc administration ameliorated HFD-induced steatosis, fibrosis of the liver, and NAFLD-associated atheromatous plaque formation in the aorta. Importantly, Mito-Esc administration inhibited HFD-induced infiltration of macrophages, a marker of steatohepatitis, in the adipose and liver tissues. The results of the in vitro studies showed that Mito-Esc treatment significantly inhibits TGF-β-induced hepatic stellate cell differentiation as well as the fibrotic markers. Consistent with the above observations, Mito-Esc treatment by activating the AMPK-SIRT1 pathway markedly reversed palmitate-induced mitochondrial superoxide production, depolarization of mitochondrial membrane potential, and lipid accumulation in HepG2 cells. Together, the therapeutic efficacy of Mito-Esc in the mitigation of HFD-induced lipotoxicity, and the associated NASH is in part, mediated by potentiating the AMPK-SIRT1 axis.

In vivo and in vitro characterization of GL0034, a novel long-acting glucagon-like peptide-1 receptor agonist

AIMS

To describe the in vitro characteristics and antidiabetic in vivo efficacy of the novel glucagon-like peptide-1 receptor agonist (GLP-1RA) GL0034.

MATERIALS AND METHODS

Glucagon-like peptide-1 receptor (GLP-1R) kinetic binding parameters, cyclic adenosine monophosphate (cAMP) signalling, endocytosis and recycling were measured using HEK293 and INS-1832/3 cells expressing human GLP-1R. Insulin secretion was measured in vitro using INS-1832/3 cells, mouse islets and human islets. Chronic administration studies to evaluate weight loss and glycaemic effects were performed in db/db and diet-induced obese mice.

RESULTS

Compared to the leading GLP-1RA semaglutide, GL0034 showed increased binding affinity and potency-driven bias in favour of cAMP over GLP-1R endocytosis and β-arrestin-2 recruitment. Insulin secretory responses were similar for both ligands. GL0034 (6 nmol/kg) led to at least as much weight loss and lowering of blood glucose as did semaglutide at a higher dose (14 nmol/kg).

CONCLUSIONS

GL0034 is a G protein-biased agonist that shows powerful antidiabetic effects in mice, and may serve as a promising new GLP-1RA for obese patients with type 2 diabetes.

A functional and self-assembling octyl-phosphonium-tagged esculetin as an effective siRNA delivery agent

Herein, we document a self-assembling octyl-TPP tagged esculetin (Mito-Esc) as functionally active and as a novel small molecule siRNA delivery vector. While Mito-Esc itself induces selective breast cancer cell death, the amphiphilic nature of Mito-Esc delivers therapeutic siRNAs intracellularly without the need for any excipient to exacerbate the anti-proliferative effects.

Analytical characterization of recombinant hCG and comparative studies with reference product

INTRODUCTION

Regulatory agencies recommend a stepwise approach for demonstrating biosimilarity between a proposed biosimilar and reference biological product emphasizing for functional and structural characterization to trace if there is any difference which may impact safety and efficacy. We studied the comparative structural and biological attributes of recombinant human chorionic gonadotropin (rhCG), SB005, with reference product, Ovidrel® and Ovitrelle®. Recombiant hCG was approved in 2000 by the US Food and Drug Administration for the induction of final follicular maturation, early luteinization in infertile women as part of assisted reproductive technology program. It is also indicated for the induction of ovulation and pregnancy in ovulatory infertile patients whose cause of infertility is not due to ovarian failure.

MATERIALS AND METHODS

Primary structure was studied by intact mass analysis, peptide fingerprinting, peptide mass fingerprinting and sequence coverage analysis. Higher order structure was studied by circular dichroism, ultraviolet-visible spectroscopy, fluorescence spectroscopy, and disulfide bridge analysis. Different isoforms of reference product and SB005 were identified using capillary isoelectric focusing and capillary zone electrophoresis. Glycosylation was studied by N-glycan mapping using LC-ESI-MS, point of glycosylation, released glycan analysis using ultra performance liquid chromatography and sialic acid analysis. Product related impurities such as oligomer content analysis and oxidized impurities were studied using size exclusion chromatography and reverse phase high performance liquid chromatography, respectively. Biological activity in term of potency of reference product and SB005 was studied by in vivo analysis.

RESULTS AND CONCLUSION

In this study we have compared analytical similarity of recombinant rhCG (SB005) produced at Sun Pharmaceuticals with the reference product with respect to its primary, higher order structure, isoforms, charge variants, glycosylation, sialyation pattern, pharmacodynamic and in vivo efficacy. Our studies show that the in house produced rhCG has a high degree of structural and functional similarity with the reference product available in the market.

Lipodox® (generic doxorubicin hydrochloride liposome injection): in vivo efficacy and bioequivalence versus Caelyx® (doxorubicin hydrochloride liposome injection) in human mammary carcinoma (MX-1) xenograft and syngeneic fibrosarcoma (WEHI 164) mouse models

Background

Doxorubicin (DXR) hydrochloride (HCl) liposome injection is an important part of the treatment armamentarium for a number of cancers. With growing needs for affordable and effective anticancer treatments, the development of generics is becoming increasingly important to facilitate patient access to vital medications. We conducted studies in relevant mouse models of cancer to compare the preclinical antitumour efficacy and plasma pharmacokinetic profile of a proposed generic DXR HCl liposome injection developed by Sun Pharmaceutical Industries Ltd. (SPIL DXR HCl liposome injection) with Caelyx® (reference DXR HCl liposome injection).

Methods

Syngeneic fibrosarcoma (WEHI 164)-bearing BALB/c mice and athymic nude mice transplanted with MX-1 human mammary carcinoma xenografts were treated with SPIL DXR HCl liposome injection, reference DXR HCl liposome injection or placebo, to compare tumour volume, antitumour activity (percentage test/control [%T/C] ratio, tumour regression, and specific tumour growth delay) and toxicity (survival and weight changes) in response to treatment. The pharmacokinetic profile of the SPIL and reference product was also studied in syngeneic fibrosarcoma-bearing mice.

Results

Treatment with either SPIL or reference DXR HCl liposome injection resulted in significant reduction in tumour volume from baseline in both models at all doses tested. High antitumour activity (%T/C ≤ 10) was seen from Day 21 and Day 14 onwards in SPIL and reference DXR HCl liposome injection–treated syngeneic fibrosarcoma-bearing mice, respectively, at 9 mg/kg. Moderate antitumour activity (%T/C ≤ 20) was seen from Day 17 and Day 24 onwards in SPIL and reference DXR HCl liposome injection–treated MX-1-bearing mice, respectively, at 6 mg/kg. No significant differences in tumour volume and %T/C were observed between SPIL and reference DXR HCl liposome injection–treated groups at any dose (p ≥ 0.05). Toxicity profiles were considered to be generally comparable. Evaluation of test/reference (A/B) ratios and 90% confidence intervals (CIs) for peak serum concentration (C_max) and area under the curve (AUC_0-t, and AUC_0-∞) demonstrated bioequivalence of SPIL and reference DXR HCl liposome injections.

Conclusions

Establishing similarity is of critical importance during the development of generic treatments. SPIL and reference DXR HCl liposome injections were shown to be comparable with regards to antitumour activity, toxicity and pharmacokinetics.

Synthesis, preliminary biological evaluation and molecular modeling of some new heterocyclic inhibitors of TACE

Central heteroaryl ring analogues belonging to a series of potent hydroxamate TACE inhibitors were synthesized. The TACE inhibitory activities of these compounds were evaluated by in vitro WBA and in silico molecular modeling studies using crystal structure of human TACE. Compound 14 showed very good in vitro inhibition, supported by the in silico docking studies.

Validation of guinea pig model of allergic rhinitis by oral and topical drugs

Ovalbumin-induced guinea pig model of rhinitis was assessed for its utility in the studies of rhinitis. Systemic sensitization and challenge with ovalbumin-induced rhinitis symptoms and an increase in anti-OVA-IgE and IgG titers, positive skin reactions and nasal lavage IL-4 concentration. Histopathology of nasal mucosa showed infiltration of eosinophils and other inflammatory cells consistent with the symptoms. Topical sensitization of ovalbumin yielded inconsistent symptoms of rhinitis. In systemic sensitization model, repeated challenge of ovalbumin caused similar response for at least 3 consecutive challenges. The symptoms were affected by relative humidity in the air and dosing volume of topical drugs. Sneezing and lacrimation were reduced by acute oral administration of the H1 receptor antagonists and steroids or the prophylactic oral administration of cysteinyl leukotriene (CysLT1) receptor antagonist montelukast or acute topical antihistamines, mast cell stabilizer sodium cromoglycate and anticholinergic agent ipratropium bromide, but not by a topical steroid. Nose rubbing was reduced significantly by some oral and topical antihistamines. Oral steroids offered excellent protection against all symptoms. Dexamethasone and montelukast also inhibited nasal lavage IL-4 concentration and inflammatory cell infiltration. Treatment with topical steroid fluticasone for 2 weeks had no effect on sneezing or rubbing. However, it caused complete inhibition of congestion. The cyclooxygenase inhibitor indomethacin had no effect on symptoms of rhinitis. The adrenergic alpha receptor agonist-decongestant oxymetazoline caused reduction in congestion. These results suggest that differential responsiveness to symptoms of rhinitis by a new agent can be very well profiled in the model in congruence with the mediation pathways and mechanism of action of drugs. The model provides complete symptomatic characterization of rhinitis and is a good tool for its study.