Metformin Effects on SHIP2, AMPKs and Gut Microbiota: Recent Updates on Pharmacology

INTRODUCTION

Metformin, a biguanide on the WHO's list of essential medicines has a long history of 50 years or more in treating hyperglycemia, and its therapeutic saga continues beyond diabetes treatment. Glucoregulatory actions are central to the physiological effects of metformin; surprisingly, the precise mechanism with which metformin regulates glucose metabolism is not thoroughly understood yet.

METHOD

The main aim of this review is to explore the recent implications of metformin in hepatic gluconeogenesis, AMPKs, and SHIP2 and subsequently to elucidate the metformin action across intestine and gut microbiota. We have searched PubMed, google scholar, Medline, eMedicine, National Library of Medicine (NLM), clinicaltrials.gov (registry), and ReleMed for the implications of metformin with its updated role in AMPKs, SHIP2, and hepatic gluoconeogenesis, and gut microbiota. In this review, we have described the efficacy of metformin as a drug repurposing strategy in modulating the role of AMPKs and lysosomal-AMPKs, and controversies associated with metformin.

RESULT

Research suggests that biguanide exhibits hormetic effects depending on the concentrations used (micromolar to millimolar). The primary mechanism attributed to metformin action is the inhibition of mitochondrial complex I, and subsequent reduction of cellular energy state, as observed with increased AMP or ADP ratio, thereby metformin can also activate the cellular energy sensor AMPK to inhibit hepatic gluconeogenesis. However, new mechanistic models have been proposed lately to explain the pleiotropic actions of metformin; at low doses, metformin can activate lysosomal-AMPK via the AXIN-LKB1 pathway. Conversely, in an AMPK-independent mechanism, metformin-induced elevation of AMP suppresses adenylate cyclase and glucagon-activated cAMP production to inhibit hepatic glucose output by glucagon. Metformin inhibits mitochondrial glycerophosphate dehydrogenase; mGPDH, and increases the cytosolic NADH/NAD+, affecting the availability of lactate and glycerol for gluconeogenesis. Metformin can inhibit Src homology 2 domain-containing inositol 5-phosphatase 2; SHIP2 to increase the insulin sensitivity and glucose uptake by peripheral tissues.

CONCLUSION

In addition, new exciting mechanisms suggest the role of metformin in promoting beneficial gut microbiome and gut health; metformin regulates duodenal AMPK activation, incretin hormone secretion, and bile acid homeostasis to improve intestinal glucose absorption and utilization.

Salicylic acid derivatives as potential anti asthmatic agents using disease responsive drug delivery system for prophylactic therapy of allergic asthma

Asthma is a multi-factorial and complicated lung disorder of the immune system which has expanded to a wider ambit unveiling its etiology to be omnipresent at both ends of the spectrum involving basic pharmacology and in-depth immunology. As asthma occurs through triggered activation of various immune cells due to different stimuli, it poses a great challenge to uncover specific targets for therapeutic interventions. Recent pharmacotherapeutic approaches for asthma have been focused on molecular targeting of transcription factors and their signaling pathways; mainly nucleus factor kappa B (NFκB) and its associated pathways which orchestrate the synthesis of pro-inflammatory cytokines (IL-1β, TNF-α, GM-CSF), chemokines (RANTES, MIP-1a, eotaxin), adhesion molecules (ICAM-1, VCAM-1) and inflammatory enzymes (cyclooxygenase-2 and iNOS). 5-aminosalicylic acid (5-ASA) and sodium salicylate are known to suppress NFκB activation by inhibiting inhibitor of kappa B kinase (IKκB). In order to target the transcription factor, a suitable carrier system for delivering the drug to the intracellular space is essential. 5-ASA and sodium salicylate loaded liposomes incorporated into PEG-4-acrylate and CCRGGC microgels (a polymer formed by crosslinking of trypsin sensitive peptide and PEG-4-acrylate) could probably suit the needs for developing a disease responsive drug delivery system which will serve as a prophylactic therapy for asthmatic patients.

Serum levels of IL-10, IL-17F and IL-33 in patients with asthma: a case-control study

OBJECTIVES

The development of inflammation in asthma involves an intricate network of cytokines that recruit and activate numerous immune cells. This study was aimed to compare serum levels of IL-10, IL-17F, and IL-33 in asthmatic patients and non-asthmatic controls and correlate cytokine levels to asthma severity and various clinical, spirometric, and laboratory variables.

METHODS

Using ELISA, serum levels of IL-10, IL-17F, and IL-33 were evaluated in 44 asthmatics (14 mild persistent, 15 moderate persistent, and 15 severe persistent) and 44 controls.

RESULTS

This is one of the first reports showing a significant difference in serum levels of asthma-associated cytokines, anti-inflammatory IL-10, and pro-inflammatory IL-17F and IL-33, in the same subset of asthmatic patients. Our results showed diminished level of IL-10 and elevated levels of IL-17F and IL-33 in asthmatics than in controls (p < 0.001). Assessment of cytokine levels between subjects of different gender, age group, and BMI showed non-significant differences. Correlation analysis of cytokine levels to clinical variables showed that IL-17F is associated negatively to FVC % predicted (forced vital capacity) and FEV1% predicted (forced expiratory volume in one second) and positively to number of allergens sensitized and FEV1 reversibility. A strong negative correlation was found between IL-10 and IL-33 levels (p = 0.001).

CONCLUSIONS

Negative correlation between IL-10 and IL-33 levels may reflect a converse relationship between anti-inflammatory and pro-inflammatory cytokines in an individually balanced pattern. The association between IL-17F level and asthmatic phenotypes such as reduced FVC and FEV1, higher degree of sensitization, and post-bronchodilator reversibility needs further assessments.