Investigation of HCAR2 antagonists as a potential strategy to modulate bovine leukocytes.

BACKGROUND: Dairy cows experiencing ketosis after calving suffer greater disease incidence and are at greater risk of leaving the herd. In vitro administration of beta-hydroxybutyric acid (BHBA; the primary blood ketone) has inhibitory effects on the function of bovine leukocytes. BHBA is a ligand of HCAR2 and the activation of these receptors promotes an anti-inflammatory response which may be related with immunosuppression observed in transition dairy cattle. The objective of this study was to identify and test antagonists for HCAR2 in bovine immune cells cultured with BHBA. RESULTS: We observed expression of HCAR2 at the protein level within lymphocytes, monocytes, and granulocytes. The proportion of cells expressing HCAR2 tended to be greater in mid-lactation compared to early lactation cows; the increase was a result of increased proportion of T and B cells expressing HCAR2. Stimulation of HCAR2 with niacin or BHBA promoted Ca2+ mobilization in neutrophils and mononuclear cells. Mononuclear cells treated with BHBA had diminished intracellular Ca2+ responses when HCAR2 was knocked down by siRNA silencing, indicating Ca2+ mobilization was mediated by HCAR2 signaling. Two candidate antagonists for HCAR2, synthesized from niacin (NA-1 and NA-5), were tested; monocytes and neutrophils pre-treated with NA-1 and NA-5 had reduced Ca2+ mobilization after incubation with BHBA. Furthermore, NA-5 but not NA-1 prevented BHBA-associated reductions in cyclic AMP. CONCLUSIONS: We demonstrated that HCAR2 is present on bovine leukocytes and has greater expression later in lactation. We confirmed that BHBA and niacin derived HCAR2 antagonists alter bovine leukocyte activity. Our results demonstrate that both BHBA and niacin affect bovine leukocyte Ca2+ mobilization in a HCAR2-dependent manner.

Recent advance on PTP1B inhibitors and their biomedical applications.

Protein Tyrosine Phosphatase 1B (PTP1B), as one of the most important members in PTP superfamily, plays a vital role in conducting various cellular functions. So far, PTP1B has been reported to be involved in the development of many diseases including obesity, diabetes, cancers and cardiovascular diseases. Development of potent and specific PTP1B inhibitors and studies on the structure-activity relationship (SAR) between their chemical structures and their biological activity have drawn increasing attention as they could not only modulate the PTP1B functions inside the cells but also provide useful lead compounds for the treatment of various PTP1B-associated diseases. To this end, we herein summarized the recent developments of PTP1B inhibitors, and different kinds of high-throughput screening strategies for the identification of potential PTP1B inhibitors as well as their potential biomedical applications, and we also provided some perspectives in the concluding remarks in this work.

Accuracy of Glucose Meter among Adults in a Semi-urban Area in Kathmandu, Nepal.

INTRODUCTION: Glucose meters are gaining popularity in monitoring of blood glucose at household levels and in health care set-ups due to their portability, affordability and convenience of use over the laboratory based reference methods. Still they are not free of limitations. Operator's technique, extreme temperatures, humidity, patients' medication, hematocrit values can affect the reliability of glucose meter results. Hence, the accuracy of glucose meter has been the topic of concern since years. Therefore, present study aims to evaluate the analytical and clinical accuracy of glucose meter using International Organization for Standardization 15197 guideline. METHODS: A community based descriptive cross-sectional study was conducted in Kapan, Kathmandu, Nepal in April 2018. Glucose levels were measured using glucose meter and reference laboratory method simultaneously among 203 adults ≥20 years, after an overnight fasting and two hours of ingestion of 75 grams glucose. Modified Bland-Altman plots were created by incorporating ISO 15197 guidelines to check the analytical accuracy and Park error grid was used to evaluate the clinical accuracy of the device. RESULTS: Modified Bland-Altman plots showed>95% of the test results were beyond the acceptable analytical criteria of ISO 15197:2003 and 2013. Park Error Grid-Analysis showed 99% of the data within zones A and B of the consensus error grid. CONCLUSIONS: Glucose meter readings were within clinically acceptable parameters despite discrepancies on analytical merit. Possible sources of interferences must be avoided during the measurement to minimize the disparities and the values should be interpreted with caution.

Inhibition of Acyl-CoA: cholesterol acyltransferase (ACAT), overexpression of cholesterol transporter gene, and protection of amyloid ß (Aß) oligomers-induced neuronal cell death by tricyclic pyrone molecules.

A major effort in Alzheimer's disease therapeutic development has targeted Aß and downstream events. We have synthesized a small library of tricyclic pyrone compounds. Their protective action in MC65 cells and inhibition of ACAT along with the upregulation of cholesterol transporter gene were investigated. Five active compounds exhibited potencies in the nanomolar ranges. The multiple effects of the compounds on Aß and cellular cholesterol pathways could be potential mechanisms underlying the protective effects in vivo.

Synthesis and anti-norovirus activity of pyranobenzopyrone compounds.

During the last decade, noroviruses have gained media attention as the cause of large scale outbreaks of gastroenteritis on cruise ships, dormitories, nursing homes, etc. Although noroviruses do not multiply in food or water, they can cause large outbreaks because approximately 10-100 virions are sufficient to cause illness in a healthy adult. Recently, it was shown that the activity of acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) enzyme may be important in norovirus infection. In search of anti-noroviral agents based on the inhibition of ACAT1, we synthesized and evaluated the inhibitory activities of a class of pyranobenzopyrone molecules containing amino, pyridine, substituted quinolines, or 7,8-benzoquinoline nucleus. Three of the sixteen evaluated compounds possess ED(50) values in the low micrometer range. 2-Quinolylmethyl derivative 3A and 4-quinolylmethyl derivative 4A showed ED(50) values of 3.4 and 2.4 µM and TD(50) values of >200 and 96.4 µM, respectively. The identified active compounds are suitable for further modification for the development of anti-norovirus agents.