Microfluidics produced ATRA-loaded PLGA NPs reduced tuberculosis burden in alveolar epithelial cells and enabled high delivered dose under simulated human breathing pattern in 3D printed head models

Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), is second only to COVID-19 as the top infectious disease killer worldwide. Multi-drug resistant TB (MDR-TB) may arise because of poor patient adherence to medications due to lengthy treatment duration and side effects. Delivering novel host directed therapies (HDT), like all trans retinoic acid (ATRA) may help to improve drug regimens and reduce the incidence of MDR-TB. Local delivery of ATRA to the site of infection leads to higher bioavailability and reduced systemic side effects. ATRA is poorly soluble in water and has a short half-life in plasma. Therefore, it requires a formulation step before it can be administered in vivo. ATRA loaded PLGA nanoparticles suitable for nebulization were manufactured and optimized using a scalable nanomanufacturing microfluidics (MF) mixing approach (MF-ATRA-PLGA NPs). MF-ATRA-PLGA NPs demonstrated a dose dependent inhibition of Mtb growth in TB-infected A549 alveolar epithelial cell model while preserving cell viability. The MF-ATRA-PLGA NPs were nebulized with the Aerogen Solo vibrating mesh nebulizer, with aerosol droplet size characterized using laser diffraction and the estimated delivered dose was determined. The volume median diameter (VMD) of the MF-ATRA-PLGA NPs was 3.00 ± 0.18 μm. The inhaled dose delivered in adult and paediatric 3D printed head models under a simulated normal adult and paediatric breathing pattern was found to be 47.05 ± 3 % and 20.15 ± 3.46 % respectively. These aerosol characteristics of MF-ATRA-PLGA NPs supports its suitability for delivery to the lungs via inhalation. The data generated on the efficacy of an inhalable, scalable and regulatory friendly ATRA-PLGA NPs formulation provides a foundation on which further pre-clinical testing can be built. Overall, the results of this project are promising for future research into ATRA loaded NPs formulations as inhaled host directed therapies for TB.

Retinoic acid signaling pathway perturbation impacts mesodermal-tissue development in the zebrafish embryo: Biomarker candidate identification using transcriptomics

The zebrafish embryo (ZE) model provides a developmental model well conserved throughout vertebrate embryogenesis, with relevance for early human embryo development. It was employed to search for gene expression biomarkers of compound-induced disruption of mesodermal development. We were particularly interested in the expression of genes related to the retinoic acid signaling pathway (RA-SP), as a major morphogenetic regulating mechanism. We exposed ZE to teratogenic concentrations of valproic acid (VPA) and all-trans retinoic acid (ATRA), using folic acid (FA) as a non-teratogenic control compound shortly after fertilization for 4 h, and performed gene expression analysis by RNA sequencing. We identified 248 genes specifically regulated by both teratogens but not by FA. Further analysis of this gene set revealed 54 GO-terms related to the development of mesodermal tissues, distributed along the paraxial, intermediate, and lateral plate sections of the mesoderm. Gene expression regulation was specific to tissues and was observed for somites, striated muscle, bone, kidney, circulatory system, and blood. Stitch analysis revealed 47 regulated genes related to the RA-SP, which were differentially expressed in the various mesodermal tissues. These genes provide potential molecular biomarkers of mesodermal tissue and organ (mal)formation in the early vertebrate embryo.

A New Prospect for the Treatment of Nephrotic Syndrome Based on Network Pharmacology Analysis

Network pharmacology is an emerging field which is currently capturing interest in drug discovery and development. Chronic kidney conditions have become a threat globally due to its associated lifelong therapies. Nephrotic syndrome (NS) is a common glomerular disease that is seen in paediatric and adult population with characteristic manifestation of proteinuria, oedema, hypoalbuminemia, and hyperlipidemia. It involves podocyte damage with tubulointerstitial fibrosis and glomerulosclerosis. Till date there has been no specific treatment available for this condition that provides complete remission. Repurposing of drugs can thus be a potential strategy for the treatment of NS. Recently, epigenetic mechanisms were identified that promote progression of many renal diseases. Therefore, in the present study, we investigated two epigenetic drugs valproic acid (VPA) and all-trans retinoic acid (ATRA). Epigenetic drugs act by binging about changes in gene expression without altering the DNA sequence. The changes include DNA methylation or histone modifications. The targets for the two drugs ATRA and VPA were collated from ChEMBL and Binding DB. All the genes associated with NS were collected from DisGeNET and KEGG database. Interacting proteins for the target genes were acquired from STRING database. The genes were then subjected to gene ontology and pathway enrichment analysis using a functional enrichment software tool. A drug-target and drug-potential target-protein interaction network was constructed using the Cytoscape software. Our results revealed that the two drugs VPA and ATRA had 65 common targets that contributed to kidney diseases. Out of which, 25 targets were specifically NS associated. Further, our work exhibited that ATRA and VPA were synergistically involved in pathways of inflammation, renal fibrosis, glomerulosclerosis and possibly mitochondrial biogenesis and endoplasmic reticulum stress. We thus propose a synergistic potential of the two drugs for treating chronic kidney diseases, specifically NS. The outcomes will undoubtedly invigorate further preclinical and clinical explorative studies. We identify network pharmacology as an initial inherent approach in identifying drug candidates for repurposing and synergism.

A practical strategy to subcutaneous administered in-situ gelling co-delivery system of arsenic and retinoic acid for the treatment of acute promyelocytic leukemia

Arsenic trioxide (ATO) combined with all trans retinoic acid (ATRA) is the first choice for the treatment of low and medium risk acute promyelocytic leukemia (APL). Clinical studies reported that the combination of ATO and ATRA could achieve a significant curative effect. However, the retinoic acid syndrome, serious drug resistance and the short half-life in vivo which lead to frequent and large dose administration limit the application of ATRA. In addition, the preparations of arsenic are conventional injections and tablets in clinic, which has poor patients' compliance caused by frequent long-term administration and serious side effects. In order to overcome the above limitations, a phospholipid phase separation gel (PPSG) loaded with ATO and ATRA was developed. ATO+ATRA-PPSG (AAP), as a biodegradable sustained-release delivery system, was the first achievement of co-delivery of hydrophilic ATO and lipophilic ATRA with high drug loading which is the main problem in the application of nano preparation. The prepared PPSG displayed high safety and biocompatibility. The drug in PPSG was released slowly and continuously in vivo and in vitro for up to 10 d, which could reduce the side effects caused by the fluctuation of blood drug concentration and solve the problem of the long treatment cycle and frequent administration. In vivo pharmacokinetics depicted that PPSG could improve the bioavailability, decrease the peak concentration, and prolong the t1/2 of ATO and ATRA. Particularly, AAP significantly inhibited the tumor volume, extended the survival period of tumor-bearing mice, and promoted the differentiation of APL cells into normal cells. Therefore, ATO+ATRA-PPSG not only could co-load hydrophilic ATO and lipophilic ATRA according to the clinical dosage, but also possessed the sustained-release and long-acting treatment effect which was expected to reduce administration time and ameliorate compliance of patients. Thus, it had great potential for clinical transformation and application.

Oral encapsulated transforming growth factor β1 reduces endogenous levels: Effect on inflammatory bowel disease

BACKGROUND

TreXTAM^® is a combination of the key regulatory cytokine transforming growth factor beta (TGFβ) and all trans retinoic acid (ATRA) microencapsulated for oral delivery to immune structures of the gut. It is in development as a novel treatment for inflammatory bowel disease (IBD).

AIM

To measure TGFβ levels in blood and tissue after oral administration of encapsulated TGFβ.

METHODS

Animals were orally administered encapsulated TGFβ by gavage. Levels of drug substance in blood and in gut tissues at various times after administration were measured by ELISA.

RESULTS

We made the surprising discovery that oral administration of TreXTAM dramatically (approximately 50%) and significantly (P = 0.025) reduced TGFβ levels in colon, but not small intestine or mesenteric lymph nodes. Similarly, levels in rat serum after 25 d of thrice weekly dosing with either TreXTAM, or microencapsulated TGFβ alone (denoted as TPX6001) were significantly (P < 0.01) reduced from baseline levels. When tested in the SCID mouse CD4+CD25- adoptive cell transfer (ACT) model of IBD, oral TPX6001 alone provided only a transient benefit in terms of reduced weight loss.

CONCLUSION

These observations suggest a negative feedback mechanism in the gut whereby local delivery of TGFβ results in reduced local and systemic levels of the active form of TGFβ. Our findings suggest potential clinical implications for use of encapsulated TGFβ, perhaps in the context of IBD and/or other instances of fibrosis and/or pathological TGFβ signaling.

Retinoic acid decreases the severity of Salmonella enterica serovar Typhimurium mediated gastroenteritis in a mouse model

Gastroenteritis is a global burden; it's the major cause of morbidity and mortality both in adults and children of developing countries. Salmonella is one of the leading causes of bacteria-mediated gastroenteritis and due to its increasing multidrug antibiotic resistance; Salmonella-mediated gastroenteritis is difficult to control. Retinoic acid, the biologically active agent of vitamin A has an anti-inflammatory effect on experimental colitis. In this study we have shown All trans retinoic acid (ATRA) treatment down regulates Salmonella-mediated colitis in a murine model. Macroscopic signs of inflammation such as decrease in body weight and cecum weight, shorter length of proximal colon and pathological score of colitis were observed less in ATRA treated mice than in a vehicle control group. ATRA treatment not only reduced pro-inflammatory cytokine responses, such as TNF-α, IL-6, IL-1β, IFN-γ and IL-17 production but also increased IL-10 response in the supernatant of intestinal tissue. Results also suggested that ATRA treatment enhances the number of FoxP3-expressing T regulatory cells in MLN and also decreases bacterial load in systemic organs. We concluded that ATRA treatment indeed reduces Salmonella Typhimurium-mediated gastroenteritis in mice, suggesting it could be an important part of an alternative therapeutic approach to combat the disease.

All trans retinoic acid (ATRA) mediated modulation of N-methyl D-aspartate receptor (NMDAR) and Kruppel like factor 11 (KLF11) expressions in the mitigation of ethanol induced alterations in the brain

BACKGROUND

Damaging effects that chronic ethanol exposure causes to the brain and the neurons are well documented. Ethanol and its toxic metabolites increase the oxidative stress in brain. Chronic exposure to ethanol leads to upregulation of N-methyl D-aspartate receptors (NMDAR) and also activates Kruppel like factor 11 (KLF11) mediated death cascade and thereby neurodegeneration.

OBJECTIVE

Ethanol depletes vitamin A stores. But supplementation of vitamin A exacerbates ethanol induced toxicity since alcohol and its metabolites are competitive inhibitors of the enzymes involved in the metabolism of vitamin A. Hence, in this study we investigated the impact of co-administration of ethanol and all trans retinoic acid (ATRA), active metabolite of vitamin A, on ethanol induced alterations to the brain.

MATERIALS AND METHODS

Male Sprague Dawley rats, adolescent, were grouped as follows and maintained for 90 days. I - Control, II - Ethanol (4 g/kg b.w.), III - ATRA (100 µg/kg b.w.), IV - Ethanol (4 g/kg b.w.), +ATRA (100 µg/kg b.w.). Oxidative stress and the mRNA expression of various receptors for the neurotransmitter involved in glutamergic, serotonergic and gabaergic pathways were studied in the brain homogenate.

RESULTS

Ethanol treatment was shown to decrease brain weight and it was increased on ATRA treatment. Increase in oxidative stress due to ethanol treatment was also brought down on ATRA administration. Ethanol induced upregulation of NMDAR and KLF11 was also downregulated on ATRA supplementation. The alterations in the levels of neurotransmitters and the expression of their receptors due to ethanol treatment also were ameliorated on ATRA supplementation.

CONCLUSION

Our results show that ATRA supplementation mitigates the ethanol induced alterations in the brain by reducing oxidative stress in the brain with concurrent suppression of NMDAR and KLF11 expression leading to enhanced catabolism of neurotransmitters.