Unraveling the versatility of human serum albumin - A comprehensive review of its biological significance and therapeutic potential.

Human serum albumin (HSA) is a multi-domain macromolecule with diverse ligand binding capability because of its ability to allow allosteric modulation despite being a monomeric protein. Physiologically, HSA act as the primary carrier for various exogenous and endogenous compounds and fatty acids, and alter the pharmacokinetic properties of several drugs. It has antioxidant properties and is utilized therapeutically to improve the drug delivery of pharmacological agents for the treatment of several disorders. The flexibility of albumin in holding various types of drugs coupled with a variety of modifications makes this protein a versatile drug carrier with incalculable potential in therapeutics. This review provides a brief outline of the different structural properties of HSA, and its various binding sites, moreover, an overview of the genetic, biomedical, and allosteric modulation of drugs and drug delivery aspects of HSA is also included, which may be helpful in guiding advanced clinical applications and further research on the therapeutic potential of this extraordinary protein.

Traced on the Timeline: Discovery of Acetylcholine and the Components of the Human Cholinergic System in a Primitive Unicellular Eukaryote Acanthamoeba spp.

Acetylcholine (ACh) is the neurotransmitter of cholinergic signal transduction that affects the target cells via muscarinic (mAChR) and nicotinic (nAChR) cholinergic receptors embedded in the cell membrane. Of the cholinergic receptors that bind to ACh, the mAChRs execute several cognitive and metabolic functions in the human central nervous system (CNS). Very little is known about the origins and autocrine/paracrine roles of the ACh in primitive life forms. With the recent report of the evidence of an ACh binding mAChR1 like receptor in Acanthamoeba spp., it was tempting to investigate the origin and functional roles of cholinergic G-Protein coupled receptors (GPCRs) in the biology of eukaryotes. We inferred the presence of ACh, its synthetic, degradation system, and a signal transduction pathway in an approximately ∼2.0 billion year old primitive eukaryotic cell Acanthamoeba castellanii. Bioinformatics analysis, ligand binding prediction, and docking methods were used to establish the origins of enzymes involved in the synthesis and degradation of ACh. Notably, we provide evidence of the presence of ACh in A. castellanii by colorimetric analysis, which to date is the only report of its presence in this primitive unicellular eukaryote. We show the evidence for the presence of homology of evolutionary conserved key enzymes of the cholinergic system like choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) in A. castellanii spp., which were found to be near identical to their human counterparts. Tracing the origin, functions of ACh, and primeval mAChRs in primitive eukaryotic cells has the potential of uncovering covert cholinergic pathways that can be extended to humans in order to understand the states of cholinergic deficiency in neurodegenerative diseases (ND).

Antibiotic Effects of Loperamide: Homology of Human Targets of Loperamide with Targets in Acanthamoeba spp.

BACKGROUND: Loperamide is an anti-diarrheal drug prescribed for non-infectious diarrhea. The drug is an opioid receptor agonist, blocker of voltage-dependent calcium channel (Cav) and calmodulin (CaM) inhibitor on human cells. Loperamide has been reported to exert anti-amoebic effects against pathogenic strains of Acanthamoeba castellanii. OBJECTIVES: The precise mode of antibiotic action, cellular target homology with human counterparts and the pattern of cell death induced by loperamide in Acanthamoeba castellanii remain to be established. Additionally, we attempt to establish the presence a primitive Cav in Acanthamoeba castellanii. METHODS: Bioinformatics, 3D structural modelling, ligand binding predictions and apoptotic/ amoebicidal assays were used in this study to answer the above queries. Amino acid sequences and structural models were compared between human and A. castellanii proteins that are involved in the regulation of calcium (Ca+2) homeostasis. RESULTS: Our results show that A. castellanii expresses similar, to near identical types of primitive calcium channels Cav Ac and CaM that are well known targets of loperamide in humans. The growth assays showed anti-amoebic effects of loperamide at different doses, both alone and in combinations with other Ca+2- CaM inhibitors. The synergistic actions of loperamide with haloperidol showed to be more amoebicidal than when either of them used alone. Imaging with Annexin V, Acridine orange and Propidium iodide showed apoptosis in A. castellanii at a dose of 100 µg/ml and necrosis at higher doses of 250 µg/ml. CONCLUSION: Though, Acanthamoeba does not express a homolog of the human mu-opioid receptor, but does shows evidence of the homologs for other known human targets of loperamide that are involved in Ca+2 uptake and Ca+2 signal transduction pathways. This suggests optimization of similar drug interactions with these targets may be useful in developing new approaches to control the growth of this parasite and possibly the diseases caused by it.

Repeated administration of almonds increases brain acetylcholine levels and enhances memory function in healthy rats while attenuates memory deficits in animal model of amnesia.

Dietary nutrients may play a vital role in protecting the brain from age-related memory dysfunction and neurodegenerative diseases. Tree nuts including almonds have shown potential to combat age-associated brain dysfunction. These nuts are an important source of essential nutrients, such as tocopherol, folate, mono- and poly-unsaturated fatty acids, and polyphenols. These components have shown promise as possible dietary supplements to prevent or delay the onset of age-associated cognitive dysfunction. This study investigated possible protective potential of almond against scopolamine induced amnesia in rats. The present study also investigated a role of acetylcholine in almond induced memory enhancement. Rats in test group were orally administrated with almond suspension (400 mg/kg/day) for four weeks. Both control and almond-treated rats were then divided into saline and scopolamine injected groups. Rats in the scopolamine group were injected with scopolamine (0.5 mg/kg) five minutes before the start of each memory test. Memory was assessed by elevated plus maze (EPM), Morris water maze (MWM) and novel object recognition (NOR) task. Cholinergic function was determined in terms of hippocampal and frontal cortical acetylcholine content and acetylcholinesterase activity. Results of the present study suggest that almond administration for 28 days significantly improved memory retention. This memory enhancing effect of almond was also observed in scopolamine induced amnesia model. Present study also suggests a role of acetylcholine in the attenuation of scopolamine induced amnesia by almond.