Current Protein and Peptide Science - Volume 22, Issue 9, 2021

For many years, natural products have played a crucial role in drug discovery and drug design as a source of active agents or as inspiration. Lactoferrin (Lf), a glycoprotein found in milk and mammalian secretions, has been extensively studied in recent years, and numerous antimicrobial, anti-inflammatory, and anticancer properties of Lf have been demonstrated in the literature. The use of lactoferrin as a co-agent or supplement to enhance the beneficial effect of drugs, or to reduce their side effects, arouses the interest of many researchers, especially since Lf is a well-studied, biocompatible, cheap, and easily accessible protein. In this mini-review, we focus on the elucidation of the role of Lf in antimicrobial or anticancer therapies, pointing to the possible mechanism underlying the determined synergism between Lf and commonly used drugs.

For decades now, neurodegenerative disorders have been explored, but their prompt detection is still very strenuous due to the complexity of the brain. This entails the demand for identification and development of clinical biomarkers in order to comply with the criteria of precision, specificity and repeatability. The use of rapidly evolving technologies such as Mass Spectrometry (MS) in proteomics has opened new ways to speed up the discovery of biomarkers, both for diagnostic and prognostic purposes. The wide range of possibilities for the detection of differentially expressed proteins in specific diseases has been opened by several novel proteomic techniques such as cross-linking mass spectrometry, hydrogen-deuterium exchange mass spectrometry, protein foot printing and more. Still, much research is required to give a deep insight into the complex system of the brain and its related disorders for unraveling prognostic and diagnostic biomarkers, which can be used to either enhance a certain function of our brain or to cure a particular disease/disorder. This review summarizes the latest developments in neuroproteomics and analyzes existing and potential directions for the discovery of biomarkers for neurodegenerative diseases.

Peptides are small molecules composed of amino acids linked together by peptide bonds. The targeted action of these peptides along with their magnificent ability to reach locations in the body that are complicated to access, is being considered of tremendous potential in disease modifying therapies. Synthetic as well as natural peptides like Carnosine are currently under research for the treatment of Neurodegenerative Disorders (NDDs). Peptide based vaccines are currently under immense research for diseases like dementia. Toxicity of peptide-based drugs towards eukaryotic cells due to their increased haemolytic activity is of major concern and this is being tackled by introducing modifications into the peptide structure. Some crucial peptide inhibitors currently in use for neurodegenerative disorders include Aβ (16-20) KLVFF for Alzheimer’s disease, NAPVSIPQ (NAP) for Parkinson’s disease, towards eukaryotic cells Vasoactive Intestinal Peptides (VIP) for Huntington’s disease, Polyglutamine Binding Peptide-1(QBP1) for Dentatorubral- pallidoluysian atrophy (DRPLA). Certain peptides are involved in inhibition of Mitochondrial Permeability Transition (MPT) that plays a prominent part in the materialization of neurodegenerative diseases, one such example of peptides being Ba-V which is obtained from Bothrops atrox snake venom. New therapeutic peptides are being identified using bioinformatics tools like High Throughput Screening (HTS). These tools are being used to explore the selectivity, stability, extent of immune response and toxic side effects of peptides. Apart from neurodegenerative diseases, the potential of bioactive peptides is also being tested against cancer, diabetes and microbes. This review focuses on the recent advances in peptide therapeutics and novel peptides discovered for the treatment of NDs.

The moonlighting protein, Prdx-6, exhibits peroxidase activity, phospholipase activity, and lysophosphatidylcholine acyltransferase (LPCAT) activity. Although it is ubiquitous in expression, its level is prominently high in the lung. Prdx-6 has been known to be an important enzyme for the maintenance of normal lung physiologies including, anti-oxidant defense, lung surfactant homeostasis, and cell signaling. Studies further unveiled that the altered activity (peroxidase or ai- PLA2) of this enzyme is linked with various lung pathologies or diseases. In the present article, we attempted to address the various pathophysiologies or disease conditions (like lung ischemia, hyperoxia, lung cancer, emphysema, and acute lung injury) wherein Prdx-6 is involved. The study implicates that Prdx-6 could be used as a common drug target for multiple lung diseases. Important future insights have also been incorporated.

The approval of istradefylline, an adenosine 2A receptor (A2AR) antagonist, as an addon treatment in adult patients with Parkinson’s disease by the Food and Drug Administration (FDA) and European Medicines Agency (EMA), is the latest proof of the importance of the adenosinergic system in the nervous system. Adenosine is an endogenous purine nucleoside with a role as a modulator of both neurotransmission and the inflammatory response. As such, the expression pattern of the 4 adenosine receptors (A1R, A2AR, A2BR and A3R) and the extracellular adenosine levels have attracted great interest in the pathogenesis and possible treatment of rare neurodegenerative diseases with motor symptoms. These include Huntington’s Disease (HD), Amyotrophic Lateral Sclerosis (ALS), Multiple Sclerosis (MS), Restless Legs Syndrome (RLS) and Machado-Joseph Disease (MJD, also known as spinocerebellar ataxia type 3, SCA3). In this review, we shall focus on the role of the different adenosine receptor subtypes in the development and possible treatment of the aforementioned rare neurodegenerative diseases with motor symptoms using the currently available data. The last section discusses the possibility of a role for the adenosine receptors in the treatment of other rare diseases based on the available molecular pathology knowledge.