Search Results (84)

Short- and medium-sized peptides have long been used as effective and versatile organocatalysts. In the early 80s, Inoue used diketopiperazines in the Strecker reaction, while Juliá and Colonna reported the epoxidation of chalcone catalyzed by poly-L-Ala. Since then, a variety of peptide-catalyzed reactions have been described. However, peptide synthesis typically implicates the use of toxic reagents and generates wastes; therefore, peptide recycling is expected to significantly improve the overall sustainability of the process. Easy recovery and recycling of peptide catalysts can be expediently attained by covalent binding, inclusion, or adsorption. In addition, immobilization can significantly accelerate the screening of new peptide catalysts. For these reasons, diverse supports have been tested, including natural or synthetic polymers, porous polymeric networks, inorganic porous materials, organic-inorganic hybrid materials, and finally metal–organic frame-works. Full article

Neurological disorders, encompassing neurodegenerative and neuroinflammatory conditions, present significant public health and clinical challenges. Recent research has elucidated the pivotal role of various enzymes in the onset and progression of these disorders. This review explores the therapeutic potential of targeting these enzymes with natural and synthetic molecules. Key enzymes, including acetylcholinesterase, monoamine oxidase, beta-secretase, tau kinases, caspases, and cyclooxygenase-2, are implicated in diseases such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Modulating these enzymes can alleviate symptoms, slow disease progression, or reverse pathological changes. Natural molecules derived from plants, microbes, seaweeds, and animals have long been noted for their therapeutic potential. Their ability to interact with specific enzymes with high specificity and minimal side effects makes them promising candidates for treatment. These natural agents provide a foundation for developing targeted therapies with improved safety profiles. Simultaneously, the development of synthetic chemistry has resulted in molecules designed to inhibit neurodegenerative enzymes with precision. This review examines the progress in creating small molecules, peptides, and enzyme inhibitors through sophisticated drug design techniques. It evaluates the efficacy, safety, and mechanisms of these synthetic agents, highlighting their potential for clinical application. The review offers a comprehensive overview of recent advancements in enzyme-targeted therapies for neurological disorders, covering both natural and synthetic molecules investigated in preclinical and clinical settings. It discusses the mechanisms through which these molecules exert their effects, the challenges faced in their development, and future research directions. By synthesizing current knowledge, this paper aims to illuminate the potential of enzyme-targeted interventions in managing neurological disorders, showcasing both the promise and limitations of these approaches. Full article

Recent epidemiological studies have indicated that exposure to particulate matter with an aerodynamic diameter of 2.5 μm or less in the ambient air (PM_2.5) is significantly associated with an elevated risk of developing Alzheimer’s disease (AD) and its progression. Scorpion venom heat-resistant synthetic peptide (SVHRSP) exhibits anti-inflammatory and neuroprotective properties. However, the exact ways in which SVHRSP mitigates the progression of AD induced by PM_2.5 are still unknown. Long non-coding RNA (lncRNA) plays a crucial role in various biological processes. Necroptosis, a form of programmed cell death, has garnered considerable attention in recent years. This study aims to investigate whether Lnc Gm16410 and neuronal necroptosis are involved in PM_2.5-exacerbated AD progression and the mechanisms of SVHRSP in alleviating this process. Through the establishment of a PM_2.5 exposure model in AD mice and an in vitro model, it was found that PM_2.5 exposure could promote necroptosis and the down-regulation of Lnc Gm16410, thereby promoting the progression of AD. Behavioral tests showed that SVHRSP alleviated cognitive impairment in PM_2.5-induced AD mice. WB, qRT-PCR, and other molecular biological assays indicate that Lnc Gm16410 regulates neuronal necroptosis under PM_2.5 exposure via the p38 MAPK pathway. SVHRSP is a potential regulator of AD progression by regulating Lnc Gm16410 to alleviate PM_2.5 exposure-induced necroptosis. These findings offer new insights into the mechanism through which PM_2.5 exposure accelerates the progression of AD, examined from the perspective of LncRNA. Furthermore, we offer new targets for the treatment and prevention of AD following PM_2.5 exposure by investigating the mechanism of action of SVHRSP in alleviating AD. Full article

Background: A previous phase I/II study demonstrated potent and long-term immune responses in men with prostate cancer following vaccination with a 20mer synthetic peptide (RV001) derived from the Ras homolog gene family member C protein (RhoC). Moreover, a fraction of patients experienced prostate-specific antigen (PSA) responses, which prompted the initiation of a phase II double-blind randomized trial (NCT04114825). The primary endpoint was to study whether vaccination could postpone PSA progression. Furthermore, the study included an evaluation of vaccination-induced immune responses, and in-depth in vitro studies of RhoC-specific CD4⁺ T cell responses. Methods: Men with non-metastatic biochemical recurrence after either radical prostatectomy or radiation therapy were eligible for the study. Participants were randomized 1:1 to either subcutaneous injections of 0.1 mg/mL RV001 emulsified in Montanide ISA 51, or a placebo. Vaccinations were administered every 2 weeks for the first six times, then five times every 4 weeks for a total treatment time of 30 weeks. Blood samples were collected from a subset of patients (n = 38) over the course of vaccination, and peripheral blood mononuclear cells (PBMCs) isolated for immunological assessment of vaccine-induced immune responses. Experiments using PBMCs from a healthy donor and a patient were performed to study the phenotype and function of RV001-specific CD4⁺ T cells. Results: A total of 192 men entered the study. There was no difference in time to PSA doubling, with 7.5 versus 9.3 months, or in time to initiating further therapies, 11.2 versus 17.6 months for treatment and control groups, respectively. At long-term follow-up, 12.9% of the patients in the vaccination arm had developed metastasis compared to 12% in the placebo arm. No serious treatment-related side effects were observed, and treatment-related adverse events did not differ between groups. Immunological examinations in a subset of patients demonstrated that the vaccination induced potent, long-lasting CD4⁺ T cell responses capable of proliferation and cytokine production. RV001-specific CD4⁺ T cells were shown to mediate cytotoxicity against a RhoC-expressing cancer cell line in an HLA-class II-dependent manner. Conclusions: Men randomized to active treatment with RV001V demonstrated the induction of potent, functionally capable, anti RhoC-CD4⁺ T cell responses. However, there was no benefit in time to biochemical progression, and no difference in time to the initiation of second-line therapies. Full article

Functionally important amino acid sequences in proteins are often located at multiple sites. Three-dimensional structural analysis and site-directed mutagenesis may be performed to allocate functional sites for understanding structure‒function relationships and for developing novel inhibitory drugs. However, such methods are too demanding to comprehensively cover potential functional sites throughout a protein chain. Here, a peptide inhibitor assay (PIA) was devised to allocate functionally important accessible sites in proteins. This simple method presumes that protein‒ligand interactions, intramolecular interactions, and dimerization interactions can be partially inhibited by high concentrations of competitive “endogenous” peptides of the protein of interest. Focusing on the restriction endonuclease EcoRI as a model protein system, many endogenous peptides (6mer-14mer) were synthesized, covering the entire EcoRI protein chain. Some of them were highly inhibitory, but interestingly, the nine most effective peptides were located outside the active sites, with the exception of one. Relatively long peptides with aromatic residues (F, H, W, and Y) corresponding to secondary structures were generally effective. Because synthetic peptides are flexible enough to change length and amino acid residues, this method may be useful for quickly and comprehensively understanding structure‒function relationships and developing novel drugs or epitopes for neutralizing antibodies. Full article

Gut peptides, including glucagon-like peptide-1 (GLP-1), regulate metabolic homeostasis and have emerged as the basis for multiple state-of-the-art diabetes and obesity therapies. We previously showed that G protein-coupled receptor 17 (GPR17) is expressed in intestinal enteroendocrine cells (EECs) and modulates nutrient-induced GLP-1 secretion. However, the GPR17-mediated molecular signaling pathways in EECs have yet to be fully deciphered. Here, we expressed the human GPR17 long isoform (hGPR17L) in GLUTag cells, a murine EEC line, and we used the GPR17 synthetic agonist MDL29,951 together with pharmacological probes and genetic approaches to quantitatively assess the contribution of GPR17 signaling to GLP-1 secretion. Constitutive hGPR17L activity inhibited GLP-1 secretion, and MDL29,951 treatment further inhibited this secretion, which was attenuated by treatment with the GPR17 antagonist HAMI3379. MDL29,951 promoted both Gi/o and Gq protein coupling to mediate cyclic AMP (cAMP) and calcium signaling. hGPR17L regulation of GLP-1 secretion appeared to be Gq-independent and dependent upon Gi/o signaling, but was not correlated with MDL29,951-induced whole-cell cAMP signaling. Our studies revealed key signaling mechanisms underlying the role of GPR17 in regulating GLP-1 secretion and suggest future opportunities for pharmacologically targeting GPR17 with inverse agonists to maximize GLP-1 secretion. Full article

Recent clinical trials using synthetic incretin hormones, glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) receptor agonists have demonstrated that these treatments ameliorated many complications related to obesity, emphasizing the significant impact of body weight on overall health. Incretins are enteroendocrine hormones secreted by gut endothelial cells triggered by nutrient ingestion. The phenomenon that oral ingestion of glucose elicits a much higher insulin secretion than intra-venous injection of equimolar glucose is known as the incretin effect. This also alludes to the thesis that food intake is the root cause of insulin resistance. Synthetic GLP-1 and GIP agonists have demonstrated unprecedented glucoregulation and body weight reduction. Also, randomized trials have shown their ability to prevent complications of obesity, including development of diabetes from prediabetes, reducing cardiovascular disease risks and renal complications in diabetic patients. Moreover, the benefits of these agonists persist among the patients who are already on metformin or insulin. The ultimate question is “Are these benefits of incretin agonism sustainable?” Chronic agonism of pancreatic β-cells may decrease the number of receptors and cause β-cell exhaustion, leading to β-cell failure. Unfortunately, the long-term effects of these drugs are unknown at the present because the longest duration in randomized trials is 3 years. Additionally, manipulation of the neurohormonal axis to control satiety and food intake may hinder the long-term sustainability of these treatments. In this review, we will discuss the incretins’ mechanism of action, challenges, and future directions. We will briefly review other molecules involved in glucose homeostasis such as amylin and glucagon. Amylin is co-expressed with insulin from the pancreas β-cells but does not have insulinotropic function. Amylin suppresses glucagon secretion, slowing gastric emptying and suppressing the reward center in the central nervous system, leading to weight loss. However, amylin can self-aggregate and cause serious cytotoxicity and may cause β-cell apoptosis. Glucagon is secreted by pancreatic α-cells and participates in glucose homeostasis in a glucose-dependent manner. In hypoglycemia, glucagon increases the blood glucose level by glycogenolysis and gluconeogenesis and inhibits glycogenesis in the liver. Several triple agonists, in combination with dual incretins and glucagon, are being developed. Full article

Background: Glucagon-like peptide-1 receptor agonists (GLP1-RAs) are synthetic peptides that mimic the natural activity of GLP-1, widely known for lowering blood glucose levels and promoting weight reduction. These characteristics make them a valuable tool in managing type 2 diabetes and obesity-related conditions. Recent findings indicate that GLP1-RAs may also offer therapeutic benefits in managing hidradenitis suppurativa (HS), a chronic inflammatory skin disorder closely associated with metabolic abnormalities, including obesity, diabetes, and dyslipidemia. This review explores the potential role of GLP1-RAs in managing HS. Methods: A systematic review was conducted by searching electronic databases, including MEDLINE and Google Scholar, without date limitations. Key search terms included “GLP-1” or “GLP-1 agonists” combined with “hidradenitis suppurativa” or “acne inversa”. Inclusion criteria were set for studies reporting on the use of GLP1-RAs as a treatment for HS, with articles discussing theoretical applications excluded. Data synthesis included findings from 25 relevant studies. Results: The analysis revealed that GLP1-RAs, specifically liraglutide and semaglutide, led to significant reductions in weight and systemic inflammation in HS patients. Notably, improvements in lesion severity and quality of life were reported. The anti-inflammatory effects of GLP1-RAs were attributed to the suppression of key inflammatory pathways involving TNF-α, IL-17, and NF-κB. Conclusions: GLP1-RAs demonstrate significant potential as an adjunct therapy for HS, addressing both the metabolic and inflammatory aspects of the condition. While early results are promising, further research is necessary to determine their long-term efficacy in managing HS. Full article

Using free microorganisms for industrial processes has some limitations, such as the extensive consumption of substrates for growth, significant sensitivity to the microenvironment, and the necessity of separation from the product and, therefore, the cyclic process. It is widely acknowledged that confining or immobilizing cells in a matrix or support structure enhances enzyme stability, facilitates recycling, enhances rheological resilience, lowers bioprocess costs, and serves as a fundamental prerequisite for large-scale applications. This report summarizes the various cell immobilization methods, including several synthetic (polyvinylalcohol, polyethylenimine, polyacrylates, and Eudragit) and natural (gelatin, chitosan, alginate, cellulose, agar–agar, carboxymethylcellulose, and other polysaccharides) polymeric materials in the form of thin films, hydrogels, and cryogels. Advancements in the production of well-known antibiotics like penicillin and cephalosporin by various strains were discussed. Additionally, we highlighted cutting-edge research related to strain producers of peptide-based antibiotics (polymyxin B, Subtilin, Tyrothricin, varigomycin, gramicidin S, friulimicin, and bacteriocin), glusoseamines, and polyene derivatives. Crosslinking agents, especially covalent linkers, significantly affect the activity and stability of biocatalysts (penicillin G acylase, penicillinase, deacetoxycephalosporinase, L-asparaginase, β-glucosidase, Xylanase, and urease). The molecular weight of polymers is an important parameter influencing oxygen and nutrient diffusion, the kinetics of hydrogel formation, rigidity, rheology, elastic moduli, and other mechanical properties crucial for long-term utilization. A comparison of stability and enzymatic activity between immobilized enzymes and their free native counterparts was explored. The discussion was not limited to recent advancements in the biopharmaceutical field, such as microorganism or enzyme immobilization, but also extended to methods used in sensor and biosensor applications. In this study, we present data on the advantages of cell and enzyme immobilization over microorganism (bacteria and fungi) suspension states to produce various bioproducts and metabolites—such as antibiotics, enzymes, and precursors—and determine the efficiency of immobilization processes and the optimal conditions and process parameters to maximize the yield of the target products. Full article

The cell wall is an indispensable element of bacterial cells and a long-known target of many antibiotics. Penicillin, the first discovered beta-lactam antibiotic inhibiting the synthesis of cell walls, was successfully used to cure many bacterial infections. Unfortunately, pathogens eventually developed resistance to it. This started an arms race, and while novel beta-lactams, either natural or (semi)synthetic, were discovered, soon upon their application, bacteria were developing resistance. Currently, we are facing the threat of losing the race since more and more multidrug-resistant (MDR) pathogens are emerging. Therefore, there is an urgent need for developing novel approaches to combat MDR bacteria. The cell wall is a reasonable candidate for a target as it differentiates not only bacterial and human cells but also has a specific composition unique to various groups of bacteria. This ensures the safety and specificity of novel antibacterial agents that target this structure. Due to the shortage of low-molecular-weight candidates for novel antibiotics, attention was focused on peptides and proteins that possess antibacterial activity. Here, we describe proteinaceous agents of various origins that target bacterial cell wall, including bacteriocins and phage and bacterial lysins, as alternatives to classic antibiotic candidates for antimicrobial drugs. Moreover, advancements in protein chemistry and engineering currently allow for the production of stable, specific, and effective drugs. Finally, we introduce the concept of selective targeting of dangerous pathogens, exemplified by staphylococci, by agents specifically disrupting their cell walls. Full article

Protein cysteine S-glycosylation is a relatively rare and less well characterized post-translational modification (PTM). Creating reliable model proteins that carry this modification is challenging. The lack of available models or natural S-glycosylated proteins significantly hampers the development of mass-spectrometry-based (MS-based) methodologies for detecting protein cysteine S-glycosylation in real-world proteomic studies. There is also limited MS-sequencing data describing it as easier to create synthetic S-glycopeptides. Here, we present the results of an in-depth manual analysis of automatically annotated CID/HCD spectra for model S-glucopeptides. The CID spectra show a long series of y/b-fragment ions with retained S-glucosylation, regardless of the dominant m/z signals corresponding to neutral loss of 1,2-anhydroglucose from the precursor ions. In addition, the spectra show signals manifesting glucosyl transfer from the cysteine position onto lysine, arginine (Lys, Arg) side chains, and a peptide N-terminus. Other spectral evidence indicates that the N-glucosylated initial products of transfer are converted into N-fructosylated (i.e., glycated) structures due to Amadori rearrangement. We discuss the peculiar transfer of the glucose oxocarbenium ion (Glc+) to positively charged guanidinium residue (ArgH+) and propose a mechanism for the gas-phase Amadori rearrangement involving a 1,2-hydride ion shift. Full article

The COVID-19 pandemic has been one of the most impactful events in our lifetime, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Multiple SARS-CoV-2 variants were reported globally, and a wide range of symptoms existed. Individuals who contract COVID-19 continue to suffer for a long time, known as long COVID or post-acute sequelae of COVID-19 (PASC). While COVID-19 vaccines were widely deployed, both unvaccinated and vaccinated individuals experienced long-term complications. To date, there are no treatments to eradicate long COVID. We recently conceived a new approach to treat COVID in which a 15-amino-acid synthetic peptide (SPIKENET, SPK) is targeted to the ACE2 receptor binding domain of SARS-CoV-2, which prevents the virus from attaching to the host. We also found that SPK precludes the binding of spike glycoproteins with the receptor carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) of a coronavirus, murine hepatitis virus-1 (MHV-1), and with all SARS-CoV-2 variants. Further, SPK reversed the development of severe inflammation, oxidative stress, tissue edema, and animal death post-MHV-1 infection in mice. SPK also protects against multiple organ damage in acute and long-term post-MHV-1 infection. Our findings collectively suggest a potential therapeutic benefit of SPK for treating COVID-19. Full article

We identified a new human voltage-gated potassium channel blocker, NnK-1, in the jellyfish Nemopilema nomurai based on its genomic information. The gene sequence encoding NnK-1 contains 5408 base pairs, with five introns and six exons. The coding sequence of the NnK-1 precursor is 894 nucleotides long and encodes 297 amino acids containing five presumptive ShK-like peptides. An electrophysiological assay demonstrated that the fifth peptide, NnK-1, which was chemically synthesized, is an effective blocker of hKv1.3, hKv1.4, and hKv1.5. Multiple-sequence alignment with cnidarian Shk-like peptides, which have Kv1.3-blocking activity, revealed that three residues (³Asp, ²⁵Lys, and ³⁴Thr) of NnK-1, together with six cysteine residues, were conserved. Therefore, we hypothesized that these three residues are crucial for the binding of the toxin to voltage-gated potassium channels. This notion was confirmed by an electrophysiological assay with a synthetic peptide (NnK-1 mu) where these three peptides were substituted with ³Glu, ²⁵Arg, and ³⁴Met. In conclusion, we successfully identified and characterized a new voltage-gated potassium channel blocker in jellyfish that interacts with three different voltage-gated potassium channels. A peptide that interacts with multiple voltage-gated potassium channels has many therapeutic applications in various physiological and pathophysiological contexts. Full article

Cancer vaccines have emerged as a potent strategy to improve cancer immunity, with or without the combination of checkpoint blockade. In our investigation, liposomal formulations containing synthetic long peptides and α-Galactosylceramide, along with a DC-SIGN-targeting ligand, Lewis Y (Le^Y), were studied for their anti-tumor potential. The formulated liposomes boosted with anti-CD40 adjuvant demonstrated robust invariant natural killer (iNKT), CD4⁺, and CD8⁺ T-cell activation in vivo. The incorporation of Le^Y facilitated the targeting of antigen-presenting cells expressing DC-SIGN in vitro and in vivo. Surprisingly, mice vaccinated with Le^Y-modified liposomes exhibited comparable tumor reduction and survival rates to those treated with untargeted counterparts despite a decrease in antigen-specific CD8⁺ T-cell responses. These results suggest that impaired induction of antigen-specific CD8⁺ T-cells via DC-SIGN targeting does not compromise anti-tumor potential, hinting at alternative immune activation routes beyond CD8⁺ T-cell activation. Full article

Generally, lncPEPs (peptides encoded by long non-coding RNAs) have been identified in many plant species of several families and in some animal species. Importantly, molecular mechanisms of the miPEPs (peptides encoded by primary microRNAs, pri-miRNAs) are often poorly understood in different flowering plants. Requirement for the additional studies in these directions is highlighted by alternative findings concerning positive regulation of pri-miRNA/miRNA expression by synthetic miPEPs in plants. Further extensive studies are also needed to understand the full set of their roles in eukaryotic organisms. This review mainly aims to consider the available data on the regulatory functions of the synthetic miPEPs. Studies of chemically synthesized miPEPs and analyzing the fine molecular mechanisms of their functional activities are reviewed. Brief description of the studies to identify lncORFs (open reading frames of long non-coding RNAs) and the encoded protein products is also provided. Full article