Josephine Esposto

Cataract is a leading cause of blindness worldwide, with no clear pharmacological agent for treatment. An octa-sulfonated polyanionic resorcinarene MR-8S was synthesized and investigated for its ability to inhibit the aggregation of αA66-80-Crystallin peptide, a key peptide of the αA-Crystallin protein involved in cataract formation. Nuclear magnetic resonance (NMR) and isothermal titration calorimetry (ITC) experiments revealed strong interactions between MR-8S and the nine amino acids that make up the αA66-80-Crystallin peptide as well as the peptide. ITC revealed dissociation constants ranging between 1 nm and 1000 μM. Fluorescence aggregation assays, dynamic light scattering (DLS) experiments, and transmission electron microscopy (TEM) graphs illustrated a concentration-dependent deaggregation ability of MR-8S toward αA66-80-Crystallin peptide in physiological solutions. At 1:1 equivalence of αA66-80-Crystallin and MR-8S, the average particle size of αA66-80 peptide aggregate dropped almost 9-fold (from 13293 ± 1072 d.nm to 1483 ± 15 d.nm), which was less than that determined for previously reported macrocycles with the same batch of peptide at a similar concentration. Evident from TEM imaging, varying ratios of MR-8S and αA66-80-Crystallin peptide produced fibrillar aggregates of the peptide when compared to pure αA66-80 Crystallin peptide. A concentration of 44 ± 1 μM of MR-8S was needed to break down 50% of αA66-80 peptide aggregates, which was significantly lower than reported IC₅₀ values for two reported functionalized resorcinarenes and doubles that of a third macrocycle. Molecular dynamics (MD) simulations further showed that aggregation of the αA66-80 peptide was driven by core hydrophobic residues, which were effectively shielded by MR-8S, thereby inhibiting the formation of peptide aggregates. Among the four polyionic resorcinarenes tested, MR-8S displayed the strongest deaggregation effects, highlighting its potential as a molecular scaffold for the development of anticataract therapeutics.

Gastric cancer ranks as the fifth-leading contributor to global cancer incidence and the fourth-highest in terms of cancer-related mortality. Helicobacter pylori (H. pylori) infection leads to inflammation and ulceration, atrophic and chronic gastritis, and eventually, increases the risk of developing gastric adenocarcinoma. In this paper, we delve into the combined impact of a high-salt diet (HSD) and concurrent H. pylori infection, which act as predisposing factors for gastric malignancy. A multitude of mechanisms come into play, fostering the development of gastric adenocarcinoma due to the synergy between an HSD and H. pylori colonization. These encompass the disruption of mucosal barriers, cellular integrity, modulation of H. pylori gene expression, oxidative stress induction, and provocation of inflammatory responses. On the whole, gastric cancer patients were reported to have a higher median sodium intake with respect to healthy controls. H. pylori infection constitutes an additional risk factor, with a particular impact on the population with the highest daily sodium intake. Consequently, drawing from epidemiological discoveries, substantial evidence suggests that diminishing salt intake and employing antibacterial therapeutics could potentially lower the susceptibility to gastric cancer among individuals.

Background: TAR DNA‐binding protein 43 (TDP‐43) is a highly conserved nuclear protein, predominantly associated with RNA metabolism. Aberrant TDP‐43 inclusions are present in over 95% of post‐mortem brain tissue samples from Amyotrophic Lateral Sclerosis (ALS) patients. The highly disordered TDP‐43 C‐Terminal Domain (CTD) is associated with the greatest amount of disease‐related mutations and phosphorylation sites. The exact mechanism of TDP‐43 aggregation and formation into a pathological state has yet to be elucidated but is an important therapeutic target to consider.Method: Full‐length phosphorylated TDP‐43 (pS410) protein was treated with 6 hours of daily agitation over 9 days in vitro. Agitation and aging took place with and without the presence of TDP‐43 RRM2‐CTD specific antibodies. Dot‐blot analysis was performed to confirm the binding of antibodies to TDP‐43. Aggregation was monitored and characterized using biophysical analysis; methods included Thioflavin T (ThT), turbidity, and transmission electron microscopy (TEM).Result: Phospho‐TDP‐43 that had undergone agitation and extensive aging formed insoluble aggregates and ThT positive fibrils. The incubation with antibodies specific to the RRM2‐CTD inhibited aggregation and fibril formation in a concentration‐dependent manner.Conclusion: Similar immunotherapies exist for other neurodegenerative disease‐related proteins; inhibition of TDP‐43 aggregation and fibril formation using antibodies demonstrates the potential for the epitope‐specific treatment of TDP‐43 proteinopathies.1) Esposto, J., & Martic‐Milne, S. (2021). Biochimica et Biophysica Acta (BBA) ‐ Molecular Basis of Disease, 1867, https://doi.org/10.1016/j.bbadis.2021.166234.

Aging constitutes progressive physiological changes in an organism. These changes alter the normal biological functions, such as the ability to manage metabolic stress, and eventually lead to cellular senescence. The process itself is characterized by nine hallmarks: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. These hallmarks are risk factors for pathologies, such as cardiovascular diseases, neurodegenerative diseases, and cancer. Emerging evidence has been focused on examining the genetic pathways and biological processes in organisms surrounding these nine hallmarks. From here, the therapeutic approaches can be addressed in hopes of slowing the progression of aging. In this review, data have been collected on the hallmarks and their relative contributions to aging and supplemented with in vitro and in vivo antiaging research experiments. It is the intention of this article to highlight the most important antiaging strategies that researchers have proposed, including preventive measures, systemic therapeutic agents, and invasive procedures, that will promote healthy aging and increase human life expectancy with decreased side effects.

Cataracts, an eye lens clouding disease, are debilitating and while operable, remain without a cure. αA66-80 crystallin peptide abundant in cataracted eye lenses contributes to aggregation of αA-crystallin protein leading to cataracts. Inspired by the versatility of macrocycles and programmable guest selectivity through discrete functionalizations, we report on three water-soluble ionic resorcinarene receptors (A, B, and C) that disrupt the aggregation of αA66-80 crystallin peptide. A and B each possess four anionic sulfonate groups, while C includes four cationic ammonium groups with four flexible extended benzyl groups. Through multiple non-covalent attractions, these receptors successfully disrupt and reverse the aggregation of αA66-80 crystallin peptide, which was studied through spectroscopic, spectrometric, calorimetric, and imaging techniques. The αA66-80·receptor complexes were also explored using molecular dynamics simulation, and binding energies were calculated. Even though each of the three receptors can bind with the peptide, receptor C was characterized by the highest binding energy and affinity for three different domains of the peptide. In effect, the most efficient inhibitor was a cationic receptor Cvia extended aromatic interactions. These results highlight the potential of versatile and tunable functionalized resorcinarenes as potential therapeutics to reverse the aggregation of α-crystallin dominant in eye cataracts.

TAR DNA‐binding protein‐43 (TDP‐43) proteinopathy has been linked to several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) [1]. TDP‐43 is a protein that functions in transcriptional repression, the modulation of RNA metabolism, and stress granule formation within cells. As in the case with many other proteins that are partially destructed, characterization of full‐length recombinant TDP‐43 has proved difficult. This protein is commonly modified post‐translationally (PTMs) into aggregated and mutated structures in the cytoplasm and nucleus, including phosphorylation, acetylation, and C‐terminal cleavages [2]. Cytoplasmic mislocalization and post‐translational modifications of TDP‐43 have been linked to aggregate formation, proposedly important for TDP‐43‐toxicity mechanisms [3, 4]. Since pertinent research has only recently been established on the protein, the pathogenicity and functionality of TDP‐43 in ALS has yet to be determined, thus providing us with a critical knowledge gap in TDP‐43's functions. Thus, systematic in vitro studies were conducted in our lab to characterize the basic aggregation mechanisms of full‐length, native TDP‐43 and establish a working model for the in vitro analyses of the protein. Current research on the full‐length protein have discovered notable findings regarding the intermolecular properties of TDP‐43, providing critical insight into the hydrophobicity of its structure. Along with these intermolecular characteristics and its poor solubility in vitro , the full structure of TDP‐43 has not been fully defined. Herein, the in vitro aggregation of TDP‐43 protein was achieved and characterized using various spectroscopic methods and electron microscopy. Data indicate that TDP‐43 protein is an inherently aggregation‐prone protein from the application of several in vitro conditions to induce misfolding of the protein, followed by turbidity and Thioflavin T (ThT) fluorescence assays to monitor β‐sheet formation. Transmission electron microscopy (TEM) allowed for visualization of the structural morphologies of these TDP‐43 aggregates. As a result, data indicate that full‐length TDP‐43 protein aggregated under specific environmental conditions and resulted in a high turbidity and ThT intensity. The in vitro analysis of TDP‐43 aggregation is a valuable model for future protein studies and provides a preliminary platform for screening therapies towards a viable treatment for ALS. References: 1. Renaud L, Picher‐Martel V, Codron P, Julien JP (2019) Acta Neuropathol Commun 7:1–11. 2. Arai T, Hasegawa M, Akiyama H, et al (2006) Biochem Biophys Res Commun 351:602–611. 3. Sackmann C, Sackmann V, Hallbeck M (2020) Front Neurosci 14:1–14. 4. Afroz T, Hock EM, Ernst P, et al (2017) Nat Commun 8:1–14