Ofloxacin as a Disruptor of Actin Aggresome "Hirano Bodies": A Potential Repurposed Drug for the Treatment of Neurodegenerative Diseases

Ophthalmic drug effects on the amyloidogenesis of a transforming growth factor β-induced protein (TGFBIp) peptide fragment

Drugs that can treat one disease may either be detrimental or beneficial toward another due to possible cross-interactions. Therefore, care in choosing a suitable drug for patients with multiple diseases is crucial in successful patient management. This study explores several currently available ophthalmic drugs used to treat common ocular diseases to understand how they can affect the amyloidogenesis of a transforming growth factor β-induced protein (TGFBIp) peptide fragment found in abundance in the corneal protein aggregation deposits of lattice corneal dystrophy (LCD) patients. Results from this study provided supporting evidence that some drugs intended to treat other diseases can enhance or inhibit fibrillar aggregation of TGFBIp peptide, which may have potential implication of affecting the disease progression of LCD by either worsening or ameliorating it. Comparisons of the different properties of ophthalmic compounds explored in this study may also provide some guidance for future design of drugs geared toward the treatment of LCD.

Revisiting the relevance of Hirano bodies in neurodegenerative diseases

AIMS

Hirano bodies (HBs) are eosinophilic pathological structures with two morphological phenotypes commonly found in the hippocampal CA1 region in Alzheimer's disease (AD). This study evaluated the prevalence and distribution of HBs in AD and other neurodegenerative diseases.

METHODS

This cross-sectional study systematically evaluated HBs in a cohort of 193 cases with major neurodegenerative diseases, including AD (n = 91), Lewy body disease (LBD, n = 87), progressive supranuclear palsy (PSP, n = 36), multiple system atrophy (MSA, n = 14) and controls (n = 26). The prevalence, number and morphology of HBs in the stratum lacunosum (HBL) and CA1 pyramidal cell layer were examined. In addition, we investigated the presence of HBs in five additional hippocampal subregions.

RESULTS

The morphological types of HBs in CA1 were divided into three, including a newly discovered type, and were evaluated separately, with their morphology confirmed in three dimensions: (1) classic rod-shaped HB (CHB), (2) balloon-shaped HB (BHB) and the newly described (3) string-shaped HB (SHB). The prevalence of each HB type differed between disease groups: Compared with controls, for CHB in AD, AD + LBD, PSP and corticobasal degeneration, for BHB in AD + LBD and PSP, and SHB in AD + LBD and PSP were significantly increased. Regression analysis showed that CHBs were independently associated with higher Braak NFT stage, BHBs with LBD and TDP-43 pathology, SHBs with higher Braak NFT stage, PSP and argyrophilic grain disease and HBLs with MSA.

CONCLUSIONS

This study demonstrates that HBs are associated with diverse neurodegenerative diseases and shows that morphological types appear distinctively in various conditions.

Macromolecular structures and proteins interacting with the microtubule associated tau protein

It is well established that neurodegenerative diseases known as tauopathies are characterized by the presence of filamentous forms of phosphorylated tau protein inside neurons. However, the causal relationship between the initial symptoms of a particular disease and the molecular events affecting tau and leading to the appearance of tangles of filamentous forms of this protein remains unknown. Even the main function (or functions) of tau inside neurons is debatable and controversial. Tau seems to be a multifunctional protein. I review here some of the most studied interactions of tau with different macromolecules and proteins, which can be classified according to the structural o functional unit within which the interaction works: Microtubule, Nuclear localization and DNA, Synaptic activity, RNA metabolism, Fats transport, Proteostasis, Amyloid Cascade Hypothesis, Mitochondria and Phosphorylation. Although this seems to be a broad spectrum of tau functions, interactome studies of tau reveal hundreds of plausible partners of tau, suggesting that it engages in an extensive network of interconnected regulatory interactions by means of its high capability to interact with all kinds of proteins and complex structures, combined with its vast number of post-translational modifications. I include also some thermodynamic data concerning the interaction of tau with some partners.

Microscopic studies on severing properties of actin-binding protein: its potential use in therapeutic treatment of actin-rich inclusions

Actin is an important unit of the cytoskeletal system, involved in many cellular processes including cell motility, signaling, and intracellular trafficking. Various studies have been undertaken to understand the regulatory mechanisms pertaining actin functions, especially the ones controlled by actin-binding proteins. However, not much has been explored about the molecular aspects of these proteins implicated in various diseases. In this study, we aimed to demonstrate the molecular properties of gelsolin, an actin-severing protein on the disassembly of the aggregation of actin-rich intracellular inclusions, Hirano body. We observed a decreasing tendency of actin aggregation by co-sedimentation assay and transmission electron microscopy in the presence of gelsolin. Therefore, we provide suggestive evidence for the use of actin-severing protein in novel therapeutic strategies for neurodegenerative conditions.