Pathogenic Tau Protein Species: Promising Therapeutic Targets for Ocular Neurodegenerative Diseases

Expression Profiling of ADAMTS (L) Superfamily of Genes in Various Human Eye Tissues

Background

A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) is a superfamily of extracellular proteinases found in both mammals and invertebrates. Although there is some evidence about the role of ADAMTSs in ocular diseases such as glaucoma and ectopia lentis, but there is little information about the expression patterns of ADAMTS-1-20 and ADAMTS-like (ADAMTSL-1-6 and PAPLN) genes in human ocular tissues. This study aimed to evaluate the expression profiling of ADAMTS(L) superfamily of genes in different ocular tissues based on age.

Methods

In 2019, nine human donated eye globes were provided from the Central Eye Bank of Iran, and were divided into three different groups based on age (under 3 yr old, between 20 to 50 and upper 50 yr old). To assess expression patterns of ADAMTS(L) genes in different ocular tissues including trabecular meshwork, lens, retinal pigment epithelium, macula, and optic nerve in the three age groups, total RNA was extracted from the tissues and reverse transcription polymerase chain reaction followed by Real-time PCR was performed.

Results

We demonstrated not only each member of ADAMTS(L) superfamily shows different expression pattern between the five investigated ocular tissues, but also some members have differential expressions among the investigated age groups in same tissues.

Conclusion

Differential expression of ADAMTS(L) genes in ocular tissues from different age groups could explain some functional aspects of the tissues and also may be used as prognostic and diagnostic biomarkers for ocular diseases and pathologies. Further studies are required to explore their functional roles associated with ocular pathologies.

Lactobacillaceae improve cognitive dysfunction via regulating gut microbiota and suppressing Aβ deposits and neuroinflammation in APP/PS1 mice

Alzheimer's disease (AD), the most prevalent neurodegenerative disease, has a significant relationship with alteration of the gut microbiota (GM), and the GM-gut-brain axis has been explored to find novel therapeutic approaches for AD. The present study aimed to evaluate the effect of human Lactobacillaceae (HLL) on cognitive function in APP/PS1 mice. The results showed that HLL treatment significantly improved the cognitive function of mice via MWM and NOR tests. Furthermore, the expression of Aβ plaques, tau phosphorylation and neuroinflammation were markedly reduced in the hippocampus. Meanwhile, HLL treatment significantly increased the activity of GSH-PX and decreased the expression levels of IL-6 and MDA in the brain, and simultaneously increased the abundance of beneficial bacteria and restrained pathogenic bacteria in the intestine. Interestingly, significant correlations were observed between significant changes in abundance of GMs and AD-related markers. Collectively, these findings reveal that HLL is a promising therapeutic agent and potential probiotics, which might improve the cognitive function and AD pathologies.

Cellular Reprogramming and Its Potential Application in Alzheimer’s Disease

Alzheimer’s disease (AD) has become the most common age-related dementia in the world and is currently incurable. Although many efforts have been made, the underlying mechanisms of AD remain unclear. Extracellular amyloid-beta deposition, intracellular tau hyperphosphorylation, neuronal death, glial cell activation, white matter damage, blood–brain barrier disruption, and other mechanisms all take part in this complicated disease, making it difficult to find an effective therapy. In the study of therapeutic methods, how to restore functional neurons and integrate myelin becomes the main point. In recent years, with the improvement and maturity of induced pluripotent stem cell technology and direct cell reprogramming technology, it has become possible to induce non-neuronal cells, such as fibroblasts or glial cells, directly into neuronal cells in vitro and in vivo. Remarkably, the induced neurons are functional and capable of entering the local neural net. These encouraging results provide a potential new approach for AD therapy. In this review, we summarized the characteristics of AD, the reprogramming technique, and the current research on the application of cellular reprogramming in AD. The existing problems regarding cellular reprogramming and its therapeutic potential for AD were also reviewed.

IMB5036, a novel pyridazinone compound, inhibits hepatocellular carcinoma growth and metastasis

Background Hepatocellular carcinoma (HCC) is one of the most common cancers with a high mortality rate due to metastasis and relapse. Purpose Here, we reported a small-molecule pyridazinone compound, designated as IMB5036. Its antitumor activity against HCC and underlying mechanism were studied. Methods In vitro cytotoxicity, apoptosis, DNA breaks, and cell motility assays were performed. Protein expression was analyzed by Western blot and microarray analysis. A xenograft tumor model in athymic mice was used to evaluate the antitumor activity. Results IMB5036 displayed potent cytotoxicity against various HCC cell lines. It caused double DNA breakages and induced cell death via apoptosis. It also significantly inhibited the motility of HCC cells. Western blot showed that IMB5036 induced the up-regulation of E-cadherin, while down-regulation of N-cadherin. The gene expression profile analysis and Western blot assay revealed that IMB5036 down-regulated the expression of Tau protein. Analysis of the TCGA dataset revealed that high expression of Tau decreased the survival rate of HCC patients. In vivo experiments proved that IMB5036 significantly inhibited the growth of HCC xenografts in athymic mice. Conclusions These results collectively demonstrate IMB5036 can be a promising therapeutic candidate for patients with HCC.

Melatonin: Regulation of Biomolecular Condensates in Neurodegenerative Disorders

Biomolecular condensates are membraneless organelles (MLOs) that form dynamic, chemically distinct subcellular compartments organizing macromolecules such as proteins, RNA, and DNA in unicellular prokaryotic bacteria and complex eukaryotic cells. Separated from surrounding environments, MLOs in the nucleoplasm, cytoplasm, and mitochondria assemble by liquid-liquid phase separation (LLPS) into transient, non-static, liquid-like droplets that regulate essential molecular functions. LLPS is primarily controlled by post-translational modifications (PTMs) that fine-tune the balance between attractive and repulsive charge states and/or binding motifs of proteins. Aberrant phase separation due to dysregulated membrane lipid rafts and/or PTMs, as well as the absence of adequate hydrotropic small molecules such as ATP, or the presence of specific RNA proteins can cause pathological protein aggregation in neurodegenerative disorders. Melatonin may exert a dominant influence over phase separation in biomolecular condensates by optimizing membrane and MLO interdependent reactions through stabilizing lipid raft domains, reducing line tension, and maintaining negative membrane curvature and fluidity. As a potent antioxidant, melatonin protects cardiolipin and other membrane lipids from peroxidation cascades, supporting protein trafficking, signaling, ion channel activities, and ATPase functionality during condensate coacervation or dissolution. Melatonin may even control condensate LLPS through PTM and balance mRNA- and RNA-binding protein composition by regulating N6-methyladenosine (m6A) modifications. There is currently a lack of pharmaceuticals targeting neurodegenerative disorders via the regulation of phase separation. The potential of melatonin in the modulation of biomolecular condensate in the attenuation of aberrant condensate aggregation in neurodegenerative disorders is discussed in this review.

Redox Homeostasis and Prospects for Therapeutic Targeting in Neurodegenerative Disorders

Reactive species, such as those of oxygen, nitrogen, and sulfur, are considered part of normal cellular metabolism and play significant roles that can impact several signaling processes in ways that lead to either cellular sustenance, protection, or damage. Cellular redox processes involve a balance in the production of reactive species (RS) and their removal because redox imbalance may facilitate oxidative damage. Physiologically, redox homeostasis is essential for the maintenance of many cellular processes. RS may serve as signaling molecules or cause oxidative cellular damage depending on the delicate equilibrium between RS production and their efficient removal through the use of enzymatic or nonenzymatic cellular mechanisms. Moreover, accumulating evidence suggests that redox imbalance plays a significant role in the progression of several neurodegenerative diseases. For example, studies have shown that redox imbalance in the brain mediates neurodegeneration and alters normal cytoprotective responses to stress. Therefore, this review describes redox homeostasis in neurodegenerative diseases with a focus on Alzheimer's and Parkinson's disease. A clearer understanding of the redox-regulated processes in neurodegenerative disorders may afford opportunities for newer therapeutic strategies.

Recent Advances in Nanotechnology: A Novel Therapeutic System for the Treatment of Alzheimer's Disease

A amyloid-β (Aβ) plaque formation in the brain is known to be the root cause of Alzheimer's disease (AD), which affects the behavior, memory, and cognitive ability in humans. The brain starts undergoing changes several years before the actual appearance of the symptoms. Nanotechnology could prove to be an alternative strategy for treating the disease effectively. It encompasses the diagnosis as well as the therapeutic aspect using validated biomarkers and nano-based drug delivery systems, respectively. A nano-based therapy may provide an alternate strategy, wherein one targets the protofibrillar amyloid-β (Aβ) structures, and this is followed by their disaggregation as random coils. Conventional/routine drug therapies are inefficient in crossing the blood-brain barrier; however, this hurdle can be overcome with the aid of nanoparticles. The present review highlights the various challenges in the diagnosis and treatment of AD. Meticulous and collaborative research using nanotherapeutic systems could provide remarkable breakthroughs in the early-stage diagnosis and therapy of AD.