Monitoring autophagy in the treatment of protein aggregate diseases: steps toward identifying autophagic biomarkers

Exploring molecular mechanisms, therapeutic strategies, and clinical manifestations of Huntington's disease

Huntington's disease (HD) is a paradigm of a genetic neurodegenerative disorder characterized by the expansion of CAG repeats in the HTT gene. This extensive review investigates the molecular complexities of HD by highlighting the pathogenic mechanisms initiated by the mutant huntingtin protein. Adverse outcomes of HD include mitochondrial dysfunction, compromised protein clearance, and disruption of intracellular signaling, consequently contributing to the gradual deterioration of neurons. Numerous therapeutic strategies, particularly precision medicine, are currently used for HD management. Antisense oligonucleotides, such as Tominersen, play a leading role in targeting and modulating the expression of mutant huntingtin. Despite the promise of these therapies, challenges persist, particularly in improving delivery systems and the necessity for long-term safety assessments. Considering the future landscape, the review delineates promising directions for HD research and treatment. Innovations such as Clustered regularly interspaced short palindromic repeats associated system therapies (CRISPR)-based genome editing and emerging neuroprotective approaches present unprecedented opportunities for intervention. Collaborative interdisciplinary endeavors and a more insightful understanding of HD pathogenesis are on the verge of reshaping the therapeutic landscape. As we navigate the intricate landscape of HD, this review serves as a guide for unraveling the intricacies of this disease and progressing toward transformative treatments.

Interleukin 7 inhibit autophagy via P53 regulated AMPK/mTOR signaling pathway in non-small cell lung cancer

Interleukin 7 (IL-7) has been demonstrated regulating lymphangiogenesis, apoptosis, and proliferation. Whether IL-7 induce or inhibit autophagy in non-small cell lung cancer (NSCLC) are unknown. In this study, Western blot was used to detect cytoplasmic and nuclear protein of p53, total protein of AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and Light chain 3 (LC3). Quantitative Real-Time PCR (qRT-PCR) was used to detect p53 mRNA level after treated with IL-7. Then using transmission electron microscopy to observe the morphological change of autophagosome. 123 cases of NSCLC were collected for survival analysis, immunohistochemistry staining and cox regression multivariate analysis. We find that IL-7 induce the p53 translocation from nucleus to cytoplasm, then IL-7 down-regulate phosphorylation of AMPK and up-regulate phosphorylation of mTOR. The expression of AMPK and p53 were associated with IL-7/IL-7R and mTOR expression. Clinically, AMPK and p53 were well correlated with stage and survival of lung cancer patients. IL-7R, mTOR and tumor stage were the strongest predictors of survival. In conclusion, IL-7 inhibit autophagy in NSCLC via P53 regulated AMPK/mTOR signaling pathway. AMPK and p53 are correlated with patients’ survival. IL-7R, mTOR and tumor stage are the strongest predictor of survival.

New Avenues for the Treatment of Huntington's Disease

Huntington’s disease (HD) is a neurodegenerative disorder caused by a CAG expansion in the HD gene. The disease is characterized by neurodegeneration, particularly in the striatum and cortex. The first symptoms usually appear in mid-life and include cognitive deficits and motor disturbances that progress over time. Despite being a genetic disorder with a known cause, several mechanisms are thought to contribute to neurodegeneration in HD, and numerous pre-clinical and clinical studies have been conducted and are currently underway to test the efficacy of therapeutic approaches targeting some of these mechanisms with varying degrees of success. Although current clinical trials may lead to the identification or refinement of treatments that are likely to improve the quality of life of those living with HD, major efforts continue to be invested at the pre-clinical level, with numerous studies testing novel approaches that show promise as disease-modifying strategies. This review offers a detailed overview of the currently approved treatment options for HD and the clinical trials for this neurodegenerative disorder that are underway and concludes by discussing potential disease-modifying treatments that have shown promise in pre-clinical studies, including increasing neurotropic support, modulating autophagy, epigenetic and genetic manipulations, and the use of nanocarriers and stem cells.

Inhibitory Effects of Dopamine Receptor D1 Agonist on Mammary Tumor and Bone Metastasis

Dopaminergic signaling plays a critical role in the nervous system, but little is known about its potential role in breast cancer and bone metabolism. A screening of ~1,000 biologically active compounds revealed that a selective agonist of dopamine receptor D1 (DRD1), A77636, inhibited proliferation of 4T1.2 mammary tumor cells as well as MDA-MB-231 breast cancer cells. Herein, we examined the effect of A77636 on bone quality using a mouse model of bone metastasis from mammary tumor. A77636 inhibited migration of cancer cells in a DRD1-dependent fashion and suppressed development of bone-resorbing osteoclasts by downregulating NFATc1 through the elevation of phosphorylation of eIF2α. In the mouse model of bone metastasis, A77636 reduced osteolytic lesions and prevented mechanical weakening of the femur and tibia. Collectively, we expect that dopaminergic signaling might provide a novel therapeutic target for breast cancer and bone metastasis.

Autophagy and Tubular Cell Death in the Kidney

Many common renal insults such as ischemia and toxic injury primarily target the tubular epithelial cells, especially the highly metabolically active proximal tubular segment. Tubular epithelial cells are particularly dependent on autophagy to maintain homeostasis and respond to stressors. The pattern of autophagy in the kidney has a unique spatial and chronologic signature. Recent evidence has shown that there is complex cross-talk between autophagy and various cell death pathways. This review specifically discusses the interplay between autophagy and cell death in the renal tubular epithelia. It is imperative to review this topic because recent discoveries have improved our mechanistic understanding of the autophagic process and have highlighted its broad clinical applications, making autophagy a major target for drug development.

TFEB Participates in the Aβ-Induced Pathogenesis of Alzheimer's Disease by Regulating the Autophagy-Lysosome Pathway

To investigate whether transcriptional factor EB (TFEB) participates in amyloid-β(1-42) (Aβ(1-42))-induced pathogenesis of Alzheimer's disease (AD) and its underlying mechanisms. Three-month-old and 8-month-old transgenic APP/PS1 AD mice and age-matched wild mice were used in this study. We found that the 8-month-old AD animals presented significantly higher deposition of Aβ(1-42) and expression of TFEB and its targeted proteins, such as LAMP-1 and cathepsin D, and autophagy-associated LC3-II and p62 in brain tissues than in others. In an in vitro study, TFEB overexpression rescued autophagic flux that blocked by Aβ(1-42) and the degradation of the absorbed Aβ(1-42), relieved Aβ(1-42)-mediated induction of overloaded autophagy. In addition, TFEB overexpression enhanced cathepsin D expression and activity, restored Aβ(1-42)-disturbed acid environment of lysosome, and promoted the fusion of autophagosomes with lysosomes. Furthermore, TFEB upregulation reduced Aβ(1-42)-induced production of malondialdehyde, oxidative carbonyl proteins, and reactive oxygen species (ROS) and cell apoptosis mainly dependent on the removal of Aβ(1-42) by the autophagy-lysosome pathway. TFEB overexpression alleviated AD progression by reducing Aβ accumulation through regulating the autophagy-lysosome pathway and reducing Aβ-induced ROS production and cell apoptosis.

Multispectral Bayesian reconstruction technique for real-time two color fluorescence microscopy

We have developed a real-time imaging method for two-color widefield fluorescence microscopy using a combined approach that integrates multi-spectral imaging and Bayesian image reconstruction technique.

Maintenance of basal levels of autophagy in Huntington's disease mouse models displaying metabolic dysfunction

Huntington's disease (HD) is a fatal neurodegenerative disorder caused by an expanded polyglutamine repeat in the huntingtin protein. Neuropathology in the basal ganglia and in the cerebral cortex has been linked to the motor and cognitive symptoms whereas recent work has suggested that the hypothalamus might be involved in the metabolic dysfunction. Several mouse models of HD that display metabolic dysfunction have hypothalamic pathology, and expression of mutant huntingtin in the hypothalamus has been causally linked to the development of metabolic dysfunction in mice. Although the pathogenic mechanisms by which mutant huntingtin exerts its toxic functions in the HD brain are not fully known, several studies have implicated a role for the lysososomal degradation pathway of autophagy. Interestingly, changes in autophagy in the hypothalamus have been associated with the development of metabolic dysfunction in wild-type mice. We hypothesized that expression of mutant huntingtin might lead to changes in the autophagy pathway in the hypothalamus in mice with metabolic dysfunction. We therefore investigated whether there were changes in basal levels of autophagy in a mouse model expressing a fragment of 853 amino acids of mutant huntingtin selectively in the hypothalamus using a recombinant adeno-associate viral vector approach as well as in the transgenic BACHD mice. We performed qRT-PCR and Western blot to investigate the mRNA and protein expression levels of selected autophagy markers. Our results show that basal levels of autophagy are maintained in the hypothalamus despite the presence of metabolic dysfunction in both mouse models. Furthermore, although there were no major changes in autophagy in the striatum and cortex of BACHD mice, we detected modest, but significant differences in levels of some markers in mice at 12 months of age. Taken together, our results indicate that overexpression of mutant huntingtin in mice do not significantly perturb basal levels of autophagy.

Accelerating the clearance of mutant huntingtin protein aggregates through autophagy induction by europium hydroxide nanorods

Autophagy is one of the well-known pathways to accelerate the clearance of protein aggregates, which contributes to the therapy of neurodegenerative diseases. Although there are numerous reports that demonstrate the induction of autophagy with small molecules including rapamycin, trehalose and lithium, however, there are few reports mentioning the clearance of aggregate-prone proteins through autophagy induction by nanoparticles. In the present article, we have demonstrated that europium hydroxide [Eu(III)(OH)3] nanorods can reduce huntingtin protein aggregation (EGFP-tagged huntingtin protein with 74 polyQ repeats), responsible for neurodegenerative diseases. Again, we have found that these nanorods induce authentic autophagy flux in different cell lines (Neuro 2a, PC12 and HeLa cells) through the expression of higher levels of characteristic autophagy marker protein LC3-II and degradation of selective autophagy substrate/cargo receptor p62/SQSTM1. Furthermore, depression of protein aggregation clearance through the autophagy blockade has also been observed by using specific inhibitors (wortmannin and chloroquine), indicating that autophagy is involved in the degradation of huntingtin protein aggregation. Since [Eu(III)(OH)3] nanorods can enhance the degradation of huntingtin protein aggregation via autophagy induction, we strongly believe that these nanorods would be useful for the development of therapeutic treatment strategies for various neurodegenerative diseases in near future using nanomedicine approach.