Crosstalk between the Hippo Pathway and the Wnt Pathway in Huntington's Disease and Other Neurodegenerative Disorders

MST1 selective inhibitor Xmu-mp-1 ameliorates neuropathological changes in a rat model of sporadic Alzheimer's Disease by modulating Hippo-Wnt signaling crosstalk

Alzheimer's disease (AD), the most prevalent form of dementia, is characterized by progressive cognitive impairment accompanied by aberrant neuronal apoptosis. Reports suggest that the pro-apoptotic mammalian set20-like kinase 1/2 (MST1/2) instigates neuronal apoptosis via activating the Hippo signaling pathway under various stress conditions, including AD. However, whether inhibiting MST1/2 has any therapeutic benefits in AD remains unknown. Thus, we tested the therapeutic effects of intervening MST1/2 activation via the pharmacological inhibitor Xmu-mp-1 in a sporadic AD rat model. Sporadic AD was established in adult rats by intracerebroventricular streptozotocin (ICV-STZ) injection (3 mg/kg body weight). Xmu-mp-1 (0.5 mg/kg/body weight) was administered once every 48 h for two weeks, and Donepezil (5 mg/kg body weight) was used as a reference standard drug. The therapeutic effects of Xmu-mp-1 on ICV-STZ rats were determined through various behavioral, biochemical, histopathological, and molecular tests. At the behavioral level, Xmu-mp-1 improved cognitive deficits in sporadic AD rats. Further, Xmu-mp-1 treatment reduced STZ-associated tau phosphorylation, amyloid-beta deposition, oxidative stress, neurotoxicity, neuroinflammation, synaptic dysfunction, neuronal apoptosis, and neurodegeneration. Mechanistically, Xmu-mp-1 exerted these neuroprotective actions by inactivating the Hippo signaling while potentiating the Wnt/β-Catenin signaling in the AD rats. Together, the results of the present study provide compelling support that Xmu-mp-1 negated the neuronal dysregulation in the rat model of sporadic AD. Therefore, inhibiting MST/Hippo signaling and modulating its crosstalk with the Wnt/β-Catenin pathway can be a promising alternative treatment strategy against AD pathology. This is the first study providing novel mechanistic insights into the therapeutic use of Xmu-mp-1 in sporadic AD.

Unlocking Hope: Therapeutic Advances and Approaches in Modulating the Wnt Pathway for Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are conditions characterized by sensory, motor, and cognitive impairments due to alterations in the structure and function of neurons in the central nervous system (CNS). Despite their widespread occurrence, the exact causes of NDs remain largely elusive, and existing treatments fall short in efficacy. The Wnt signaling pathway is an emerging molecular pathway that has been linked to the development and progression of various NDs. Wnt signaling governs numerous cellular processes, such as survival, polarity, proliferation, differentiation, migration, and fate specification, via a complex network of proteins. In the adult CNS, Wnt signaling regulates synaptic transmission, plasticity, memory formation, neurogenesis, neuroprotection, and neuroinflammation, all essential for maintaining neuronal function and integrity. Dysregulation of both canonical and non-canonical Wnt signaling pathways contributes to neurodegeneration through various mechanisms, such as amyloid-β accumulation, tau protein hyperphosphorylation, dopaminergic neuron degeneration, and synaptic dysfunction, prompting investigations into Wnt modulation as a therapeutic target to restore neuronal function and prevent or delay neurodegenerative processes. Modulating Wnt signaling has the potential to restore neuronal function and impede or postpone neurodegenerative processes, offering a therapeutic approach for targeting NDs. In this article, the current knowledge about how Wnt signaling works in Alzheimer's disease and Parkinson's disease is discussed. Our study aims to explore the molecular mechanisms, recent discoveries, and challenges involved in developing Wnt-based therapies.

Wnt/β-Catenin Signaling Regulates Yap/Taz Activity during Embryonic Development in Zebrafish

Hippo-YAP/TAZ and Wnt/β-catenin signaling pathways, by controlling proliferation, migration, cell fate, stemness, and apoptosis, are crucial regulators of development and tissue homeostasis. We employed zebrafish embryos as a model system to elucidate in living reporter organisms the crosstalk between the two signaling pathways. Co-expression analysis between the Wnt/β-catenin Tg(7xTCF-Xla.Siam:GFP)ia4 and the Hippo-Yap/Taz Tg(Hsa.CTGF:nlsmCherry)ia49 zebrafish reporter lines revealed shared spatiotemporal expression profiles. These patterns were particularly evident in key developmental regions such as the midbrain-hindbrain boundary (MHB), epidermis, muscles, neural tube, notochord, floorplate, and otic vesicle. To investigate the relationship between the Wnt/β-catenin pathway and Hippo-Yap/Taz signaling in vivo, we conducted a series of experiments employing both pharmacological and genetic strategies. Modulation of the Wnt/β-catenin pathway with IWR-1, XAV939, or BIO resulted in a significant regulation of the Yap/Taz reporter signal, highlighting a clear correlation between β-catenin and Yap/Taz activities. Furthermore, genetic perturbation of the Wnt/β-catenin pathway, by APC inhibition or DKK1 upregulation, elicited evident and robust alteration of Yap/Taz activity. These findings revealed the intricate regulatory mechanisms underlying the crosstalk between the Wnt/β-catenin and Hippo-Yap/Taz signaling, shedding light on their roles in orchestrating developmental processes in vivo.

Wnt/β-catenin signaling pathway in carcinogenesis and cancer therapy

The Wnt/β-catenin signaling pathway plays a crucial role in various physiological processes, encompassing development, tissue homeostasis, and cell proliferation. Under normal physiological conditions, the Wnt/β-catenin signaling pathway is meticulously regulated. However, aberrant activation of this pathway and downstream target genes can occur due to mutations in key components of the Wnt/β-catenin pathway, epigenetic modifications, and crosstalk with other signaling pathways. Consequently, these dysregulations contribute significantly to tumor initiation and progression. Therapies targeting the Wnt/β-catenin signaling transduction have exhibited promising prospects and potential for tumor treatment. An increasing number of medications targeting this pathway are continuously being developed and validated. This comprehensive review aims to summarize the latest advances in our understanding of the role played by the Wnt/β-catenin signaling pathway in carcinogenesis and targeted therapy, providing valuable insights into acknowledging current opportunities and challenges associated with targeting this signaling pathway in cancer research and treatment.

Identification of different subtypes of ovarian cancer and construction of prognostic models based on glutamine-metabolism associated genes

Ovarian cancer (OC) is common malignant tumor of female reproductive system. Glutamine metabolism-related genes (GMRGs) play a key role in ovarian cancer. Here, available database-- The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Gene Expression Omnibus (GEO) databases were applied in our research. OC samples from TCGA were divided into different clusters based on Cox analysis, which filtering GMRGs with survival information. Then, differentially expressed genes (DEGs) between these clusters were intersected with DEGs between normal ovary samples and OC samples, and GMRGs in order to obtain GMRGs-related DEGs. Next, a risk model of OC was constructed and enrichment analysis of risk model was performed based on hallmark gene set. Besides, the immune cells ratio in OC samples were detected via Cell type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT). Finally, we explored a series of potential biomarkers of OC. In this research, 9 GMRGs-related DEGs were obtained. GMRGs-related DEGs were enriched to canonical Wnt signaling pathway.NKD2, C2orf88, and KLHDC8A, which were significantly associated with prognosis, were retained for risk model construction. Based on the risk model, 18 hallmark pathways with significant difference were enriched. Fifteen types of immune cells (such as iDC, NK CD56dim cells, and neutrophils) enjoying significant difference between these 2 risk groups (high risk group vs. low risk group) were detected, which indicates possible disparate TME in different metabolic subtypes of ovarian cancer.

Synaptic dysfunction and extracellular matrix dysregulation in dopaminergic neurons from sporadic and E326K-GBA1 Parkinson's disease patients

Parkinson's disease (PD) is a neurodegenerative disease with both genetic and sporadic origins. In this study, we investigated the electrophysiological properties, synaptic activity, and gene expression differences in dopaminergic (DA) neurons derived from induced pluripotent stem cells (iPSCs) of healthy controls, sporadic PD (sPD) patients, and PD patients with E326K-GBA1 mutations. Our results demonstrate reduced sodium currents and synaptic activity in DA neurons derived from PD patients with E326K-GBA1 mutations, suggesting a potential contribution to PD pathophysiology. We also observed distinct electrophysiological alterations in sPD DA neurons, which included a decrease in synaptic currents. RNA sequencing analysis revealed unique dysregulated pathways in sPD neurons and E326K-GBA1 neurons, further supporting the notion that molecular mechanisms driving PD may differ between PD patients. In agreement with our previous reports, Extracellular matrix and Focal adhesion pathways were among the top dysregulated pathways in DA neurons from sPD patients and from patients with E326K-GBA1 mutations. Overall, our study further confirms that impaired synaptic activity is a convergent functional phenotype in DA neurons derived from PD patients across multiple genetic mutations as well as sPD. At the transcriptome level, we find that the brain extracellular matrix is highly involved in PD pathology across multiple PD-associated mutations as well as sPD.

Oleanolic acid, a small-molecule natural product, inhibits ECM degeneration in osteoarthritis by regulating the Hippo/YAP and Wnt/β-catenin pathways

Over the past few decades, osteoarthritis (OA) has been a major health problem worldwide. It is urgent to develop new, effective, and safe drugs to treat OA. There are many pentacyclic triterpenoids in nature that are safe and have health benefits. Oleanolic acid (OLA), one of the pentacyclic triterpenoids, is a potential novel compound for treating OA; however, its mechanism of action is still unclear. In this study, the mechanism of resistance to extracellular matrix (ECM) degradation of OLA and its protective role in the amelioration of OA were investigated by in vivo and in vitro experiments. We found that OLA promoted interleukin-1β (IL-1β)-induced production of type II collagen (collagen II) in rat chondrocytes, decreased the expression of matrix metalloproteinase (MMP)-3 and MMP-13, and inhibited inflammatory cytokine (IL-1β and TNF-α) and cartilage marker (CTX-II and COMP) levels, thereby hindering the pathological process of cartilage. Mechanistically, OLA inhibited the Wnt/β-catenin pathway, activated the Hippo/YAP pathway, and hampered the ECM degradation process by inhibiting the nuclear translocation of β-catenin and YAP. When we knocked down β-catenin, OLA lost its stimulatory effect on the Hippo pathway. These findings confirm that OLA plays an anti-ECM degradation role by regulating the Wnt/β-catenin and Hippo/YAP pathways. Overall, this study provides a theoretical basis for developing highly effective and low-toxic natural products for the prevention and treatment of OA.

Investigating Neuron Degeneration in Huntington's Disease Using RNA-Seq Based Transcriptome Study

Huntington's disease (HD) is a progressive neurodegenerative disorder caused due to a CAG repeat expansion in the huntingtin (HTT) gene. The primary symptoms of HD include motor dysfunction such as chorea, dystonia, and involuntary movements. The primary motor cortex (BA4) is the key brain region responsible for executing motor/movement activities. Investigating patient and control samples from the BA4 region will provide a deeper understanding of the genes responsible for neuron degeneration and help to identify potential markers. Previous studies have focused on overall differential gene expression and associated biological functions. In this study, we illustrate the relationship between variants and differentially expressed genes/transcripts. We identified variants and their associated genes along with the quantification of genes and transcripts. We also predicted the effect of variants on various regulatory activities and found that many variants are regulating gene expression. Variants affecting miRNA and its targets are also highlighted in our study. Co-expression network studies revealed the role of novel genes. Function interaction network analysis unveiled the importance of genes involved in vesicle-mediated transport. From this unified approach, we propose that genes expressed in immune cells are crucial for reducing neuron death in HD.

Artemisia annua Extract Improves the Cognitive Deficits and Reverses the Pathological Changes of Alzheimer’s Disease via Regulating YAP Signaling

Alzheimer’s disease (AD) is a chronic neurodegenerative disease characterized by the occurrence of cognitive deficits. With no effective treatments available, the search for new effective therapies has become a major focus of interest. In the present study, we describe the potential therapeutic effect of Artemisia annua (A. annua) extract on AD. Nine-month-old female 3xTg AD mice were treated with A. annua extract for three months via oral administration. Animals assigned to WT and model groups were administrated with an equal volume of water for the same period. Treated AD mice significantly improved the cognitive deficits and exhibited reduced Aβ accumulation, hyper-phosphorylation of tau, inflammatory factor release and apoptosis when compared with untreated AD mice. Moreover, A. annua extract promoted the survival and proliferation of neural progenitor cells (NPS) and increased the expression of synaptic proteins. Further assessment of the implicated mechanisms revealed that A. annua extract regulates the YAP signaling pathway in 3xTg AD mice. Further studies comprised the incubation of PC12 cells with Aβ1–42 at a concentration of 8 μM with or without different concentrations of A. annua extract for 24 h. Obtained ROS levels, mitochondrial membrane potential, caspase-3 activity, neuronal cell apoptosis and assessment of the signaling pathways involved was performed using western blot and immunofluorescence staining. The obtained results showed that A. annua extract significantly reversed the Aβ1–42-induced increase in ROS levels, caspase-3 activity and neuronal cell apoptosis in vitro. Moreover, either inhibition of the YAP signaling pathway, using a specific inhibitor or CRISPR cas9 knockout of YAP gene, reduced the neuroprotective effect of the A. annua extract. These findings suggest that A. annua extract may be a new multi-target anti-AD drug with potential use in the prevention and treatment of AD.