Parkin Knockout Inhibits Neuronal Development via Regulation of Proteasomal Degradation of p21

SATB1, senescence and senescence-related diseases

Aging leads to an accumulation of cellular mutations and damage, increasing the risk of senescence, apoptosis, and malignant transformation. Cellular senescence, which is pivotal in aging, acts as both a guard against cellular transformation and as a check against cancer progression. It is marked by stable cell cycle arrest, widespread macromolecular changes, a pro-inflammatory profile, and altered gene expression. However, it remains to be determined whether these differing subsets of senescent cells result from unique intrinsic programs or are influenced by their environmental contexts. Multiple transcription regulators and chromatin modifiers contribute to these alterations. Special AT-rich sequence-binding protein 1 (SATB1) stands out as a crucial regulator in this process, orchestrating gene expression by structuring chromatin into loop domains and anchoring DNA elements. This review provides an overview of cellular senescence and delves into the role of SATB1 in senescence-related diseases. It highlights SATB1's potential in developing antiaging and anticancer strategies, potentially contributing to improved quality of life and addressing aging-related diseases.

Bifenthrin Caused Parkinson's-Like Symptoms Via Mitochondrial Autophagy and Ferroptosis Pathway Stereoselectively in Parkin-/- Mice and C57BL/6 Mice

It has been proposed that pyrethroid exposure contributes to the increasing prevalence of neurodegenerative diseases. However, the potential mechanisms remain unclear. The current study aimed to investigate the effects of the widely used pyrethroid bifenthrin on Parkinson's disease (PD) risk. Bifenthrin (1S-cis-bifenthrin, 1R-cis-bifenthrin, raceme) was administered to male Parkin-/- mice and C57BL/6 mice by oral gavage at a dose of 10 mg/kg bw/day for 28 days. Bifenthrin exposure significantly increased the time of pole climbing and decreased the period of rotarod running, indicating that bifenthrin decreased motor coordination in Parkin-/- mice, which was more evident by 1S-cis-bifenthrin. Furthermore, administration of bifenthrin induced obvious decreases in tyrosine hydroxylase (TH)+ cell count and the protein expression of TH. Increased protein of mitochondrial autophagy LC3B and p62 was observed after exposure to bifenthrin. Increased iron deposition and protein expression of iron transport transferrin (Tf) and transferrin receptor 2 (TfR2) was detected. 1S-cis-bifenthrin bound with Tf, TfR2, and GPX4 with lower binding energies than 1R-cis-bifenthrin, resulting in stronger interactions with these proteins. These results show structure-dependent PD-like effects of bifenthrin on motor activity and coordination associated with the disturbed mitochondrial autophagy and ferroptosis-related pathway. These data demonstrate that pyrethroid exposure increases the potential of Parkinson's-like symptoms via the ferroptosis pathway in Parkin-/- mice that is more pronounced than in C57BL/6 mice, providing a prospective enantioselective toxic effect of environmental neurotoxins on PD risk.

Discovery of Novel Indazole Chemotypes as Isoform-Selective JNK3 Inhibitors for the Treatment of Parkinson's Disease

c-Jun N-terminal kinases (JNKs) are involved in the pathogenesis of various diseases. In particular, JNK3 and not JNK1/2 is primarily expressed in the brain and plays a key role in mediating neurodegenerative diseases like Parkinson's disease (PD). Due to the sequence similarity of JNK isoforms, developing isoform-selective JNK3 inhibitors to evaluate their biological functions and therapeutic potential in PD has become a challenge. Herein, docking-based virtual screening and structure-activity relationship studies identified 25c with excellent inhibitory activity against JNK3 (IC₅₀ = 85.21 nM) and exhibited an over 100-fold isoform selectivity for JNK3 over JNK1/2 and remarkable kinase selectivity. 25c showed neuroprotective effects on in vitro and in vivo PD models by selectively inhibiting JNK3. Meanwhile, 25c showed an ideal blood-brain barrier permeability and low toxicity. Overall, this study provided a valuable molecular tool for investigating the role of JNK3 in PD and a solid foundation for developing JNK3-targeted drugs in PD treatment.

Neurogenesis in aging and age-related neurodegenerative diseases

Adult neurogenesis, the process by which neurons are generated in certain areas of the adult brain, declines in an age-dependent manner and is one potential target for extending cognitive healthspan. Aging is a major risk factor for neurodegenerative diseases and, as lifespans are increasing, these health challenges are becoming more prevalent. An age-associated loss in neural stem cell number and/or activity could cause this decline in brain function, so interventions that reverse aging in stem cells might increase the human cognitive healthspan. In this review, we describe the involvement of adult neurogenesis in neurodegenerative diseases and address the molecular mechanistic aspects of neurogenesis that involve some of the key aggregation-prone proteins in the brain (i.e., tau, Aβ, α-synuclein, …). We summarize the research pertaining to interventions that increase neurogenesis and regulate known targets in aging research, such as mTOR and sirtuins. Lastly, we share our outlook on restoring the levels of neurogenesis to physiological levels in elderly individuals and those with neurodegeneration. We suggest that modulating neurogenesis represents a potential target for interventions that could help in the fight against neurodegeneration and cognitive decline.

Parkin-deficient rats are resistant to neurotoxicity of chronic high-dose methamphetamine

Methamphetamine (METH) is a highly addictive and powerful central nervous system psychostimulant with no FDA-approved pharmacotherapy. Parkin is a neuroprotective protein and its loss of function contributes to Parkinson's disease. This study used 3-month-old homozygous parkin knockout (PKO) rats to determine whether loss of parkin protein potentiates neurotoxicity of chronic METH to the nigrostriatal dopamine pathway. PKO rats were chronically treated with 10 mg/kg METH for 10 consecutive days and assessed for neurotoxicity markers in the striatum on the 5th and 10th day of withdrawal from METH. The PKO rats showed higher METH-induced hyperthermia; however, they did not display augmented deficits in dopaminergic and serotonergic neurotoxicity markers, astrocyte activation or decreased mitochondrial enzyme levels as compared to wild-type (WT) rats. Interestingly, saline-treated PKO rats had lower levels of dopamine (DA) as well as mitochondrial complex I and II levels while having increased basal levels of glial fibrillary acidic protein (GFAP), a marker of gliosis. These results indicate PKO display a certain resistance to METH neurotoxicity, possibly mediated by lowered DA levels and downregulated mitochondria.

HJURP promotes proliferation in prostate cancer cells through increasing CDKN1A degradation via the GSK3β/JNK signaling pathway

Genes with cross-cancer aberrations are most likely to be functional genes or potential therapeutic targets. Here, we found a total of 137 genes were ectopically expressed in eight cancer types, of which Holliday junction recognition protein (HJURP) was significantly upregulated in prostate cancer (PCa). Moreover, patients with higher HJURP mRNA and protein levels had poorer outcomes, and the protein levels served as an independent prognosis factor for the overall survival of PCa patients. Functionally, ectopic HJURP expression promoted PCa cells proliferation in vitro and in vivo. Mechanistically, HJURP increased the ubiquitination of cyclin-dependent kinase inhibitor 1 (CDKN1A) via the GSK3β/JNK signaling pathway and decreased its stability. This study investigated the role of HJURP in PCa proliferation and may provide a novel prognostic and therapeutic target for PCa.

Cell senescence in neuropathology: A focus on neurodegeneration and tumours

The study of cell senescence is a burgeoning field. Senescent cells can modify the cellular microenvironment through the secretion of a plethora of biologically active products referred to as the senescence-associated secretory phenotype (SASP). The consequences of these paracrine signals can be either beneficial for tissue homeostasis, if senescent cells are properly cleared and SASP activation is transient, or result in organ dysfunction, when senescent cells accumulate within the tissues and SASP activation is persistent. Several studies have provided evidence for the role of senescence and SASP in promoting age-related diseases or driving organismal ageing. The hype about senescence has been further amplified by the fact that a group of drugs, named senolytics, have been used to successfully ameliorate the burden of age-related diseases and increase health and life span in mice. Ablation of senescent cells in the brain prevents disease progression and improves cognition in murine models of neurodegenerative conditions. The role of senescence in cancer has been more thoroughly investigated, and it is now accepted that senescence is a double-edged sword that can paradoxically prevent or promote tumourigenesis in a context-dependent manner. In addition, senescence induction followed by senolytic treatment is starting to emerge as a novel therapeutic avenue that could improve current anti-cancer therapies and reduce tumour recurrence. In this review, we discuss recent findings supporting the role of cell senescence in the pathogenesis of neurodegenerative diseases and in brain tumours. A better understanding of senescence is likely to result in the development of novel and efficacious anti-senescence therapies against these brain pathologies.

The Links between Parkinson's Disease and Cancer

Epidemiologic studies indicate a decreased incidence of most cancer types in Parkinson’s disease (PD) patients. However, some neoplasms are associated with a higher risk of occurrence in PD patients. Both pathologies share some common biological pathways. Although the etiologies of PD and cancer are multifactorial, some factors associated with PD, such as α-synuclein aggregation; mutations of PINK1, PARKIN, and DJ-1; mitochondrial dysfunction; and oxidative stress can also be involved in cancer proliferation or cancer suppression. The main protein associated with PD, i.e., α-synuclein, can be involved in some types of neoplastic formations. On the other hand, however, its downregulation has been found in the other cancers. PINK1 can act as oncogenic or a tumor suppressor. PARKIN dysfunction may lead to some cancers’ growth, and its expression may be associated with some tumors’ suppression. DJ-1 mutation is involved in PD pathogenesis, but its increased expression was found in some neoplasms, such as melanoma or breast, lung, colorectal, uterine, hepatocellular, and nasopharyngeal cancers. Both mitochondrial dysfunction and oxidative stress are involved in PD and cancer development. The aim of this review is to summarize the possible associations between PD and carcinogenesis.

Upregulation of Parkin Accelerates Osteoblastic Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells and Bone Regeneration by Enhancing Autophagy and β-Catenin Signaling

Osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) plays a key role in bone formation. Parkin, an E3 ubiquitin ligase, related to Parkinson’s disease and aging. Previous studies have indicated that Parkinson’s disease have a higher risk of osteoporotic fracture. To investigate the effects and underlying mechanism of Parkin in the osteogenic differentiation of BMSCs, osteogenic differentiation was analyzed following upregulation or downregulation of Parkin. We found that Parkin was increased during differentiation. Parkin overexpression enhanced osteo-specific markers, and downregulation of Parkin mitigated osteo-specific markers. Moreover, upregulation of Parkin promoted β-catenin expression and autophagy and vice versa. The upregulation of β-catenin enhanced autophagy, and the activation of autophagy also increased the expression of β-catenin in Parkin-downregulated BMSCs. Parkin-overexpressed cell sheets accelerated bone healing in a tibial fracture model. Based on these results, we concluded that Parkin meditates osteoblastic differentiation of BMSCs via β-catenin and autophagy signaling.

PARK2 promotes mitochondrial pathway of apoptosis and antimicrotubule drugs chemosensitivity via degradation of phospho-BCL-2

Rationale: Neoadjuvant chemotherapy has become the standard treatment of locally advanced breast cancer. Antimicrotubule drugs and DNA-damaging drugs are the most popular medicines used for neoadjuvant chemotherapy. However, we are unable to predict which chemotherapeutic drug will benefit to an individual patient. PARK2 as a tumor suppressor in breast cancer has been reported. While the role of PARK2 in chemotherapy response remains unknown. In this study, we explore the impact of PARK2 on chemosensitivity in breast cancer. Methods: PARK2 expression in breast cancer patients with different neoadjuvant chemotherapeutic regimens was studied using immunohistochemistry. Data was correlated to disease-free survival (DFS), overall survival and pathologic complete response (pCR). The functional roles of PARK2 were demonstrated by a series of in vitro and in vivo experiments. Including mass spectrometry, Co-immunoprecipitation, isolation of subcellular fractionation, fluorescence microscopy, in vivo ubiquitination assay and luciferase analyses. Results: Highly expressed PARK2 predicted better response to antimicrotubule drugs-containing regimen associated with higher rate of pathologic complete response (pCR). In contrast, PARK2 expression did not predict response to the DNA-damaging drugs regimen. Following antimicrotubule drugs treatment, levels of PARK2 was upregulated due to the repression of STAT3-mediated transcriptional inhibition of PARK2. Moreover, overexpression of PARK2 specifically rendered cells more sensitive to antimicrotubule drugs, but not to DNA-damaging drugs. Depletion of PARK2 enhanced resistance to antimicrotubule drugs. Mechanistically, PARK2 markedly activated the mitochondrial pathway of apoptosis after exposure to antimicrotubule drugs. This occurred through downregulating the antiapoptotic protein, phospho-BCL-2. BCL-2 phosphorylation can be specifically induced by antimicrotubule drugs, whereas DNA-damaging drugs do not. Notably, PARK2 interacted with phospho-BCL-2 (Ser70) and promoted ubiquitination of BCL-2 in an E3 ligase-dependent manner. Hence, PARK2 significantly enhanced the chemosensitivity of antimicrotubule drugs both in vitro and in vivo, while loss-of-function PARK2 mutants did not. Conclusions: Our findings explained why PARK2 selectively confers chemosensitivity to antimicrotubule drugs, but not to DNA-damaging drugs. In addition, we identified PARK2 as a novel mediator of antimicrotubule drugs sensitivity, which can predict response of breast cancer patients to antimicrotubule drugs-containing regime.

Parkin mutation decreases neurite complexity and maturation in neurons derived from human fibroblasts

BACKGROUND

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, and mainly characterized by the progressive degeneration of dopaminergic (DA) neurons in the midbrain substantia nigra and non-DA neurons in many other parts of the brain. Previous studies have shown that several genes associated with the causes of PD can influence neurite outgrowth. Mutations of PRKN (encoding parkin, an E3 ubiquitin ligase) are the most frequent cause of recessively inherited PD. The lack of a PD phenotype in Prkn-knockout mice may imply a unique vulnerability of neurons to parkin mutations.

METHODS

CRISPR/Cas9 technology was used to target random mutations into exon3 of PRKN in human fibroblasts cell line MRC-5. The induced DA neurons were achieved from direct conversion of fibroblasts (with or without PRKN mutations) via a cocktail of transcriptional factors (Ascl1, Nurr1, Lmx1a, miRNA124, p53 shRNA) and chemicals (CHIR99021, Purmorphamine, TGFβ3, BDNF, GDNF, NGF and Y27632).

RESULTS

Herein, we successfully established human neuronal cell models with parkin mutations from fibroblast-reprogrammed neurons. In these neurons, not only were the induced ratio and number of mature neurons markedly decreased, but also the complexity of the neuronal processes, measured by total neurite length and number of terminals, was greatly reduced, in TH⁺ and TH^-neurons with PRKN mutations.

CONCLUSIONS

The results suggest that parkin not only maintains the morphological complexity of human neurons, but also influences maturation and differentiation in the fibroblast reprogramming process.

Perioperative Heart-Brain Axis Protection in Obese Surgical Patients: The Nutrigenomic Approach

The number of obese patients undergoing cardiac and noncardiac surgery is rapidly increasing because they are more prone to concomitant diseases, such as diabetes, thrombosis, sleep-disordered breathing, cardiovascular and cerebrovascular disorders. Even if guidelines are already available to manage anesthesia and surgery of obese patients, the assessment of the perioperative morbidity and mortality from heart and brain disorders in morbidly obese surgical patients will be challenging in the next years. The present review will recapitulate the new mechanisms underlying the Heart-brain Axis (HBA) vulnerability during the perioperative period in healthy and morbidly obese patients. Finally, we will describe the nutrigenomics approach, an emerging noninvasive dietary tool, to maintain a healthy body weight and to minimize the HBA propensity to injury in obese individuals undergoing all types of surgery by personalized intake of plant compounds that may regulate the switch from health to disease in an epigenetic manner. Our review provides current insights into the mechanisms underlying HBA response in obese surgical patients and how they are modulated by epigenetically active food constituents.

The mitochondria-targeted anti-oxidant MitoQ protects against intervertebral disc degeneration by ameliorating mitochondrial dysfunction and redox imbalance

Objective

Mitochondrial dysfunction, oxidative stress and nucleus pulposus (NP) cell apoptosis are important contributors to the development and pathogenesis of intervertebral disc degeneration (IDD). Here, we comprehensively evaluated the effects of mitochondrial dynamics, mitophagic flux and Nrf2 signalling on the mitochondrial quality control, ROS production and NP cell survival in in vitro and ex vivo compression models of IDD and explored the effects of the mitochondria‐targeted anti‐oxidant MitoQ and its mechanism.

Material and methods

Human NP cells were exposed to mechanical compression to mimic pathological conditions.

Results

Compression promoted oxidative stress, mitochondrial dysfunction and NP cell apoptosis. Mechanistically, compression disrupted the mitochondrial fission/fusion balance, inducing fatal fission. Concomitantly, PINK1/Parkin‐mediated mitophagy was activated, whereas mitophagic flux was blocked. Nrf2 anti‐oxidant pathway was insufficiently activated. These caused the damaged mitochondria accumulation and persistent oxidative damage. Moreover, MitoQ restored the mitochondrial dynamics balance, alleviated the impairment of mitophagosome‐lysosome fusion and lysosomal function and enhanced the Nrf2 activity. Consequently, damaged mitochondria were eliminated, redox balance was improved, and cell survival increased. Additionally, MitoQ alleviated IDD in an ex vivo rat compression model.

Conclusions

These findings suggest that comodulation of mitochondrial dynamics, mitophagic flux and Nrf2 signalling alleviates sustained mitochondrial dysfunction and oxidative stress and represents a promising therapeutic strategy for IDD; furthermore, our results provide evidence that MitoQ might serve as an effective therapeutic agent for this disorder.

Loss of SATB1 Induces p21-Dependent Cellular Senescence in Post-mitotic Dopaminergic Neurons

Cellular senescence is a mechanism used by mitotic cells to prevent uncontrolled cell division. As senescent cells persist in tissues, they cause local inflammation and are harmful to surrounding cells, contributing to aging. Generally, neurodegenerative diseases, such as Parkinson's, are disorders of aging. The contribution of cellular senescence to neurodegeneration is still unclear. SATB1 is a DNA binding protein associated with Parkinson's disease. We report that SATB1 prevents cellular senescence in post-mitotic dopaminergic neurons. Loss of SATB1 causes activation of a cellular senescence transcriptional program in dopamine neurons both in human stem cell-derived dopaminergic neurons and in mice. We observed phenotypes that are central to cellular senescence in SATB1 knockout dopamine neurons in vitro and in vivo. Moreover, we found that SATB1 directly represses expression of the pro-senescence factor p21 in dopaminergic neurons. Our data implicate senescence of dopamine neurons as a contributing factor in the pathology of Parkinson's disease.

Loss of parkin reduces lung tumor development by blocking p21 degradation

Several epidemiological studies have demonstrated the reciprocal relationship between the development of cancer and Parkinson’s disease (PD). However, the possible mechanisms underlying this relationship remain unclear. To identify this relationship, we first compared lung tumor growth in parkin knockout (KO) mice and wild-type (WT) mice. Parkin KO mice showed decreased lung tumor growth and increased expression of p21, a cell cycle arrester, as compared with WT mice. We also found that parkin interacts with p21, resulting in its degradation; however, parkin KO, knockdown, as well as mutation (R275W or G430D) reduced the degradation of p21. We investigated whether parkin KO increases the association of p21 with proliferating cell nuclear antigen (PCNA) or CDK2 by reducing p21 degradation, and, thus, arresting the cell cycle. The interaction between p21 and PCNA or CDK2 was also enhanced by parkin knockdown, and this increased interaction induced sub G0/G1 arrest, leading to cell death. Therefore, our data indicate that parkin KO reduces the development of lung tumors via cell cycle arrest by blocking the degradation of p21. These findings suggest that PD could be associated with lower lung cancer incidence.

Decreased Lung Tumor Development in SwAPP Mice through the Downregulation of CHI3L1 and STAT 3 Activity via the Upregulation of miRNA342-3p

We previously found that lung tumor development was reduced in a presenilin (PS) Alzheimer’s disease (AD) mouse model. Here, we investigated whether this reducing effect could occur in a different AD mouse model. We investigated urethane-induced (1 mg/g) lung tumor development and melanoma growth in Swedish amyloid precursor protein (SwAPP) transgenic mice. The expression of chitinase-3-like-1 (Chi3L1) increased during lung tumor development and melanoma growth, which was accompanied by an increase in the activity of signal transducer and activator of transcription 3 (STAT3) and the downregulation of miRNA342-3p in wild-type mice. Like tumor development, the expression of Chi3L1 and STAT3 activity was reduced in the SwAPP mice, whereas the expression of miRNA342-3p was upregulated. In addition, Chi3L1 knockdown in the lung cancer and melanoma tissues reduced cancer cell growth and STAT3 activity but enhanced miRNA342-3p expression. However, the miRNA342-3p mimic decreased Chi3L1 expression, cancer cell growth, and STAT3 activity. Moreover, a STAT3 inhibitor reduced Chi3L1 expression and cancer cell growth but enhanced miRNA342-3p expression. These data showed that lung tumor development was reduced through the decrease of Chi3L1 expression via the STAT3-dependent upregulation of miRNA342-3p. This study indicates that lung tumor development could be reduced in SwAPP AD mice.

Applications of Gene Editing in Chickens: A New Era Is on the Horizon

The chicken represents a valuable model for research in the area of immunology, infectious diseases as well as developmental biology. Although it was the first livestock species to have its genome sequenced, there was no reverse genetic technology available to help understanding specific gene functions. Recently, homologous recombination was used to knockout the chicken immunoglobulin genes. Subsequent studies using immunoglobulin knockout birds helped to understand different aspects related to B cell development and antibody production. Furthermore, the latest advances in the field of genome editing including the CRISPR/Cas9 system allowed the introduction of site specific gene modifications in various animal species. Thus, it may provide a powerful tool for the generation of genetically modified chickens carrying resistance for certain pathogens. This was previously demonstrated by targeting the Trp38 region which was shown to be effective in the control of avian leukosis virus in chicken DF-1 cells. Herein we review the current and future prospects of gene editing and how it possibly contributes to the development of resistant chickens against infectious diseases.

SNAP23 suppresses cervical cancer progression via modulating the cell cycle

OBJECTIVE

Cervical cancer (CC) is one of the most common gynecologic tumors in women worldwide, with poor prognosis and low survival rate. In this study, we identified SNAP23 as a potential tumor suppressor gene in CC.

METHODS

The expression of SNAP23 in tissues and cell lines were measured by qRT-PCR, western blot and IHC. Knockdown of SNAP23 by siRNA and ectopic expression of SNAP23 by overexpression plasmid were performed to observe the biological function of SNAP23 in CC. Xenograft nude mice models were established to measure its function in vivo.

RESULTS

SNAP23 was downregulated in CC tissues and had a negative correlation with advanced clinical characteristics. Ectopic expression of SNAP23 suppressed malignant phonotype of CC while knockdown of SNAP23 promoted the progression of CC in vitro. The flow cytometry analysis revealed that SNAP23 exerted its tumor suppressor activity via inducing G2/M cell cycle arrest. Moreover, xenograft tumor models showed that SNAP23 suppresses tumor growth in vivo.

CONCLUSIONS

Our results revealed that SNAP23 suppressed progression of CC and induced cell cycle G2/M arrest via upregulating p21^cip1 and downregulating CyclinB1.