Primary cilia mediate mitochondrial stress responses to promote dopamine neuron survival in a Parkinson’s disease model

AbstractA primary cilium is an antenna-like structure on the cell surface that plays a crucial role in sensory perception and signal transduction. Mitochondria, the ‘powerhouse’ of the cell, control cell survival, and death. The cellular ability to remove dysfunctional mitochondria through mitophagy is important for cell survival. We show here that mitochondrial stress, caused by respiratory complex inhibitors and excessive fission, robustly stimulates ciliogenesis in different types of cells including neuronal cells. Mitochondrial stress-induced ciliogenesis is mediated by mitochondrial reactive oxygen species generation, subsequent activation of AMP-activated protein kinase and autophagy. Conversely, abrogation of ciliogenesis compromises mitochondrial stress-induced autophagy, leading to enhanced cell death. In mice, treatment with mitochondrial toxin, MPTP elicits ciliary elongation and autophagy in the substantia nigra dopamine neurons. Blockade of cilia formation in these neurons attenuates MPTP-induced autophagy but facilitates dopamine neuronal loss and motor disability. Our findings demonstrate the important role of primary cilia in cellular pro-survival responses during mitochondrial stress.

Download Full-text

Primary cilia mediate mitochondrial stress responses and autophagy to promote cell survival in a Parkinson's disease model

IBRO Reports ◽

10.1016/j.ibror.2019.07.387 ◽

2019 ◽

Vol 6 ◽

pp. S121

Author(s):

Ji-Eun Bae ◽

Doo Sin Jo ◽

Na Yeon Park ◽

Jun Bum Kim ◽

Hyun Jun Park ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cell Survival ◽

Stress Responses ◽

Primary Cilia ◽

Disease Model ◽

Mitochondrial Stress ◽

Promote Cell Survival

Download Full-text

Faculty Opinions recommendation of Induction of functional dopamine neurons from human astrocytes in vitro and mouse astrocytes in a Parkinson's disease model.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727495722.793564376 ◽

2019 ◽

Author(s):

Oliver Brüstle

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Disease Model ◽

Dopamine Neurons ◽

Human Astrocytes

Download Full-text

Crosstalk between endoplasmic reticulum stress and oxidative stress: a dynamic duo in multiple myeloma

Cellular and Molecular Life Sciences ◽

10.1007/s00018-021-03756-3 ◽

2021 ◽

Author(s):

Sinan Xiong ◽

Wee-Joo Chng ◽

Jianbiao Zhou

Keyword(s):

Oxidative Stress ◽

Multiple Myeloma ◽

Endoplasmic Reticulum ◽

Er Stress ◽

Cell Fate ◽

Stress Responses ◽

Plasma Cells ◽

Reactive Oxygen Species Generation ◽

Future Research ◽

And Oxidative Stress

AbstractUnder physiological and pathological conditions, cells activate the unfolded protein response (UPR) to deal with the accumulation of unfolded or misfolded proteins in the endoplasmic reticulum. Multiple myeloma (MM) is a hematological malignancy arising from immunoglobulin-secreting plasma cells. MM cells are subject to continual ER stress and highly dependent on the UPR signaling activation due to overproduction of paraproteins. Mounting evidence suggests the close linkage between ER stress and oxidative stress, demonstrated by overlapping signaling pathways and inter-organelle communication pivotal to cell fate decision. Imbalance of intracellular homeostasis can lead to deranged control of cellular functions and engage apoptosis due to mutual activation between ER stress and reactive oxygen species generation through a self-perpetuating cycle. Here, we present accumulating evidence showing the interactive roles of redox homeostasis and proteostasis in MM pathogenesis and drug resistance, which would be helpful in elucidating the still underdefined molecular pathways linking ER stress and oxidative stress in MM. Lastly, we highlight future research directions in the development of anti-myeloma therapy, focusing particularly on targeting redox signaling and ER stress responses.

Download Full-text

LONP1 and ClpP cooperatively regulate mitochondrial proteostasis for cancer cell survival

Oncogenesis ◽

10.1038/s41389-021-00306-1 ◽

2021 ◽

Vol 10 (2) ◽

Author(s):

Yu Geon Lee ◽

Hui Won Kim ◽

Yeji Nam ◽

Kyeong Jin Shin ◽

Yu Jin Lee ◽

...

Keyword(s):

Cell Death ◽

Cell Growth ◽

Cell Survival ◽

Cancer Cell ◽

Stress Responses ◽

Molecular Mechanisms ◽

Tca Cycle ◽

Mitochondrial Matrix ◽

Mitochondrial Functions ◽

Cancer Cell Survival

AbstractMitochondrial proteases are key components in mitochondrial stress responses that maintain proteostasis and mitochondrial integrity in harsh environmental conditions, which leads to the acquisition of aggressive phenotypes, including chemoresistance and metastasis. However, the molecular mechanisms and exact role of mitochondrial proteases in cancer remain largely unexplored. Here, we identified functional crosstalk between LONP1 and ClpP, which are two mitochondrial matrix proteases that cooperate to attenuate proteotoxic stress and protect mitochondrial functions for cancer cell survival. LONP1 and ClpP genes closely localized on chromosome 19 and were co-expressed at high levels in most human cancers. Depletion of both genes synergistically attenuated cancer cell growth and induced cell death due to impaired mitochondrial functions and increased oxidative stress. Using mitochondrial matrix proteomic analysis with an engineered peroxidase (APEX)-mediated proximity biotinylation method, we identified the specific target substrates of these proteases, which were crucial components of mitochondrial functions, including oxidative phosphorylation, the TCA cycle, and amino acid and lipid metabolism. Furthermore, we found that LONP1 and ClpP shared many substrates, including serine hydroxymethyltransferase 2 (SHMT2). Inhibition of both LONP1 and ClpP additively increased the amount of unfolded SHMT2 protein and enhanced sensitivity to SHMT2 inhibitor, resulting in significantly reduced cell growth and increased cell death under metabolic stress. Additionally, prostate cancer patients with higher LONP1 and ClpP expression exhibited poorer survival. These results suggest that interventions targeting the mitochondrial proteostasis network via LONP1 and ClpP could be potential therapeutic strategies for cancer.

Download Full-text

Therapeutics potentiating microglial p21-Nrf2 axis can rescue neurodegeneration caused by neuroinflammation

Science Advances ◽

10.1126/sciadv.abc1428 ◽

2020 ◽

Vol 6 (46) ◽

pp. eabc1428

Author(s):

A. Nakano-Kobayashi ◽

A. Fukumoto ◽

A. Morizane ◽

D. T. Nguyen ◽

T. M. Le ◽

...

Keyword(s):

Neurodegenerative Disorders ◽

Inflammatory Responses ◽

Therapeutic Potential ◽

Neuronal Survival ◽

Disease Model ◽

Neuronal Loss ◽

Induced Pluripotent Stem Cell ◽

Related Factor ◽

Induced Pluripotent ◽

Novel Therapeutic

Neurodegenerative disorders are caused by progressive neuronal loss, and there is no complete treatment available yet. Neuroinflammation is a common feature across neurodegenerative disorders and implicated in the progression of neurodegeneration. Dysregulated activation of microglia causes neuroinflammation and has been highlighted as a treatment target in therapeutic strategies. Here, we identified novel therapeutic candidate ALGERNON2 (altered generation of neurons 2) and demonstrate that ALGERNON2 suppressed the production of proinflammatory cytokines and rescued neurodegeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)–induced Parkinson’s disease model. ALGERNON2 stabilized cyclinD1/p21 complex, leading to up-regulation of nuclear factor erythroid 2–related factor 2 (Nrf2), which contributes to antioxidative and anti-inflammatory responses. Notably, ALGERNON2 enhanced neuronal survival in other neuroinflammatory conditions such as the transplantation of induced pluripotent stem cell–derived dopaminergic neurons into murine brains. In conclusion, we present that the microglial potentiation of the p21-Nrf2 pathway can contribute to neuronal survival and provide novel therapeutic potential for neuroinflammation-triggered neurodegeneration.

Download Full-text

Restoration of Noradrenergic Function in Parkinson’s Disease Model Mice

ASN NEURO ◽

10.1177/17590914211009730 ◽

2021 ◽

Vol 13 ◽

pp. 175909142110097

Author(s):

Kui Cui ◽

Fan Yang ◽

Turan Tufan ◽

Muhammad U. Raza ◽

Yanqiang Zhan ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Transcription Factors ◽

Disease Model ◽

Neuronal Loss ◽

Mrna Levels ◽

Gene Therapies ◽

Protein Levels ◽

Dopaminergic Systems ◽

And Function

Dysfunction of the central noradrenergic and dopaminergic systems is the primary neurobiological characteristic of Parkinson’s disease (PD). Importantly, neuronal loss in the locus coeruleus (LC) that occurs in early stages of PD may accelerate progressive loss of dopaminergic neurons. Therefore, restoring the activity and function of the deficient noradrenergic system may be an important therapeutic strategy for early PD. In the present study, the lentiviral constructions of transcription factors Phox2a/2b, Hand2 and Gata3, either alone or in combination, were microinjected into the LC region of the PD model VMAT2 Lo mice at 12 and 18 month age. Biochemical analysis showed that microinjection of lentiviral expression cassettes into the LC significantly increased mRNA levels of Phox2a, and Phox2b, which were accompanied by parallel increases of mRNA and proteins of dopamine β-hydroxylase (DBH) and tyrosine hydroxylase (TH) in the LC. Furthermore, there was considerable enhancement of DBH protein levels in the frontal cortex and hippocampus, as well as enhanced TH protein levels in the striatum and substantia nigra. Moreover, these manipulations profoundly increased norepinephrine and dopamine concentrations in the striatum, which was followed by a remarkable improvement of the spatial memory and locomotor behavior. These results reveal that over-expression of these transcription factors in the LC improves noradrenergic and dopaminergic activities and functions in this rodent model of PD. It provides the necessary groundwork for the development of gene therapies of PD, and expands our understanding of the link between the LC-norepinephrine and dopamine systems during the progression of PD.

Download Full-text

RAE-1 ligands for the NKG2D receptor are regulated by E2F transcription factors, which control cell cycle entry

Journal of Experimental Medicine ◽

10.1084/jem.20120565 ◽

2012 ◽

Vol 209 (13) ◽

pp. 2409-2422 ◽

Cited By ~ 77

Author(s):

Heiyoun Jung ◽

Benjamin Hsiung ◽

Kathleen Pestal ◽

Emily Procyk ◽

David H. Raulet

Keyword(s):

Cell Cycle ◽

Transcription Factors ◽

Stress Responses ◽

Transcriptional Activation ◽

Posttranscriptional Regulation ◽

Cellular Proliferation ◽

Control Cell ◽

T Cell Subsets ◽

Cell Cycle Entry

The NKG2D stimulatory receptor expressed by natural killer cells and T cell subsets recognizes cell surface ligands that are induced on transformed and infected cells and facilitate immune rejection of tumor cells. We demonstrate that expression of retinoic acid early inducible gene 1 (RAE-1) family NKG2D ligands in cancer cell lines and proliferating normal cells is coupled directly to cell cycle regulation. Raet1 genes are directly transcriptionally activated by E2F family transcription factors, which play a central role in regulating cell cycle entry. Induction of RAE-1 occurred in primary cell cultures, embryonic brain cells in vivo, and cells in healing skin wounds and, accordingly, wound healing was delayed in mice lacking NKG2D. Transcriptional activation by E2Fs is likely coordinated with posttranscriptional regulation by other stress responses. These findings suggest that cellular proliferation, as occurs in cancer cells but also other pathological conditions, is a key signal tied to immune reactions mediated by NKG2D-bearing lymphocytes.

Download Full-text