Small molecule-mediated up-regulation of microRNA targeting a key cell death modulator BNIP3 improves cardiac function following ischemic injury

Abstract Genetic ablation of BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), an essential regulator of cardiac cell death, is an effective way to prevent cardiac cell death triggered by pathologic conditions. However, currently there exists no known means, such as inhibitors, to down-regulate BNIP3 in mature heart. Here, we report that a small molecule inducer of microRNA-182 (miR-182) suppressed ischemia/reperfusion (I/R)-induced cardiac cell death by down-regulating BNIP3. We first selected miR-182 as a potent BNIP3-targeting miRNA based on miRNA-target prediction databases and empirical data. The subsequent screening of small molecules for inducing miR-182 expression identified Kenpaullone as a hit compound. Both exogenous miR-182 and Kenpaullone significantly suppressed hypoxia-induced cardiomyocyte death in vitro. To investigate the effect of changing substituents of Kenpaullone on miR-182 expression, we synthesized 9 derivatives of Kenpaullone. Among these derivatives, compound 5 showed significantly improved ability to induce miR-182 expression. The results of the in vivo study showed that compound 5 significantly improved heart function following I/R-injury in rats. Our study provides strong evidence that the small molecule-mediated up-regulation of miRNAs is a viable strategy to down-regulate target proteins with no known chemical inhibitor and that compound 5 may have potential to prevent I/R-inflicted cardiac cell death.

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Expression and subcellular localization of BNIP3 in hypoxic hepatocytes and liver stress

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.90526.2008 ◽

2009 ◽

Vol 296 (3) ◽

pp. G499-G509 ◽

Cited By ~ 21

Author(s):

Mallikarjuna R. Metukuri ◽

Donna Beer-Stolz ◽

Rajaie A. Namas ◽

Rajeev Dhupar ◽

Andres Torres ◽

...

Keyword(s):

Cell Death ◽

Western Blot ◽

Blot Analysis ◽

Western Blot Analysis ◽

Ischemia Reperfusion ◽

Redox Stress ◽

No Donor ◽

Interacting Protein

We have previously demonstrated that the Bcl-2/adenovirus EIB 19-kDa interacting protein 3 (BNIP3), a cell death-related member of the Bcl-2 family, is upregulated in vitro and in vivo in both experimental and clinical settings of redox stress and that nitric oxide (NO) downregulates its expression. In this study we sought to examine the expression and localization of BNIP3 in murine hepatocytes and in a murine model of hemorrhagic shock (HS) and ischemia-reperfusion (I/R). Freshly isolated mouse hepatocytes were exposed to 1% hypoxia for 6 h followed by reoxygenation for 18 h, and protein was isolated for Western blot analysis. Hepatocytes grown on coverslips were fixed for localization studies. Similarly, livers from surgically cannulated C57Bl/6 mice and from mice cannulated and subjected to 1–4 h of HS were processed for protein isolation and Western blot analysis. In hepatocytes, BNIP3 was expressed constitutively but was upregulated under hypoxic conditions, and this upregulation was countered by treatment with a NO donor. Surprisingly, BNIP3 was localized in the nucleus of normoxic hepatocytes, in the cytoplasm following hypoxia, and again in the nucleus following reoxygenation. Upregulation of BNIP3 partially required p38 MAPK activation. BNIP3 contributed to hypoxic injury in hepatocytes, since this injury was diminished by knockdown of BNIP3 mRNA. Hepatic BNIP3 was also upregulated in two different models of liver stress in vivo, suggesting that a multitude of inflammatory stresses can lead to the modulation of BNIP3. In turn, the upregulation of BNIP3 appears to be one mechanism of hepatocyte cell death and liver damage in these settings.

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iPLA2β Contributes to ER Stress-Induced Apoptosis during Myocardial Ischemia/Reperfusion Injury

Cells ◽

10.3390/cells10061446 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1446

Author(s):

Tingting Jin ◽

Jun Lin ◽

Yingchao Gong ◽

Xukun Bi ◽

Shasha Hu ◽

...

Keyword(s):

Cell Death ◽

Heart Disease ◽

Myocardial Ischemia ◽

Ischemic Heart Disease ◽

Er Stress ◽

Ischemia Reperfusion ◽

Myocardial Ischemia Reperfusion ◽

Induced Apoptosis

Both calcium-independent phospholipase A2 beta (iPLA2β) and endoplasmic reticulum (ER) stress regulate important pathophysiological processes including inflammation, calcium homeostasis and apoptosis. However, their roles in ischemic heart disease are poorly understood. Here, we show that the expression of iPLA2β is increased during myocardial ischemia/reperfusion (I/R) injury, concomitant with the induction of ER stress and the upregulation of cell death. We further show that the levels of iPLA2β in serum collected from acute myocardial infarction (AMI) patients and in samples collected from both in vivo and in vitro I/R injury models are significantly elevated. Further, iPLA2β knockout mice and siRNA mediated iPLA2β knockdown are employed to evaluate the ER stress and cell apoptosis during I/R injury. Additionally, cell surface protein biotinylation and immunofluorescence assays are used to trace and locate iPLA2β. Our data demonstrate the increase of iPLA2β augments ER stress and enhances cardiomyocyte apoptosis during I/R injury in vitro and in vivo. Inhibition of iPLA2β ameliorates ER stress and decreases cell death. Mechanistically, iPLA2β promotes ER stress and apoptosis by translocating to ER upon myocardial I/R injury. Together, our study suggests iPLA2β contributes to ER stress-induced apoptosis during myocardial I/R injury, which may serve as a potential therapeutic target against ischemic heart disease.

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miR-182-5p and miR-378a-3p regulate ferroptosis in I/R-induced renal injury

Cell Death and Disease ◽

10.1038/s41419-020-03135-z ◽

2020 ◽

Vol 11 (10) ◽

Author(s):

Chenguang Ding ◽

Xiaoming Ding ◽

Jin Zheng ◽

Bo Wang ◽

Yang Li ◽

...

Keyword(s):

Cell Death ◽

Renal Injury ◽

Molecular Mechanisms ◽

Ischemia Reperfusion ◽

Kidney Injury ◽

Luciferase Reporter ◽

Renal Tubular Cell ◽

In Cells

Abstract Renal tubular cell death is the key factor of the pathogenesis of ischemia/reperfusion (I/R) kidney injury. Ferroptosis is a type of regulated cell death (RCD) found in various diseases. However, the underlying molecular mechanisms related to ferroptosis in renal I/R injury remain unclear. In the present study, we investigated the regulatory role of microRNAs on ferroptosis in I/R-induced renal injury. We established the I/R-induced renal injury model in rats, and H/R induced HK-2 cells injury in vitro. CCK-8 was used to measure cell viability. Fe2+ and ROS levels were assayed to evaluate the activation of ferroptosis. We performed RNA sequencing to profile the miRNAs expression in H/R-induced injury and ferroptosis. Western blot analysis was used to detect the protein expression. qRT-PCR was used to detect the mRNA and miRNA levels in cells and tissues. We further used luciferase reporter assay to verify the direct targeting effect of miRNA. We found that ischemia/reperfusion-induced ferroptosis in rat’s kidney. We identified that miR-182-5p and miR-378a-3p were upregulated in the ferroptosis and H/R-induced injury, and correlates reversely with glutathione peroxidases 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression in renal I/R injury tissues, respectively. In vitro studies showed that miR-182-5p and miR-378a-3p induced ferroptosis in cells. We further found that miR-182-5p and miR-378a-3p regulated the expression of GPX4 and SLC7A11 negatively by directly binding to the 3′UTR of GPX4 and SLC7A11 mRNA. In vivo study showed that silencing miR-182-5p and miR-378a-3p alleviated the I/R-induced renal injury in rats. In conclusion, we demonstrated that I/R induced upregulation of miR-182-5p and miR-378a-3p, leading to activation of ferroptosis in renal injury through downregulation of GPX4 and SLC7A11.

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Therapeutic Inhibition of Acid Sensing Ion Channel 1a Recovers Heart Function After Ischemia-Reperfusion Injury

Circulation ◽

10.1161/circulationaha.121.054360 ◽

2021 ◽

Author(s):

Meredith A. Redd ◽

Sarah E. Scheuer ◽

Natalie J. Saez ◽

Yusuke Yoshikawa ◽

Han Sheng Chiu ◽

...

Keyword(s):

Ion Channel ◽

Reperfusion Injury ◽

Electromechanical Coupling ◽

Ischemia Reperfusion Injury ◽

Ex Vivo ◽

Heart Function ◽

Ischemia Reperfusion ◽

Genetic Ablation ◽

Organ Level

Background: Ischemia-reperfusion injury (IRI) is one of the major risk factors implicated in morbidity and mortality associated with cardiovascular disease. During cardiac ischemia, the build-up of acidic metabolites results in decreased intracellular and extracellular pH that can reach as low as 6.0-6.5. The resulting tissue acidosis exacerbates ischemic injury and significantly impacts cardiac function. Methods: We used genetic and pharmacological methods to investigate the role of acid sensing ion channel 1a (ASIC1a) in cardiac IRI at the cellular and whole organ level. Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) as well as ex vivo and in vivo models of IRI were used to test the efficacy of ASIC1a inhibitors as pre- and post-conditioning therapeutic agents. Results: Analysis of human complex trait genetics indicate that variants in the ASIC1 genetic locus are significantly associated with cardiac and cerebrovascular ischemic injuries. Using hiPSC-CMs in vitro and murine ex vivo heart models, we demonstrate that genetic ablation of ASIC1a improves cardiomyocyte viability after acute IRI. Therapeutic blockade of ASIC1a using specific and potent pharmacological inhibitors recapitulates this cardioprotective effect. We used an in vivo model of myocardial infarction (MI) and two models of ex vivo donor heart procurement and storage as clinical models to show that ASIC1a inhibition improves post-IRI cardiac viability. Use of ASIC1a inhibitors as pre- or post-conditioning agents provided equivalent cardioprotection to benchmark drugs, including the sodium-hydrogen exchange inhibitor zoniporide. At the cellular and whole organ level, we show that acute exposure to ASIC1a inhibitors has no impact on cardiac ion channels regulating baseline electromechanical coupling and physiological performance. Conclusions: Collectively, our data provide compelling evidence for a novel pharmacological strategy involving ASIC1a blockade as a cardioprotective therapy to improve the viability of hearts subjected to IRI.

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Assessing the Efficacy of Dietary Selenomethionine Supplementation in the Setting of Cardiac Ischemia/Reperfusion Injury

Antioxidants ◽

10.3390/antiox8110546 ◽

2019 ◽

Vol 8 (11) ◽

pp. 546 ◽

Cited By ~ 2

Author(s):

Leila Reyes ◽

David P. Bishop ◽

Clare L. Hawkins ◽

Benjamin S. Rayner

Keyword(s):

Cardiac Myocyte ◽

Hypochlorous Acid ◽

Ischemia Reperfusion Injury ◽

Heart Function ◽

Ischemia Reperfusion ◽

Cytosolic Calcium ◽

Cardiac Ischemia ◽

Cellular Damage

Oxidative stress is a major hallmark of cardiac ischemia/reperfusion (I/R) injury. This partly arises from the presence of activated phagocytes releasing myeloperoxidase (MPO) and its production of hypochlorous acid (HOCl). The dietary supplement selenomethionine (SeMet) has been shown to bolster endogenous antioxidant processes as well as readily react with MPO-derived oxidants. The aim of this study was to assess whether supplementation with SeMet could modulate the extent of cellular damage observed in an in vitro cardiac myocyte model exposed to (patho)-physiological levels of HOCl and an in vivo rat model of cardiac I/R injury. Exposure of the H9c2 cardiac myoblast cell line to HOCl resulted in a dose-dependent increase in necrotic cell death, which could be prevented by SeMet supplementation and was attributed to SeMet preventing the HOCl-induced loss of mitochondrial inner trans-membrane potential, and the associated cytosolic calcium accumulation. This protection was credited primarily to the direct oxidant scavenging ability of SeMet, with a minor contribution arising from the ability of SeMet to bolster cardiac myoblast glutathione peroxidase (GPx) activity. In vivo, a significant increase in selenium levels in the plasma and heart tissue were seen in male Wistar rats fed a diet supplemented with 2 mg kg−1 SeMet compared to controls. However, SeMet-supplementation demonstrated only limited improvement in heart function and did not result in better heart remodelling following I/R injury. These data indicate that SeMet supplementation is of potential benefit within pathological settings where excessive HOCl is known to be generated but has limited efficacy as a therapeutic agent for the treatment of heart attack.

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Up-regulation of MicroRNA-21 Mediates Isoflurane-induced Protection of Cardiomyocytes

Anesthesiology ◽

10.1097/aln.0000000000000567 ◽

2015 ◽

Vol 122 (4) ◽

pp. 795-805 ◽

Cited By ~ 29

Author(s):

Jessica M. Olson ◽

Yasheng Yan ◽

Xiaowen Bai ◽

Zhi-Dong Ge ◽

Mingyu Liang ◽

...

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Messenger Rna ◽

Functional Role ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Cell Death Protein

Abstract Background: Anesthetic cardioprotection reduces myocardial infarct size after ischemia–reperfusion injury. Currently, the role of microRNA in this process remains unknown. MicroRNAs are short, noncoding nucleotide sequences that negatively regulate gene expression through degradation or suppression of messenger RNA. In this study, the authors uncovered the functional role of microRNA-21 (miR-21) up-regulation after anesthetic exposure. Methods: MicroRNA and messenger RNA expression changes were analyzed by quantitative real-time polymerase chain reaction in cardiomyocytes after exposure to isoflurane. Lactate dehydrogenase release assay and propidium iodide staining were conducted after inhibition of miR-21. miR-21 target expression was analyzed by Western blot. The functional role of miR-21 was confirmed in vivo in both wild-type and miR-21 knockout mice. Results: Isoflurane induces an acute up-regulation of miR-21 in both in vivo and in vitro rat models (n = 6, 247.8 ± 27.5% and 258.5 ± 9.0%), which mediates protection to cardiomyocytes through down-regulation of programmed cell death protein 4 messenger RNA (n = 3, 82.0 ± 4.9% of control group). This protective effect was confirmed by knockdown of miR-21 and programmed cell death protein 4 in vitro. In addition, the protective effect of isoflurane was abolished in miR-21 knockout mice in vivo, with no significant decrease in infarct size compared with nonexposed controls (n = 8, 62.3 ± 4.6% and 56.2 ± 3.2%). Conclusions: The authors demonstrate for the first time that isoflurane mediates protection of cardiomyocytes against oxidative stress via an miR-21/programmed cell death protein 4 pathway. These results reveal a novel mechanism by which the damage done by ischemia/reperfusion injury may be decreased.

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Glucocorticoid-Induced Osteocytic Cell Death in a Hypoxic Environment Is Associated with Necroptosis

BioChem ◽

10.3390/biochem1020009 ◽

2021 ◽

Vol 1 (2) ◽

pp. 98-106

Author(s):

Shusuke Ueda ◽

Toru Ichiseki ◽

Miyako Shimasaki ◽

Hiroaki Hirata ◽

Norio Kawahara ◽

...

Keyword(s):

Cell Death ◽

Western Blotting ◽

Immunofluorescent Staining ◽

Cell Necrosis ◽

Interacting Protein ◽

Hypoxia Group ◽

Femoral Head Osteonecrosis ◽

Stress Environment

Neither the underlying pathophysiology of nor prophylactic strategies for glucocorticoid-associated femoral head osteonecrosis have yet been established. In neurovascular and cardiac ischemic disorders, necroptosis has been reported as a new concept of cell death. Here we investigated the involvement of necroptosis in glucocorticoid-induced osteonecrosis in vitro, the putative cause of which is ischemia. Murine osteocytic cells (MLO-Y4) to which 1 µM dexamethasone (Dex) was added and were cultured in 1% O2 (hypoxia) are thought to resemble the in vivo environment in which glucocorticoid-induced osteonecrosis occurs (H-D stress environment). Using such cells cultured for 24 h (Dex(+)/hypoxia(+) group), immunofluorescent staining and Western blotting were performed with receptor-interacting protein (RIP) 1 and RIP3, which are necroptosis expression factors. In addition, the necroptosis inhibitor necrostatin-1 (Nec-1) was added to Dex(+)/hypoxia(+) and cultured for 12 h and 24 h. Then using an Apoptotic/Necrotic Cells Detection Kit the numbers of apoptotic and necrotic cells were counted and compared. In Dex(+)/hypoxia(+) group, expression of both RIP1 and RIP3 was found. Additionally, in Western blotting, the addition of Nec-1 attenuated their expression. A decrease in the number of cell deaths was also found following Nec-1 administration. Necroptosis has been implicated as a cause of death in osteocytic cell necrosis. Use of the necroptosis inhibitor, Nec-1, suggests a possible approach to preventing osteocytic cell necrosis even in an H-D stress environment when given within 12 h.

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Abstract 23: Disruption of TRAF2-TAK1-NF-κB Signaling Axis Triggers K-48 Linked Poly-Ubiquitylation of RIP1 and Necrotic Cell Death in Doxorubicin Cardiotoxicity

Circulation Research ◽

10.1161/res.117.suppl_1.23 ◽

2015 ◽

Vol 117 (suppl_1) ◽

Author(s):

Rimpy Dhingra ◽

Victoria Margulets ◽

Floribeth Aguilar ◽

Lorrie A. Kirshenbaum

Keyword(s):

Cell Death ◽

Cardiac Myocytes ◽

Cell Injury ◽

Ventricular Myocytes ◽

Necrotic Cell Death ◽

Ros Production ◽

Necrotic Cell ◽

Interacting Protein

The anthracycline doxorubicin (Dox) is a highly effective anti-tumour agent, however, its use is limited by its severe cardiotoxic effects that manifests as heart failure. The decline in cardiac performance induced by doxorubicin remains poorly defined. A critical survival role for the canonical IKKβ -mTOR-NF-κB signaling pathway has been demonstrated in ventricular myocytes. In this report, we demonstrate that, Dox impairs IKKβ-mTOR- NF-κB signaling in ventricular myocytes accompanied by mitochondrial perturbations including mPTP, loss of mitochondrial membrane potential and ROS production. IKKβ- NF-κB signaling involves TRAF 2 mediated ligation of K63- ubiquitin chains to RIP1 (Receptor Interacting Protein 1) which serves as scaffold for recruitment of ubiquitylated Tak1 complexes and phosphorylation-dependent activation of IKKβ -NF-kB signaling. Interestingly, ventricular myocytes treated with dox demonstrated reduction in expression levels of TRAF2 and TAK1, in vivo and in vitro. This was accompanied by a decline in K63- and concomitant increase in K-48 linked polyubiquitination on RIP1, impaired NF-kB activation and necrotic cell death of cardiac myocytes. Interestingly, inhibiting the kinase activity of RIP1 with Necrostatin-1, (Nec1) suppressed necrotic cell injury induced by dox but not NF-kB activation. Concordant with these findings was a marked increase in necrotic cell death in cardiac myocytes defective for IKKB signaling or MEF cells deficient for p65 treated with dox. Notably, mitochondrial perturbations, including PT-pore opening , ROS production, calcium uptake, LDH, Tn(T) and HMGB-1 release and necrotic cell injury induced by dox were completely abrogated by restoring NF-kB signaling in cardiac myocytes or Nec-1. Herein, we provide novel evidence that K-48 linked poly ubiquitylation of RIP1 provides a functional switch that impairs NF-kB activation and signals necrosis in cells treated with dox. Interventions that modulate NF-kB activity may prove beneficial in mitigating the cardiotoxic effects of dox.

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Small Molecule Inhibition of Cdc7, a Key Cell Cycle Regulator and Novel Therapeutic Target, Successfully Inhibits Leukemia Cell Growth in Vitro and in Vivo

Blood ◽

10.1182/blood.v112.11.2668.2668 ◽

2008 ◽

Vol 112 (11) ◽

pp. 2668-2668

Author(s):

Mark G. Frattini ◽

David Shum ◽

Kristen M O’Dwyer ◽

Renier J. Brentjens ◽

Ray Yeh ◽

...

Keyword(s):

Cell Cycle ◽

Cell Death ◽

Small Molecule ◽

Leukemia Cell ◽

Standard Cell ◽

Cdc7 Kinase ◽

Kinase Inhibitory Activity ◽

Novel Therapeutic

Abstract Cdc7 is a heterodimeric serine/threonine protein kinase that is a key regulator in the process of initiation of DNA replication and the G1 to S phase transition. Both the kinase and its known substrates are over-expressed in the majority of human cancers. As a result of the recent progress in the areas of pharmacogenetics and high throughput screening technology, identifying specific small molecule inhibitors of cell cycle regulated protein kinases has provided a means not only to study these signal transduction pathways but also to identify potential novel therapeutic agents. To this end, we have developed an assay for Cdc7 kinase inhibitory activity using a highthroughput screening (HTS) approach, screening over 250,000 natural and synthetic small molecules. As a result, we have identified and confirmed seventeen compounds, representing nine different chemical scaffolds, with Cdc7 kinase inhibitory activity. Based on potency, we selected the lead compound (CKI-7) which was further characterized using kinase profiling, microarray experiments, and standard cell based cytotoxicity assays. These latter studies demonstrated that CKI-7 induced cytotoxicity of established leukemia and lymphoma cell lines in culture with inhibitory concentrations (IC50s) in the low nanomolar range. Significantly, CKI-7 likewise induced cytotoxicity of MDR1 overexpressing cell lines with similar IC50s, demonstrating that this novel compound can overcome a major mechanism of chemotherapy resistence in human tumor cells. We additonally demonstrate that CKI-7 induces cytotoxicity of patient-derived primary acute leukemia tumor cells (both chemotherapy naïve and relapsed/refractory samples) in vitro at similarly low nanomolar concentrations. In vivo dose-dependent anti-tumor activity of CKI-7 was subsequently demonstrated in a SCID-Beige mouse systemic tumor model utilzing a recently isolated Philadelphia chromosome positive acute lymphoblastic leukemia cell line (PhALL3.1). Standard cell cycle synchronization studies established that exposure to CKI-7 results in cell cycle dependent caspase 3 activation and apoptotic cell death. This cell death is the direct result of Cdc7 kinase inhibition by CKI-7 as demonstrated using a substrate biomarker assay. In conclusion, our data confirm that Cdc7 is a new promising target for cancer therapy, and that CKI-7, a selective small molecule inhibitor of this enzyme, is an equally promising novel cancer therapeutic agent.

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Ablation of RIP3 protects from dopaminergic neurodegeneration in experimental Parkinson’s disease

Cell Death and Disease ◽

10.1038/s41419-019-2078-z ◽

2019 ◽

Vol 10 (11) ◽

Cited By ~ 7

Author(s):

Pedro A. Dionísio ◽

Sara R. Oliveira ◽

Maria M. Gaspar ◽

Maria J. Gama ◽

Margarida Castro-Caldas ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cell Death ◽

Cultured Cells ◽

Substantia Nigra Pars Compacta ◽

Neuronal Cultures ◽

Interacting Protein ◽

Dopaminergic Neurodegeneration

Abstract Parkinson’s disease (PD) is driven by dopaminergic neurodegeneration in the substantia nigra pars compacta (SN) and striatum. Although apoptosis is considered the main neurodegenerative mechanism, other cell death pathways may be involved. In this regard, necroptosis is a regulated form of cell death dependent on receptor interacting protein 3 (RIP3), a protein also implicated in apoptosis and inflammation independently of its pro-necroptotic activity. Here, we explored the role of RIP3 genetic deletion in in vivo and in vitro PD models. Firstly, wild-type (Wt) and RIP3 knockout (RIP3ko) mice were injected intraperitoneally with MPTP (40 mg/kg, i.p.), and sacrificed after either 6 or 30 days. RIP3ko protected from dopaminergic neurodegeneration in the SN of MPTP-injected mice, but this effect was independent of necroptosis. In keeping with this, necrostatin-1s (10 mg/kg/day, i.p.) did not afford full neuroprotection. Moreover, MPTP led to DNA fragmentation, caspase-3 activation, lipid peroxidation and BAX expression in Wt mice, in the absence of caspase-8 cleavage, suggesting intrinsic apoptosis. This was mimicked in primary cortical neuronal cultures exposed to the active MPTP metabolite. RIP3 deficiency in cultured cells and in mouse brain abrogated all phenotypes. Curiously, astrogliosis was increased in the striatum of MPTP-injected Wt mice and further exacerbated in RIP3ko mice. This was accompanied by absence of microgliosis and reposition of glial cell line-derived neurotrophic factor (GDNF) levels in the striata of MPTP-injected RIP3ko mice when compared to MPTP-injected Wt mice, which in turn showed a massive GDNF decrease. RIP3ko primary mixed glial cultures also presented decreased expression of inflammation-related genes upon inflammatory stimulation. These findings hint at possible undescribed non-necroptotic roles for RIP3 in inflammation and MPTP-driven cell death, which can contribute to PD progression.

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