Pharmacologic induction of PGC-1α stimulates fetal haemoglobin gene expression.

Sickle cell disease (SCD) is a genetic disorder that affects millions around the world. Enhancement of fetal γ-globin levels and fetal haemoglobin (HbF) production in SCD patients leads to diminished severity of many clinical features of the disease. We recently identified the transcriptional co-activator PGC-1α as a new protein involved in the regulation of the globin genes. Here, we report that upregulation of PGC-1α by infection with a lentivirus expressing PGC-1α or by the small-molecule PGC-1α agonist ZLN005 in human primary erythroid progenitor CD34+ cells induces both fetal γ-globin mRNA and protein expression as well as the percentage of HbF-positive cell (F cells) without significantly affecting cell proliferation and differentiation. We further found that the combination of ZLN005 and hydroxyurea (hydroxycarbamide) exhibited an additive effect on the expression of γ-globin and the generation of F cells from cultured CD34+ cells. In addition, ZLN005 induced robust expression of the murine embryonic ßh1-globin gene and to a lesser extent, human γ-globin gene expression in sickle mice. These findings suggest that activation of PGC-1α by ZLN005 might provide a new path for modulating HbF levels with potential therapeutic benefit in ß-hemoglobinopathies.

Medioresinol as a novel PGC-1α activator prevents pyroptosis of endothelial cells in ischemic stroke through PPARα-GOT1 axis.

AIM: Brain microvascular endothelial cells (BMVECs), as the important structure of blood-brain barrier (BBB), play a vital role in ischemic stroke. Pyroptosis of different cells in the brain may aggravate cerebral ischemic injury, and PGC-1α plays a major role in pyroptosis. However, it is not known whether BMVECs undergo pyroptosis after ischemic stroke and whether PGC-1α activator Medioresinol (MDN) we discovered may be useful against pyroptosis of endothelial cells and ischemic brain injury. METHODS: For in vitro experiments, the bEnd.3 cells and BMVECs under oxygen and glucose-deprivation (OGD) were treated with or without MDN, and the LDH release, tight junction protein degradation, GSDMD-NT membrane location and pyroptosis-associated proteins were evaluated. For in vivo experiments, mice underwent transient middle cerebral artery occlusion (tMCAO) for ischemia model, and the neuroprotective effects of MDN were measured by infarct volume, the permeability of BBB and pyroptosis of BMVECs. For mechanistic study, effects of MDN on the accumulation of phenylalanine, mitochondrial reactive oxygen species (mtROS) were tested by untargeted metabolomics and MitoSOX Red probe, respectively. RESULTS: BMVECs underwent pyroptosis after ischemia. MDN dose-dependently activated PGC-1α, significantly reduced pyroptosis, mtROS and the expressions of pyroptosis-associated proteins (NLRP3, ASC, cleaved caspase-1, IL-1ß, GSDMD-NT), and increased ZO-1 and Occludin protein expressions in BMVECs. In tMCAO mice, MDN remarkably reduced brain infarct volume and the permeability of BBB, inhibited pyroptosis of BMVECs, and promoted long-term neurobehavioral functional recovery. Mechanistically, MDN promoted the interaction of PGC-1α with PPARα to increase PPARα nuclear translocation and transcription activity, further increased the expression of GOT1 and PAH, resulting in enhanced phenylalanine metabolism to reduce the ischemia-caused phenylalanine accumulation and mtROS and further ameliorate pyroptosis of BMVECs. CONCLUSION: In this study, we for the first time discovered that pyroptosis of BMVECs was involved in the pathogenesis of ischemic stroke and MDN as a novel PGC-1α activator could ameliorate the pyroptosis of endothelial cells and ischemic brain injury, which might attribute to reduction of mtROS through PPARα/GOT1 axis in BMVECs. Taken together, targeting endothelial pyroptosis by MDN may provide alternative therapeutics for brain ischemic stroke.

ZLN005 protects cardiomyocytes against high glucose-induced cytotoxicity by promoting SIRT1 expression and autophagy.

Diabetic cardiomyopathy increases the risk for the development of heart failure independent of coronary artery disease and hypertension. Either type 1 or type 2 diabetes is often accompanied by varying degrees of hyperglycemia, which has been proven to induce myocardial apoptosis in animal models. Recently, a novel small molecule, ZLN005, has been reported to show antidiabetic efficacy in a mouse model, possibly by induction of PGC-1α expression. In this study, we investigated whether ZLN005 protects cardiomyocytes against high glucose-induced cytotoxicity and the mechanisms involved. Neonatal mouse cardiomyocytes were incubated with media containing 5.5 or 33mM glucose for 24h in the presence or absence of ZLN005. ZLN005 treatment led to ameliorated cardiomyocyte oxidative injury, enhanced cell viability, and reduced apoptosis in the high glucose environment. Western blot analysis revealed that high glucose suppressed cardiomyocyte autophagy, whereas ZLN005 increased the expression of autophagy marker proteins ATG5, beclin1, and LC3 II/LC3 I; this increase was accompanied by increased expression of SIRT1. Furthermore, EX527, a SIRT1-specific inhibitor, weakened the protective effects of ZLN005 on cardiomyocytes subjected to high glucose. Taken together, these results suggest that ZLN005 suppresses high glucose-induced cardiomyocyte injury by promoting SIRT1 expression and autophagy.

ZLN005 alleviates PBDE-47 induced impairment of mitochondrial translation and neurotoxicity through PGC-1α/ERRα axis.

Recent studies are identified the mitochondria as critical targets of 2, 2', 4, 4'-tetrabromodiphenyl ether (PBDE-47) induced neurotoxicity. This study aimed at examining the impact of PBDE-47 exposure on mitochondrial translation, and its subsequent effect on PBDE-47 neurotoxicity. The Sprague-Dawley (SD) rat model and neuroendocrine pheochromocytoma (PC12) cells were adopted for the measurements of mitochondrial ATP levels, mitochondrial translation products, and expressions of important mitochondrial regulators, such as required meiotic nuclear division 1 (RMND1), estrogen-related receptor α (ERRα), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α). To delve into the role of PGC-1α/ERRα axis in mitochondrial translation, 2-(4-tert-butylphenyl) benzimidazole (ZLN005) was employed. Both cellular and animal model results shown that PBDE-47 impeded PGC-1α/ERRα axis and mitochondrial translation. PBDE-47 suppressed mitochondrial function in rat hippocampus and PC12 cells by decreasing relative mitochondrial DNA (mtDNA) content, mitochondrial translation products, and mitochondrial ATP levels. Particularly, ZLN005 reversed PBDE-47 neurotoxicity by enhancing mitochondrial translation through activation of PGC-1α/ERRα axis, yet suppressing PGC-1α with siRNA attenuates its neuroprotective effect in vitro. In conclusion, this work highlights the importance of mitochondrial translation in PBDE-47 neurotoxicity by presenting results from cellular and animal models and suggests a potential therapeutic approach through activation of PGC-1α/ERRα axis. ENVIRONMENTAL IMPLICATION: PBDEs have attracted extensive attention because of their high lipophilicity, persistence, and detection levels in various environmental media. Increasing evidence has shown that neurodevelopmental disorders in children are associated with PBDE exposure. Several studies have also found that perinatal PBDE exposure can cause long-lasting neurobehavioral abnormalities in experimental animals. Our recent studies have also demonstrated the impact of PBDE-47 exposure on mitochondrial biogenesis and dynamics, leading to memory and neurobehavioral deficits. Therefore, we explore whether the pathological mechanism of PBDE-47-induced neurotoxicity involves the regulation of mitochondrial translation through the PGC-1α/ERRα axis.

ZLN005, a PGC-1α Activator, Protects the Liver against Ischemia-Reperfusion Injury and the Progression of Hepatic Metastases.

BACKGROUND: Exercise can promote sustainable protection against cold and warm liver ischemia-reperfusion injury (IRI) and tumor metastases. We have shown that this protection is by the induction of hepatic mitochondrial biogenesis pathway. In this study, we hypothesize that ZLN005, a PGC-1α activator, can be utilized as an alternative therapeutic strategy. METHODS: Eight-week-old mice were pretreated with ZLN005 and subjected to liver warm IRI. To establish a liver metastatic model, MC38 cancer cells (1 × 106) were injected into the spleen, followed by splenectomy and liver IRI. RESULTS: ZLN005-pretreated mice showed a significant decrease in IRI-induced tissue injury as measured by serum ALT/AST/LDH levels and tissue necrosis. ZLN005 pretreatment decreased ROS generation and cell apoptosis at the site of injury, with a significant decrease in serum pro-inflammatory cytokines, innate immune cells infiltration, and intrahepatic neutrophil extracellular trap (NET) formation. Moreover, mitochondrial mass was significantly upregulated in hepatocytes and maintained after IRI. This was confirmed in murine and human hepatocytes treated with ZLN005 in vitro under normoxic and hypoxic conditions. Additionally, ZLN005 preconditioning significantly attenuated tumor burden and increased the percentage of intratumoral cytotoxic T cells. CONCLUSIONS: Our study highlights the effective protection of ZLN005 pretreatment as a therapeutic alternative in terms of acute liver injury and tumor metastases.

ZLN005 Alleviates In Vivo and In Vitro Renal Fibrosis via PGC-1α-Mediated Mitochondrial Homeostasis.

Currently, chronic kidney disease (CKD) is one of the most common diseases; it is also a serious threat to human health due to its high mortality, and its treatment is still a major clinical challenge. Mitochondrial dyshomeostasis plays an important role in the development of CKD. ZLN005 is a novel peroxisome-proliferator-activated receptor-γ coactivator-1α (PGC-1α) activator from our laboratory. To explore whether ZLN005 can protect against CKD in vivo and in vitro, a unilateral ureteral obstruction (UUO) model and TGF-ß1-treated renal tubular epithelial cells (TECs), respectively, were used in this study. We found that ZLN005-administrated UUO mice showed less kidney damages than control mice, as indicated by the reduced expression of fibrotic biomarkers in the kidney of UUO mice. ZLN005 treatment also alleviated the TGF-ß1-induced fibrotic phenotype and lipid accumulation in TECs. Our study demonstrated ZLN005 treatment improved mitochondrial homeostasis at least partially via the activation of PGC-1α, thus maintaining mitochondria function and energy homeostasis. In summary, ZLN005 treatment ameliorates UUO-induced renal fibrosis, providing conceptional support for mitochondria-targeting therapies for chronic kidney disease.

Insufficient sleep disrupts glucose metabolism during pregnancy by inhibiting PGC-1α.

Background: Gestational diabetes mellitus (GDM) impacted about 17 million pregnancies globally and predisposes both the mother and her offspring to metabolic disorders. Insufficient sleep has been shown to be associated with GDM. This study aimed to explore the molecular link between sleep and GDM. Methods: The sleep of pregnant mice was disturbed with motion a rod and the mice received either dimethyl sulfoxide (DMSO) or ZLN005. Insulin resistance was assessed by intraperitoneal glucose tolerance test (GTT). Adenosine triphosphate (ATP), reactive oxygen species (ROS), and cytokines were measured with respective commercial kits. Gene expression was analyzed with quantitative polymerase chain reaction (qPCR), western blot, and/or immunohistochemistry (IHC). Results: Sleep disturbance increased blood glucose level and insulin resistance, increased ROS and inflammatory cytokines, and reduced ATP level in pregnant mice. The expression levels of PGC-1α and downstream metabolic genes and antioxidant genes in pregnant mouse muscle were inhibited by sleep disturbance. ZLN005 promoted expression of PGC-1α and its target genes, increased muscle ATP level, decreased muscle ROS, and reduced blood glucose level and insulin resistance in sleep disturbed pregnant mice, indicating that PGC-1α played a critical role in sleep insufficiency caused GDM and might be a target for intervention. Conclusions: PGC-1 was a key player in the sleep disorder GDM and might be a target for treatment.

ZLN005 protects against ischemia-reperfusion-induced kidney injury by mitigating oxidative stress through the restoration of mitochondrial fatty acid oxidation.

To date, the treatment of acute kidney injury (AKI) remains a difficult problem for clinicians. In the present study, we assessed whether ZLN005, a novel peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) agonist, can protect against ischemic AKI in vivo and in vitro. Notably, ZLN005 treatment significantly alleviated Ischemia-reperfusion (I/R)-induced tubular injury and reversed the decrease in hypoxia-reoxygenation-induced cell viability by restoring PGC-1α expression in a dose-dependent manner. This beneficial effect of ZLN005 was associated with the preservation of mitochondrial fatty acid oxidation (MitoFAO) and the alleviation of oxidative stress. Cotreatment with etomoxir, a specific inhibitor of carnitine palmitoyltransferase-1α (CPT-1α) activity, or CPT-1α siRNA abrogated ZLN005-induced antistress responses by mitigating reactive oxygen species production and decreasing apoptosis under ischemia-hypoxia conditions by suppressing MitoFAO. Further studies revealed that activation of endoplasmic reticulum (ER) stress may be involved in the effect of CPT-1α inhibition observed in vivo and in vitro. Collectively, our results suggest that ZLN005 confers a protective effect on I/R-induced kidney injury by mitigating ER stress through the restoration of MitoFAO by targeting PGC-1α.

ß2-adrenoreceptor agonist ameliorates mechanical allodynia in paclitaxel-induced neuropathic pain via induction of mitochondrial biogenesis.

Chemotherapy-induced neuropathic pain is a debilitating and common side effect of cancer treatment and so far no effective drug is available for treatment of the serious side effect. Previous studies have demonstrated ß2-adrenoreceptor (ADRB2) agonists can attenuate neuropathic pain. However, the role of ADRB2 in paclitaxel -induced neuropathic pain (PINP) remains unclear. In this study, we investigated the effect of formoterol, a long-acting ADRB2 agonist, and related mechanisms in PINP. A rat model of PINP was established by intraperitoneal injection of paclitaxel (2 mg/kg) every other day with a final cumulative dose of 8 mg/kg. Hind paw withdrawal thresholds (PWTs) in response to von Frey filament stimuli were used to evaluate mechanical allodynia. Western blot was used to examine the expression of ADRB2, peroxisome proliferator-activated receptor coactivator-1α (PGC-1α), nuclear respiratory factors 1 (NRF1) and mitochondrial transcription factor A (TFAM) and the immunofluorescence was to detect the cellular localization of ADRB2 and PGC-1α in the spinal cord. Moreover, we measured mitochondrial DNA (mtDNA) copy number by qPCR. In our study, formoterol attenuated established PINP and delayed the onset of PINP. Formoterol restored ADRB2 expression as well as mtDNA copy number and PGC-1α, NRF1, and TFAM protein expression, which are major genes involved in mitochondrial biogenesis, in the spinal cord of PINP rats. Moreover, we found the analgesic effect of formoterol against PINP was partially abolished by PGC-1α inhibitor SR-18292. Collectively, these results demonstrated the activation of ADRB2 with formoterol ameliorates PINP at least partially through induction of mitochondrial biogenesis.

p53/PGC­1α­mediated mitochondrial dysfunction promotes PC3 prostate cancer cell apoptosis.

Data for p53 mutation in prostate cancer in The Cancer Genome Atlas database revealed that >85% of p53 mutations occurred in the p53 DNA binding domain. These mutations not only severely damage the function of the p53 protein, but also reduce the disease­free survival of patients. Peroxisome proliferator­activated receptor γ coactivator­1α (PGC­1α) is involved in the regulation of mitochondrial function and is highly expressed in prostate cancer PC3 and DU145 cells with p53 deletion or mutation. However, whether p53 negatively regulates PGC­1α in prostate cancer cells remains to be elucidated. In the present study, p53 overexpression was induced in prostate cancer PC3 cells. Subsequently, the expression levels of PGC­1α and alterations to mitochondrial function were assessed. Moreover, PGC­1α was activated in prostate cancer PC3 cells using ZLN005 to investigate alterations to mitochondrial function and cell apoptosis. The present study revealed that p53 decreased the expression and nuclear localization of the PGC­1α protein and induced mitochondrial dysfunction. Activation of PGC­1α partially reversed p53­mediated mitochondrial dysfunction. Inhibition of the p53/PGC­1α pathway on mitochondrial biogenesis and fission­/fusion­associated gene and protein expression were associated with mitochondrial dysfunction. p53/PGC­1α­mediated mitochondrial dysfunction promoted apoptosis of PC3 prostate cancer cells. The results indicated that PGC­1α is an essential target of p53­induced apoptosis in prostate cancer cells and indicated that targeting PGC­1α may provide a new therapeutic strategy for prostate cancer.

PGC-1α activator ZLN005 promotes maturation of cardiomyocytes derived from human embryonic stem cells.

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great potential in biomedical applications. However, the immature state of cardiomyocytes obtained using existing protocols limits the application of hPSC-CMs. Unlike adult cardiac myocytes, hPSC-CMs generate ATP through an immature metabolic pathway-aerobic glycolysis, instead of mitochondrial oxidative phosphorylation (OXPHOS). Hence, metabolic switching is critical for functional maturation in hPSC-CMs. Peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) is a key regulator of mitochondrial biogenesis and metabolism, which may help promote cardiac maturation during development. In this study, we investigated the effects of PGC-1α and its activator ZLN005 on the maturation of human embryonic stem cell-derived cardiomyocyte (hESC-CM). hESC-CMs were generated using a chemically defined differentiation protocol and supplemented with either ZLN005 or DMSO (control) on differentiating days 10 to 12. Biological assays were then performed around day 30. ZLN005 treatment upregulated the expressions of PGC-1α and mitochondrial function-related genes in hESC-CMs and induced more mature energy metabolism compared with the control group. In addition, ZLN005 treatment increased cell sarcomere length, improved cell calcium handling, and enhanced intercellular connectivity. These findings support an effective approach to promote hESC-CM maturation, which is critical for the application of hESC-CM in disease modeling, drug screening, and engineering cardiac tissue.