FGF10 mitigates doxorubicin-induced myocardial toxicity in mice via activation of FGFR2b/PHLDA1/AKT axis.

Doxorubicin is a common chemotherapeutic agent in clinic, but myocardial toxicity limits its use. Fibroblast growth factor (FGF) 10, a multifunctional paracrine growth factor, plays diverse roles in embryonic and postnatal heart development as well as in cardiac regeneration and repair. In this study we investigated the role of FGF10 as a potential modulator of doxorubicin-induced cardiac cytotoxicity and the underlying molecular mechanisms. Fgf10+/- mice and an inducible dominant negative FGFR2b transgenic mouse model (Rosa26rtTA; tet(O)sFgfr2b) were used to determine the effect of Fgf10 hypomorph or blocking of endogenous FGFR2b ligands activity on doxorubicin-induced myocardial injury. Acute myocardial injury was induced by a single injection of doxorubicin (25 mg/kg, i.p.). Then cardiac function was evaluated using echocardiography, and DNA damage, oxidative stress and apoptosis in cardiac tissue were assessed. We showed that doxorubicin treatment markedly decreased the expression of FGFR2b ligands including FGF10 in cardiac tissue of wild type mice, whereas Fgf10+/- mice exhibited a greater degree of oxidative stress, DNA damage and apoptosis as compared with the Fgf10+/+ control. Pre-treatment with recombinant FGF10 protein significantly attenuated doxorubicin-induced oxidative stress, DNA damage and apoptosis both in doxorubicin-treated mice and in doxorubicin-treated HL-1 cells and NRCMs. We demonstrated that FGF10 protected against doxorubicin-induced myocardial toxicity via activation of FGFR2/Pleckstrin homology-like domain family A member 1 (PHLDA1)/Akt axis. Overall, our results unveil a potent protective effect of FGF10 against doxorubicin-induced myocardial injury and identify FGFR2b/PHLDA1/Akt axis as a potential therapeutic target for patients receiving doxorubicin treatment.

Erratum: The WW domains dictate isoform-specific regulation of YAP1 stability and pancreatic cancer cell malignancy: Erratum.

[This corrects the article DOI: 10.7150/thno.42795.].

The WW domains dictate isoform-specific regulation of YAP1 stability and pancreatic cancer cell malignancy.

YAP1 is a key mediator of the Hippo pathway capable of exerting a profound effect on organ size as well as tumorigenesis. Alternative mRNA splicing of human YAP1 results in at least 8 protein isoforms that differ within the 2nd WW motif and the transcriptional activation domain. Methods: To investigate the isoform-specific differences in their mRNA expression, transcriptional activity and tumor-promoting function, we cloned cDNA encoding all of the eight YAP1 protein isoforms. Then, we examined their mRNA expression, subcellular localization, transcriptional regulation properties, interactions with key regulatory partners, and protein stability in response to changes in cell density, as well as their effects on pancreatic cancer cell malignancy both in vitro and in vivo. Results: Multiple YAP1 mRNA isoforms are expressed in commonly used pancreatic cancer lines as well as human pancreatic cancer PDX lines. Based on the analysis of heterologous reporter and endogenous target genes, all YAP1 isoforms are capable of activating transcription, albeit to a different extent. Importantly, we unveiled a marked discrepancy between the mRNA and protein expression levels of the YAP1-1 and YAP1-2 isoforms. We further discovered that the YAP1-2 isoform, which contains two tandem WW motifs, is less stable at the protein level, particularly at high cell densities. Mechanistically, we found that the presence of the 2nd WW motif in YAP1-2 facilitates the de novo formation of the YAP1-2/AMOT/LATS1 complex and contributes to a stronger binding of YAP1-2 to LATS1 and subsequently increased YAP1-2 ubiquitination and degradation by ß-TRCP. Conclusion: Our data reveals a potent effect of YAP1-1 on pancreatic cancer malignancy in vitro and in vivo and provides novel mechanistic insight into isoform-specific and cell density-dependent regulation of YAP1 stability, as well as its impact on cancer malignancy.

Fibroblast Growth Factors in the Management of Acute Kidney Injury Following Ischemia-Reperfusion.

Ischemia-reperfusion injury (IRI), which is triggered by a transient reduction or cessation of blood flow followed by reperfusion, is a significant cause of acute kidney injury (AKI). IRI can lead to acute cell death, tissue injury, and even permanent organ dysfunction. In the clinic, IRI contributes to a higher morbidity and mortality and is associated with an unfavorable prognosis in AKI patients. Unfortunately, effective clinical drugs to protect patients against the imminent risk of renal IRI or treat already existing AKI are still lacking. Fibroblast growth factors (FGFs) are important regulators of key biological and pathological processes, such as embryonic development, metabolic homeostasis and tumorigenesis through the regulation of cell differentiation, migration, proliferation and survival. Accumulating evidence suggests that altered expression of endogenous FGFs is associated with IRI and could be instrumental in mediating the repair process. Therefore, FGFs have been proposed as potential biomarkers in the clinic. More importantly, exogenous FGF ligands have been reported to protect against renal IRI and display promising features for therapy. In this review, we summarize the evidence and mechanisms of AKI following IRI with a focus on the therapeutic capacity of several members of the FGF family to treat AKI after IRI.

The repair and autophagy mechanisms of hypoxia-regulated bFGF-modified primary embryonic neural stem cells in spinal cord injury.

There is no effective strategy for the treatment of spinal cord injury (SCI), a devastating condition characterized by severe hypoxia and ischemic insults. In this study, we investigated the histology and pathophysiology of the SCI milieu in a rat model and found that areas of hypoxia were unevenly interspersed in compressed SCI. With this new knowledge, we generated embryonic neural stem cells (NSCs) expressing basic fibroblast growth factor (bFGF) under the regulation of five hypoxia-responsive elements (5HRE) using a lentiviral vector (LV-5HRE-bFGF-NSCs) to specifically target these hypoxic loci. SCI models treated with bFGF expressed by the LV-5HRE-bFGF-NSCs viral vector demonstrated improved recovery, increased neuronal survival, and inhibited autophagy in spinal cord lesions in the rat model due to the reversal of hypoxic conditions at day 42 after injury. Furthermore, improved functional restoration of SCI with neuron regeneration was achieved in vivo, accompanied by glial scar inhibition and the evidence of axon regeneration across the scar boundary. This is the first study to illustrate the presence of hypoxic clusters throughout the injury site of compressed SCI and the first to show that the transplantation of LV-5HRE-bFGF-NSCs to target this hypoxic microenvironment enhanced the recovery of neurological function after SCI in rats; LV-5HRE-bFGF-NSCs may therefore be a good candidate to evaluate cellular SCI therapy in humans.

Fibroblast Growth Factor 10 in Pancreas Development and Pancreatic Cancer.

The tenacious prevalence of human pancreatic diseases such as diabetes mellitus and adenocarcinoma has prompted huge research interest in better understanding of pancreatic organogenesis. The plethora of signaling pathways involved in pancreas development is activated in a highly coordinated manner to assure unmitigated development and morphogenesis in vertebrates. Therefore, a complex mesenchymal-epithelial signaling network has been implicated to play a pivotal role in organogenesis through its interactions with other germ layers, specifically the endoderm. The Fibroblast Growth Factor Receptor FGFR2-IIIb splicing isoform (FGFR2b) and its high affinity ligand Fibroblast Growth Factor 10 (FGF10) are expressed in the epithelium and mesenchyme, respectively, and therefore are well positioned to transmit mesenchymal to epithelial signaling. FGF10 is a typical paracrine FGF and chiefly mediates biological responses by activating FGFR2b with heparin/heparan sulfate (HS) as cofactor. A substantial number of studies using genetically engineered mouse models have demonstrated an essential role of FGF10 in the development of many organs and tissues including the pancreas. During mouse embryonic development, FGF10 signaling is crucial for epithelial cell proliferation, maintenance of progenitor cell fate and branching morphogenesis in the pancreas. FGF10 is also implicated in pancreatic cancer, and that overexpression of FGFR2b is associated with metastatic invasion. A thorough understanding of FGF10 signaling machinery and its crosstalk with other pathways in development and pathological states may provide novel opportunities for pancreatic cancer targeted therapy and regenerative medicine.

Transplantation of bFGF-expressing neural stem cells promotes cell migration and functional recovery in rat brain after transient ischemic stroke.

Cerebrovascular disease such as stroke is one of the most common diseases in the aging population, and neural stem cells (NSCs) transplantation may provide an alternative therapy for cerebral ischemia. However, a hostile microenvironment in the ischemic brain offers is challenging for the survival of the transplanted cells. Considering the neuroprotective role of basic fibroblast growth factor (bFGF), the present study investigated whether bFGF gene-modified NSCs could improve the neurological function deficit after transient middle cerebral artery occlusion (MCAO) in adult male Sprague-Dawley rats. These rats were intravenously injected with modified NSCs (5×106/200 µL) or vehicle 24 h after MCAO. Histological analysis was performed on days 7 and 28 after tMCAO. The survival, migration, proliferation, and differentiation of the transplanted modified C17.2 cells in the brain were improved. In addition, the intravenous infusion of NSCs and bFGF gene-modified C17.2 cells improved the functional recovery as compared to the control. Furthermore, bFGF promoted the C17.2 cell growth, survival, and differentiation into mature neurons within the infarct region. These data suggested that bFGF gene-modified NSCs have the potential to be a therapeutic agent in brain ischemia.

11ß-HSD1 inhibition ameliorates diabetes-induced cardiomyocyte hypertrophy and cardiac fibrosis through modulation of EGFR activity.

11ß-HSD1 has been recognized as a potential therapeutic target for type 2 diabetes. Recent studies have shown that hyperglycemia leads to activation of 11ß-HSD1, increasing the intracellular glucocorticoid levels. Excess glucocorticoids may lead to the clinical manifestations of cardiac injury. Therefore, the aim of this study is to investigate whether 11ß-HSD1 activation contributes to the development of diabetic cardiomyopathy. To investigate the role of 11ß-HSD1, we administered a selective 11ß-HSD1 inhibitor in type 1 and type 2 murine models of diabetes and in cultured cardiomyocytes. Our results show that diabetes increases cortisone levels in heart tissues. 11ß-HSD1 inhibitor decreased cortisone levels and ameliorated all structural and functional features of diabetic cardiomyopathy including fibrosis and hypertrophy. We also show that high levels of glucose caused cardiomyocyte hypertrophy and increased matrix protein deposition in culture. Importantly, inhibition of 11ß-HSD1 attenuated these changes. Moreover, we show that 11ß-HSD1 activation mediates these changes through modulating EGFR phosphorylation and activity. Our findings demonstrate that 11ß-HSD1 contributes to the development of diabetic cardiomyopathy through activation of glucocorticoid and EGFR signaling pathway. These results suggest that inhibition of 11ß-HSD1 might be a therapeutic strategy for diabetic cardiomyopathy, which is independent of its effects on glucose homeostasis.

Effect of pulse high-volume hemofiltration on Toll-like receptor in patients with severe sepsis.

The expression level and prognosis of Toll-like receptor 2 (TLR2) mRNA in peripheral blood mononuclear cells of patients with severe sepsis after applying pulse high-volume hemofiltration (PHVHF) were investigated. Sustained PHVHF treatment was carried out on 40 patients on the basis of conventional treatment for up to 72 h. Acute physiology and chronic health evaluation (APACHE) II scores of patients were compared before and after the treatment. CD4+, CD8+ lymphocyte counts and ratios in the peripheral blood were detected using FASort before and 24 and 48 h of PHVHF treatment. Enzyme-linked immunosorbent assay was adopted to detect tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) concentrations in plasma at different time points before and after 24, 48 and 72 h of treatment, while semi-quantitative reverse transcription-polymerase chain reaction technology was used to test TLR2 mRNA expression. After PHVHF treatment, APACHE II, Sequential Organ Failure Assessment scores were decreased (P<0.05). After 72 h of PHVHF treat-ment, TNF-α, IL-10, TLR2 mRNA expression levels in the plasma of patients were significantly decreased compared to before treatment (P<0.05), and the IL-10 / TNF-α ratio was much higher than before treatment (p<0.05). In conclusion, PHVHF can restore the pro-inflammatory/anti-inflammatory balance of the body, thereby improving the overall condition of the patients by removing inflammatory mediators and lowering TLR2 expression of mononuclear cell surface in peripheral blood.

Inhibition of mitogen-activated protein kinases/nuclear factor κB-dependent inflammation by a novel chalcone protects the kidney from high fat diet-induced injuries in mice.

The prevalence of obesity has increased dramatically worldwide leading to increases in obesity-related complications, such as obesity-related glomerulopathy (ORG). Obesity is a state of chronic, low-grade inflammation, and increased inflammation in the adipose and kidney tissues has been shown to promote the progression of renal damage in obesity. Current therapeutic options for ORG are fairly limited and, as a result, we are seeing increased rates of progression to end-stage renal disease. Chalcones are a class of naturally occurring compounds with various pharmacological properties. 1-(3,4-Dihydroxyphenyl)-3-(2-methoxyphenyl)prop-2-en-1-one (L2H17) is a chalcone that we have previously synthesized and found capable of inhibiting the lipopolysaccharide-induced inflammatory response in macrophages. In this study, we investigated L2H17's effect on obesity-induced renal injury using palmitic acid-induced mouse peritoneal macrophages and high fat diet-fed mice. Our results indicate that L2H17 protects against renal injury through the inhibition of the mitogen-activated protein kinase/nuclear factor κB pathways significantly by decreasing the expression of proinflammatory cytokines and cell adhesion molecules and improving kidney histology and pathology. These findings lead us to believe that L2H17, as an anti-inflammatory agent, can be a potential therapeutic option in treating ORG.

Intravenously delivered neural stem cells migrate into ischemic brain, differentiate and improve functional recovery after transient ischemic stroke in adult rats.

Stem cell transplantation may provide an alternative therapy to promote functional recovery after various neurological disorders including cerebral infarct. Due to the minimal immunogenicity and neuronal differentiation potential of neural stem cells (NSCs), we tested whether intravenous administration of mice-derived C17.2 NSCs could improve neurological function deficit and cerebral infarction volume after ischemic stroke in rats. Additionally, we evaluated the survival, migration, proliferation, and differentiation capacity of transplanted NSCs in the rat brain. Intravenous infusion of NSCs after middle cerebral artery occlusion (MCAO) showed better performance in neurobiological severity scores after MCAO compared to control. However, the volume of cerebral infarction was not different at 7 days after MCAO compared with control. Transplanted NSCs were detected in the ischemic region but not in the contralateral hemisphere. NSCs differentiated into neurons or astrocytes after MCAO. These data suggest that intravenously transplanted NSCs can migrate, proliferate, and differentiate into neurons and astrocytes in the rat brain with focal ischemia and improve functional recovery.

Nerve growth factor improves functional recovery by inhibiting endoplasmic reticulum stress-induced neuronal apoptosis in rats with spinal cord injury.

BACKGROUND: Endoplasmic reticulum (ER) stress-induced apoptosis plays a major role in various diseases, including spinal cord injury (SCI). Nerve growth factor (NGF) show neuroprotective effect and improve the recovery of SCI, but the relations of ER stress-induced apoptosis and the NGF therapeutic effect in SCI still unclear. METHODS: Young adult female Sprague-Dawley rats's vertebral column was exposed and a laminectomy was done at T9 vertebrae and moderate contusion injuries were performed using a vascular clip. NGF stock solution was diluted with 0.9% NaCl and administered intravenously at a dose of 20 µg/kg/day after SCI and then once per day until they were executed. Subsequently, the rats were executed at 1d, 3 d, 7d and 14d. The locomotor activities of SCI model rats were tested by the 21-point Basso-Beattie-Bresnahan (BBB) locomotion scale, inclined plane test and footprint analysis. In addition, Western blot analysis was performed to identify the expression of ER-stress related proteins including CHOP, GRP78 and caspase-12 both in vivo and in vitro. The level of cell apoptosis was determined by TUNEL in vivo and Flow cytometry in vitro. Relative downstream signals Akt/GSK-3ß and ERK1/2were also analyzed with or without inhibitors in vitro. RESULTS: Our results demonstrated that ER stress-induced apoptosis was involved in the injury of SCI model rats. NGF administration improved the motor function recovery and increased the neurons survival in the spinal cord lesions of the model rats. NGF decreases neuron apoptosis which measured by TUNEL and inhibits the activation of caspase-3 cascade. The ER stress-induced apoptosis response proteins CHOP, GRP78 and caspase-12 are inhibited by NGF treatment. Meanwhile, NGF administration also increased expression of growth-associated protein 43 (GAP43). The administration of NGF activated downstream signals Akt/GSK-3ß and ERK1/2 in ER stress cell model in vitro. CONCLUSION: The neuroprotective role of NGF in the recovery of SCI is related to the inhibition of ER stress-induced cell death via the activation of downstream signals, also suggested a new trend of NGF translational drug development in the central neural system injuries which involved in the regulation of chronic ER stress.