Hepatocyte Growth Factor Gene Therapy Slows Down the Progression of Diabetic Nephropathy in db/db Mice

Inflammatory bowel disease-associated intestinal fibrosis

Fibrosis is characterized by a proliferation of fibroblasts and excessive extracellular matrix following chronic inflammation, and this replacement of organ tissue with fibrotic tissue causes a loss of function. Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract, and intestinal fibrosis is common in IBD patients, resulting in several complications that require surgery, such as a stricture or penetration. This review describes the pathogenesis and various factors involved in intestinal fibrosis in IBD, including cytokines, growth factors, epithelial-mesenchymal and endothelial-mesenchymal transitions, and gut microbiota. Furthermore, histopathologic findings and scoring systems used for stenosis in IBD are discussed, and differences in the fibrosis patterns of ulcerative colitis and Crohn's disease are compared. Biomarkers and therapeutic agents targeting intestinal fibrosis are briefly mentioned at the end.

Gene expression-based analysis identified NTNG1 and HGF as biomarkers for diabetic kidney disease

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease. Because the molecular mechanisms of DKD are not fully understood, exploration of hub genes and the mechanisms underlying this disease are essential for elucidating the pathogenesis and progression of DKD. Accordingly, in this study, we performed an analysis of gene expression in DKD. The differentially expressed genes (DEGs) included 39 upregulated genes and 113 downregulated genes in the GSE30528 dataset and 127 upregulated genes and 18 downregulated genes in the GSE30529 dataset. Additionally, functional analyses were performed to determine the roles of DEGs using glomeruli samples from patients with DKD and healthy controls from the GSE30528 dataset and using tubule samples from patients with DKD and healthy controls from the GSE30529 dataset. These DEGs were enriched in pathways such as the Wnt signaling pathway, metabolic pathways, and the mammalian target of rapamycin signaling pathway in the GSE30528 dataset and the longevity regulating pathway and Ras signaling pathway in the GSE30529 dataset. Moreover, a protein-protein interaction network was constructed using the identified DEGs, and hub gene analysis was performed. Furthermore, correlation analyses between key genes and pathological characteristics of DKD indicated that CCR4, NTNG1, HGF and ISL1 are related to DKD, and NTNG1 and HGF may server as diagnostic biomarkers in DKD using the receiver-operator characteristic (ROC) curve. Collectively, our findings established 2 reliable biomarkers for DKD.

Soluble cMet levels in urine are a significant prognostic biomarker for diabetic nephropathy

Hepatocyte growth factor and its receptor cMet activate biological pathways necessary for repair and regeneration following kidney injury. Here, we evaluated the clinical role of urinary cMet as a prognostic biomarker in diabetic nephropathy (DN). A total of 218 patients with DN were enrolled in this study. We examined the association of urine cMet levels and long-term outcomes in patients with DN. The levels of urinary cMet were higher in patients with decreased renal function than in patients with relatively preserved renal function (5.25 ± 9.62 ng/ml versus 1.86 ± 4.77 ng/ml, P = 0.001). A fully adjusted model revealed that a urinary cMet cutoff of 2.9 ng/mL was associated with a hazard ratio for end-stage renal disease of 2.33 (95% confidence interval 1.19–4.57, P = 0.014). The addition of urinary cMet to serum creatinine and proteinuria provided the highest net reclassification improvement. We found that in primary cultured human glomerular endothelial cells, TGFβ treatment induced fibrosis, and the protein expression levels of collagen I, collagen IV, fibronectin, and αSMA were decreased after administration of an agonistic cMet antibody. In conclusion, elevated levels of urinary cMet at the time of initial diagnosis could predict renal outcomes in patients with DN.

Effective control of neuropathic pain by transient expression of hepatocyte growth factor in a mouse chronic constriction injury model

Hepatocyte growth factor (HGF) is a multifunctional protein that contains angiogenic and neurotrophic properties. In the current study, we investigated the analgesic effects of HGF by using a plasmid DNA that was designed to express 2 isoforms of human HGF—pCK-HGF-X7 (or VM202)—in a chronic constriction injury (CCI) –induced mouse neuropathic pain model. Intramuscular injection of pCK-HGF-X7 into proximal thigh muscle induced the expression of HGF in the muscle, sciatic nerve, and dorsal root ganglia (DRG). This gene transfer procedure significantly attenuated mechanical allodynia and thermal hyperalgesia after CCI. Injury-induced expression of activating transcription factor 3, calcium channel subunit α2δ1, and CSF1 in the ipsilateral DRG neurons was markedly down-regulated in the pCK-HGF-X7–treated group, which suggested that HGF might exert its analgesic effects by inhibiting pain-mediating genes in the sensory neurons. In addition, suppressed CSF1 expression in DRG neurons by pCK-HGF-X7 treatment was accompanied by a noticeable suppression of the nerve injury–induced glial cell activation in the spinal cord dorsal horn. Taken together, our data show that pCK-HGF-X7 attenuates nerve injury–induced neuropathic pain by inhibiting pain-related factors in DRG neurons and subsequent spinal cord glial activation, which suggests its therapeutic efficacy in the treatment of neuropathic pain.—Nho, B., Lee, J., Lee, J., Ko, K. R., Lee, S. J., Kim, S. Effective control of neuropathic pain by transient expression of hepatocyte growth factor in a mouse chronic constriction injury model.

Microbubbles and Ultrasound: Therapeutic Applications in Diabetic Nephropathy

Diabetic nephropathy (DN) remains one of the most common causes of end-stage renal disease. Current therapeutic strategies aiming at optimization of serum glucose and blood pressure are beneficial in early stage DN, but are unable to fully prevent disease progression. With the limitations of current medical therapies and the shortage of available donor organs for kidney transplantation, the need for novel therapies to address DN complications and prevent progression towards end-stage renal failure is crucial. The development of ultrasound technology for non-invasive and targeted in-vivo gene delivery using high power ultrasound and carrier microbubbles offers great therapeutic potential for the prevention and treatment of DN. The promising results from preclinical studies of ultrasound-mediated gene delivery (UMGD) in several DN animal models suggest that UMGD offers a unique, non-invasive platform for gene- and cell-based therapies targeted against DN with strong clinical translation potential.

Virus integration and genome influence in approaches to stem cell based therapy for andro-urology

Despite the potential of stem cells in cell-based therapy, major limitations such as cell retention, ingrowth, and trans-differentiation after implantation remain. One technique for genetic modification of cells for tissue repair is the introduction of specific genes using molecular biology techniques, such as virus integration, to provide a gene that adds new functions to enhance cellular function, and to secrete trophic factors for recruiting resident cells to participate in tissue repair. Stem cells can be labeled to track cell survival, migration, and lineage. Increasing evidence demonstrates that cell therapy and gene therapy in combination remarkably improve differentiation of implanted mesenchymal stromal cells (MSCs), revascularization, and innervation in genitourinary tissues, especially to treat urinary incontinence, erectile dysfunction, lower urinary tract reconstruction, and renal failure. This review discusses the benefits, safety, side effects, and alternatives for using genetically modified MSCs in tissue regeneration in andro-urology.

Hepatocyte Growth Factor Isoforms in Tissue Repair, Cancer, and Fibrotic Remodeling

Hepatocyte growth factor (HGF), also known as scatter factor (SF), is a pleotropic factor required for normal organ development during embryogenesis. In the adult, basal expression of HGF maintains tissue homeostasis and is up-regulated in response to tissue injury. HGF expression is necessary for the proliferation, migration, and survival of epithelial and endothelial cells involved in tissue repair in a variety of organs, including heart, lung, kidney, liver, brain, and skin. The administration of full length HGF, either as a protein or using exogenous expression methodologies, increases tissue repair in animal models of tissue injury and increases angiogenesis. Full length HGF is comprised of an N-terminal hairpin turn, four kringle domains, and a serine protease-like domain. Several naturally occurring alternatively spliced isoforms of HGF were also identified. The NK1 variant contains the N-terminal hairpin and the first kringle domain, and the NK2 variant extends through the second kringle domain. These alternatively spliced forms of HGF activate the same receptor, MET, but they differ from the full length protein in their cellular activities and their biological functions. Here, we review the species-specific expression of the HGF isoforms, their regulation, the signal transduction pathways they activate, and their biological activities.

Hepatocyte growth factor reduces hypertrophy of skin scar: in vivo study

OBJECTIVE

Excessive collagen deposition causes hypertrophic scarring after dermal wound repair. It can be functionally and cosmetically debilitating to many patients. A direct approach to the control of scar tissue formation is pharmacological regulation of collagen synthesis and deposition. Some studies reported that hepatocyte growth factor (HGF) plays an important role in scar formation. Hepatocyte growth factor can improve tissue fibrosis and reverse the imbalance of collagen metabolism. However, an in vivo study has not been reported concerning the use of HGF in controlling hypertrophy of skin scar until now.

METHODS

The authors tested the ability of HGF to reduce hypertrophic scar formation in a rabbit ear model. After the placement of three 5-mm dermal wounds on each ear, New Zealand white rabbits received HGF subcutaneously in the left ear at 4 time points on postwounding days 15, 30, 45, and 90. The left ear of each animal served as a control without HGF treatment. Scars were harvested at postoperative 6 months and scar hypertrophy quantified by measurement of the scar elevation index.

RESULTS

The experimental data showed that treatment of scars with HGF decreased scar formation. The HGF treatment resulted in a statistically significant reduction in the scar elevation index (P < .01).

CONCLUSION

The authors' results indicate the potential use of HGF to treat hypertrophic scarring, which shows important significance for antiscarring therapy.

Contrast ultrasound and targeted microbubbles: diagnostic and therapeutic applications in progressive diabetic nephropathy

Diabetic nephropathy remains one of the most common causes for end-stage renal disease worldwide. Although therapies aimed at optimizing glycemic control and systemic blood pressure have benefit, the reduction in progressive nephropathy remains modest at best. Thus, research continues to focus on newer therapies to address the unmet needs for additional renal protective strategies. The ability to noninvasively image the molecular and cellular processes that underlie diabetic nephropathy would be useful in risk stratifying patients with diabetes, and more importantly would aid in the evaluation of novel therapies to prevent and treat nephropathy. In addition, the development of ultrasound technologies that allow targeted gene delivery using high-power ultrasound and DNA-bearing microbubbles may have applicability for gene therapy to prevent diabetic nephropathy. This review highlights contrast-enhanced ultrasound imaging techniques for the evaluation of renal pathologies, including perfusion and molecular imaging techniques, and ultrasound-mediated gene delivery for therapeutic applications in diabetic nephropathy, that have potential for translation to clinical practice.

HGF-mediated inhibition of oxidative stress by 8-nitro-cGMP in high glucose-treated rat mesangial cells

Hepatocyte growth factor (HGF) is a potential therapeutic agent for diabetic nephropathy. The mechanisms for the renoprotective effect of HGF have been studied extensively, but antioxidant signalling of HGF in diabetic nephropathy is minimally understood. Our observations indicated that a nitrated guanine nucleotide, 8-nitroguanosine 3'5'-cyclic monophosphate (8-nitro-cGMP) diminished in high glucose (HG)-treated rat mesangial cells (RMC). However, HGF obviously lifted intracellular 8-nitro-cGMP level, which was accompanied by remarkably suppressed oxidative stress as evidenced by decreased reactive oxygen species and malondialdehyde levels and elevated glutathione level. Inhibitor of soluble guanylyl cyclase (sGC) NS-2028 and inhibitor of nitric oxide synthase (NOS) l-NMMA could block increased 8-nitro-cGMP level and repress oxidative stress by HGF. Accordingly, these two inhibitors abrogated HGF-induced nuclear accumulation of NF-E2 related factor 2 (Nrf2) and up-regulation of Nrf2 downstream glutamate-cysteine ligase catalytic subunit (GCLC) expression. In conclusion, HGF ameliorated HG-mediated oxidative stress in RMC at least in part by enhancing nitric oxide and subsequent 8-nitro-cGMP production.

Pathophysiological changes to the peritoneal membrane during PD-related peritonitis: the role of mesothelial cells

The success of peritoneal dialysis (PD) is dependent on the structural and functional integrity of the peritoneal membrane. The mesothelium lines the peritoneal membrane and is the first line of defense against chemical and/or bacterial insult. Peritonitis remains a major complication of PD and is a predominant cause of technique failure, morbidity and mortality amongst PD patients. With appropriate antibiotic treatment, peritonitis resolves without further complications, but in some PD patients excessive peritoneal inflammatory responses lead to mesothelial cell exfoliation and thickening of the submesothelium, resulting in peritoneal fibrosis and sclerosis. The detrimental changes in the peritoneal membrane structure and function correlate with the number and severity of peritonitis episodes and the need for catheter removal. There is evidence that despite clinical resolution of peritonitis, increased levels of inflammatory and fibrotic mediators may persist in the peritoneal cavity, signifying persistent injury to the mesothelial cells. This review will describe the structural and functional changes that occur in the peritoneal membrane during peritonitis and how mesothelial cells contribute to these changes and respond to infection. The latter part of the review discusses the potential of mesothelial cell transplantation and genetic manipulation in the preservation of the peritoneal membrane.

Preservations of nephrin and synaptopodin by recombinant hepatocyte growth factor in podocytes for the attenuations of foot process injury and albuminuria in nephritic mice

AIM

Podocytes provide a slit diaphragm to inhibit proteinuria, and nephrin between podocytes functions as a barrier during glomerular filtration. Hepatocyte growth factor (HGF) can improve proteinuria in rodents with various renal injuries, but little is known about the role of HGF in podocyte-based events during glomerulonephritis. In the present study, we examined whether and how nephrin expression is sustained by podocytes during the HGF-mediated attenuation of albuminuria.

METHODS

Lipopolysaccharide (LPS)-treated mice were used as an animal model of albuminuria. We evaluated the effect of HGF on slit proteins using immunohistochemistry, western blotting and real-time polymerase chain reaction.

RESULTS

Albuminuria occurred 36 h after LPS treatment in mice. This albuminuria did not involve podocyte loss, but was associated with a decrease in nephrin and its key anchor, synaptopodin. In these processes, c-Met tyrosine phosphorylation, which represented HGF signal activation, occurred in glomerular cells including podocytes. When recombinant HGF was administrated to nephritic mice, c-Met tyrosine phosphorylation became evident in podocytes. The enhancement of the HGF-c-Met signal was associated with increases in nephrin and synaptopodin. An electron microscopic examination revealed that LPS induced the foot process effacement of podocytes, while HGF injections suppressed the foot process injury. Overall, albuminuria was attenuated in the LPS-treated mice after HGF administration.

CONCLUSION

HGF protects podocytes from a loss of nephrin, at least in part, through maintaining synaptopodin. As a result, HGF was shown to sustain foot process structure, and albuminuria was attenuated under inflammation.

Leptin gene therapy in the fight against diabetes

IMPORTANCE OF THE FIELD

The incidence of diabetes is increasing worldwide, yet current treatments are not always effective for all patient or disease types.

AREAS COVERED IN THIS REVIEW

Here, we summarize the biologic and clinical roles of leptin in diabetes, and discuss candidate viral vectors that may be employed in the clinical use of central leptin gene therapy for diabetes.

WHAT THE READER WILL GAIN

We discuss how studies on leptin, a regulator of the insulin-glucose axis, have significantly advanced our understanding of the roles of energy homeostasis and insulin resistance in the pathogeneses of metabolic syndrome and diabetes. Recent studies have demonstrated the long-term therapeutic effects of central leptin gene therapy in obesity and diabetes via decreased insulin resistance and increased glucose metabolism. Many of these studies have employed viral vectors, which afford high in vivo gene transduction efficiencies compared with non-viral vectors.

TAKE HOME MESSAGE

Adeno-associated viral vectors are particularly well suited for central leptin gene therapy owing to their low toxicity and ability to drive transgene expression for extended periods.

Mesenchymal stem cells attenuate renal fibrosis through immune modulation and remodeling properties in a rat remnant kidney model

Mesenchymal stem cells (MSCs) have regenerative properties in acute kidney injury, but their role in chronic kidney diseases is still unknown. More specifically, it is not known whether MSCs halt fibrosis. The purpose of this work was to investigate the role of MSCs in fibrogenesis using a model of chronic renal failure. MSCs were obtained from the tibias and femurs of male Wistar-EPM rats. Female Wistar rats were subjected to the remnant model, and 2|x|10(5) MSCs were intravenously administrated to each rat every other week for 8 weeks or only once and followed for 12 weeks. SRY gene expression was observed in female rats treated with male MSCs, and immune localization of CD73(+)CD90(+) cells at 8 weeks was also assessed. Serum and urine analyses showed an amelioration of functional parameters in MSC-treated animals at 8 weeks, but not at 12 weeks. Masson's trichrome and Sirius red staining demonstrated reduced levels of fibrosis in MSC-treated animals. These results were corroborated by reduced vimentin, type I collagen, transforming growth factor beta, fibroblast specific protein 1 (FSP-1), monocyte chemoattractant protein 1, and Smad3 mRNA expression and alpha smooth muscle actin and FSP-1 protein expression. Renal interleukin (IL)-6 and tumor necrosis factor alpha mRNA expression levels were significantly decreased after MSC treatment, whereas IL-4 and IL-10 expression levels were increased. All serum cytokine expression levels were decreased in MSC-treated animals. Taken together, these results suggested that MSC therapy can indeed modulate the inflammatory response that follows the initial phase of a chronic renal injury. The immunosuppressive and remodeling properties of MSCs may be involved in the decreased fibrosis in the kidney.

Scatter Factors in renal disease: Dr. Jeckyll and Mr. Hyde?

The Scatter Factors are two homologous proteins, named Scatter Factor/Hepatocyte Growth Factor and Macrophage Stimulating Protein. Their receptors are the products of two oncogenes, Met and Ron, respectively. The Scatter Factors induce movement, stimulate proliferation, regulate apoptosis and are morphogenic, i.e. operate an integrated program that seems tailored to drive organ development and to regenerate injured tissues. On the other hand, Scatter Factors may be responsible for pathologic tissue remodeling, infiltration of inflammatory cells, and tumor growth and diffusion. The review describes the involvement of Scatter Factors in renal disease, including acute renal failure, glomerulonephritis, chronic fibrosing nephropathies, dialysis, renal transplantation and renal tumors, and discusses the double-faced role of Scatter Factors, that play either a protective or a pathogenic role.

Intestinal fibrosis in inflammatory bowel disease - Current knowledge and future perspectives

BACKGROUND AND AIMS

Intestinal fibrosis is a common complication of IBD that can become seriously symptomatic and may require surgical intervention if stricture formation ensues. This review discusses existing and developing knowledge of intestinal fibrosis and its implications for therapy.

METHODS

Review of the literature, personal communications, unpublished observations.

RESULTS

Known mechanisms of intestinal fibrosis include fibroblast proliferation and migration, activation of stellate cells, and extraintestinal fibroblast recruitment. However, novel mechanisms are being uncovered, including epithelial-to-mesenchymal transition, endothelial-to-mesenchymal transition, pericyte differentiation, and fibrocyte recruitment. Most of the traditional and novel mechanisms underlying intestinal fibrosis are associated to the presence of chronic inflammation, but is also possible that fibrosis develops independently of persistent immune activation in the gut. At the moment, the development of preventive, non-interventional, and more effective management of intestinal fibrosis is hampered by the lack of a greater knowledge of its basic pathophysiology and predisposing factors.

CONCLUSIONS

It is reasonable to expect that therapy of IBD-associated fibrosis will radically improve once the underlying mechanisms are better understood, and therapeutic modalities will emerge that prevent or reverse this complication of IBD.

The therapeutic potential of hepatocyte growth factor to sensitize ovarian cancer cells to cisplatin and paclitaxel in vivo

PURPOSE

Advanced ovarian cancers are initially responsive to combinatorial chemotherapy with platinum drugs and taxanes but, in most cases, develop drug resistance. We recently showed that, in vitro, hepatocyte growth factor (HGF) enhances death of human ovarian cancer cell lines treated with cisplatin (CDDP) and paclitaxel. The present study addresses whether in vivo HGF makes ovarian carcinoma cells more responsive to these chemotherapeutics.

EXPERIMENTAL DESIGN

Using Lentiviral vectors carrying the HGF transgene, we transduced SK-OV-3 and NIH:OVCAR-3 ovarian carcinoma cell lines to obtain stable autocrine and paracrine HGF receptor activation. In vitro, we assayed growth, motility, invasiveness, and the response to CDDP and paclitaxel of the HGF-secreting bulk unselected cell populations. In vivo, we tested the cytotoxic effects of the drugs versus s.c. tumors formed by the wild-type and HGF-secreting cells in immunocompromised mice. Tumor-bearing mice were treated with CDDP (i.p.) and paclitaxel (i.v.), combined in different schedules and doses.

RESULTS

In vitro, HGF-secreting cells did not show altered proliferation rates and survival but were strongly sensitized to the death triggered by CDDP and paclitaxel, alone or in combination. In vivo, we found a therapeutic window in which autocrine/paracrine HGF made tumors sensitive to low doses of the drugs, which were ineffective on their own.

CONCLUSIONS

These data provide the proof-of-concept that in vivo gene therapy with HGF might be competent in sensitizing ovarian cancer cells to conventional chemotherapy.

Phenotypic transitions and fibrosis in diabetic nephropathy

The cause of renal fibrosis in diabetic nephropathy is widely believed to be phenotypic switching of fibroblasts to an activated state. However, emerging evidence suggests that diabetes also alters the phenotype of normal, non-fibroblast kidney cells, such as mesangial cells, tubular epithelial cells, and bone marrow-derived progenitors. Experiments have shown that cytokines, high glucose, and advanced glycation end products induce profibrotic changes in kidney cell phenotype by the processes of myofibroblast transdifferentiation and epithelial-mesenchymal transition. As a result, differentiated kidney cells become reprogrammed to secrete and accumulate extracellular matrix. This revised view implies that inhibiting phenotypic transitions in nonfibroblasts might limit fibrosis in diabetic nephropathy.

HGF protects rat mesangial cells from high-glucose-mediated oxidative stress

BACKGROUND

Oxidative stress has been considered to be a common pathogenetic factor of diabetic nephropathy. Recent observations suggested that hepatocyte growth factor (HGF) was an antioxidant growth factor; thus, its renoprotective effects in diabetic nephropathy might be related to antioxidant mechanism. The aim of the present study was to evaluate whether HGF could prevent rat mesangial cells (RMC) from high-glucose-mediated oxidative stress and explore its relevant mechanism.

METHODS

RMC were cultured in 5.6 mM (NG) or 30 mM (HG) glucose in the absence or presence of HGF (20 ng/ml) and c-met inhibitor SU11274 (5 microM) for 24 h.

RESULTS

c-met expression in HG was markedly increased. Enhanced oxidative stress was observed in HG as evidenced by elevated reactive oxygen species and malondialdehyde levels and decreased glutathione level, which was markedly attenuated by HGF. HGF also inhibited HG-induced p22(phox) and aldose reductase upregulation and prevented HG-reduced glutamate-cysteine ligase catalytic subunit (GCLC) expression through inhibiting USF binding to negative regulatory region of GCLC promoter. Reduced glucose-6-phosphate dehydrogenase activity and expression in RMC by HG was rescued by HGF.

CONCLUSION

HGF could function as an antioxidant factor and protect against HG-mediated oxidative stress by enhancing ROS scavenging and suppressing ROS production.