Hepatocyte growth factor prevents acute renal failure and accelerates renal regeneration in mice

Blood flow-induced angiocrine signals promote organ growth and regeneration

Recently, we identified myeloid-derived growth factor (MYDGF) as a blood flow-induced angiocrine signal that promotes human and mouse hepatocyte proliferation and survival. Here, we review literature reporting changes in blood flow after partial organ resection in the liver, lung, and kidney, and we describe the angiocrine signals released by endothelial cells (ECs) upon blood flow alterations in these organs. While hepatocyte growth factor (HGF) and MYDGF are important angiocrine signals for liver regeneration, by now, angiocrine signals have also been reported to stimulate hyperplasia and/or hypertrophy during the regeneration of lungs and kidneys. In addition, angiocrine signals play a critical role in tumor growth. Understanding the mechano-elastic properties and flow-mediated alterations in the organ-specific microvasculature is crucial for therapeutic approaches to maintain organ health and initiate organ renewal.

MET Activation in Lung Cancer and Response to Targeted Therapies

The hepatocyte growth factor receptor (MET) is a receptor tyrosine kinase (RTK) that mediates the activity of a variety of downstream pathways upon its activation. These pathways regulate various physiological processes within the cell, including growth, survival, proliferation, and motility. Under normal physiological conditions, this allows MET to regulate various development and regenerative processes; however, mutations resulting in aberrant MET activity and the consequent dysregulation of downstream signaling can contribute to cellular pathophysiology. Mutations within MET have been identified in a variety of cancers and have been shown to mediate tumorigenesis by increasing RTK activity and downstream signaling. In lung cancer specifically, a number of patients have been identified as possessing MET alterations, commonly receptor amplification (METamp) or splice site mutations resulting in loss of exon 14 (METex14). Due to MET's role in mediating oncogenesis, it has become an attractive clinical target and has led to the development of various targeted therapies, including MET tyrosine kinase inhibitors (TKIs). Unfortunately, these TKIs have demonstrated limited clinical efficacy, as patients often present with either primary or acquired resistance to these therapies. Mechanisms of resistance vary but often occur through off-target or bypass mechanisms that render downstream signaling pathways insensitive to MET inhibition. This review provides an overview of the therapeutic landscape for MET-positive cancers and explores the various mechanisms that contribute to therapeutic resistance in these cases.

Adverse effects of graft congestion and ameliorative effects of hepatocyte growth factor after liver transplantation in rats

Living donor liver transplantation (LT) and deceased donor split-LT often result in congestion within liver grafts. The regenerative process and function of congested areas, especially graft congestion associated with LT, are not well understood. Therefore, we created new rat models with congested areas in partially resected livers and orthotopically transplanted these livers into syngeneic rats to observe liver regeneration and function in congested areas. This study aimed to compare liver regeneration and the function of congested areas after liver resection and LT, and to explore a new approach to ameliorate the adverse effects of graft congestion. Although the congested areas after liver resection regenerated normally on postoperative day 7, the congested areas after LT had poor regeneration with abscess development on postoperative day 7. Necrotic areas in congested areas were larger after LT than after liver resection on postoperative days 1, 3, and 7 ( p < 0.05, p < 0.05, and p < 0.01, respectively). Although congested areas after liver resection did not affect survival, in the LT model, the survival of rats with congested areas was significantly poorer even with larger grafts than that of rats with smaller noncongested grafts ( p = 0.04). Hepatocyte growth factor administration improved the survival rate of rats with congested grafts from 41.7% to 100%, improved the regeneration of congested areas, and significantly reduced the size of necrotic areas ( p < 0.05). Thus, congested areas in liver grafts may negatively impact recipients. Short-term administration of hepatocyte growth factor may improve postoperative outcomes of recipients with graft congestion and contribute to more effective use of liver grafts (approval number: MedKyo-23137, Institutional Ethics Committee/Kyoto University).

New drugs for acute kidney injury

Acute kidney injury (AKI) presents a significant challenge in the management of critically ill patients, as it is associated with increased mortality, prolonged hospital stays, and increased healthcare costs. In certain conditions, such as during sepsis or after cardiac surgery, AKI is one of the most frequent complications, affecting 30%-50% of patients. Over time, even after the resolution of AKI, it can evolve into chronic kidney disease, a leading global cause of mortality, and cardiovascular complications. Despite significant improvement in the care of critically ill patients over the past two decades, the incidence of AKI remains stable, and novel approaches aiming at reducing its occurrence or improving AKI outcomes are still mostly lacking. However, recent insights into the pathophysiology of AKI within critical care settings have shed light on new pathways for both prevention and treatment, providing various new therapeutic targets aimed to mitigating kidney injury. These advancements highlight the intricate and multifaceted nature of the mechanisms underlying AKI, which could explain the challenge of identifying an effective treatment. Among these targets, modulation of the inflammatory responses and the cellular metabolism, hemodynamic regulation and enhancement of cellular repair mechanisms, have emerged as promising options. These multifaceted approaches offer renewed hope for limiting the incidence and severity of AKI in critically ill patients. Several ongoing clinical trials are evaluating the efficacy of these different strategies and we are facing an exiting time with multiple therapeutic interventions being tested to prevent or treat AKI. In this review, we aim to provide a summary of the new drugs evaluated for preventing or treating AKI in critical care and surgical settings.

Development of and recovery from acute kidney injury after cardiac surgery: Randomized phase 2 trial of the hepatocyte growth factor mimetic ANG-3777

OBJECTIVES

To investigate the safety and efficacy of ANG-3777, a hepatocyte growth factor mimetic, in mitigating the risk of acute kidney injury (AKI) in patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

In this double-blind placebo-controlled study (Guard Against Renal Damage [GUARD]), patients were randomized to receive intravenous ANG-3777 2 mg/kg or placebo once daily for 4 days. The primary end point was severity of AKI, measured by mean area under the concentration-time curve on percent increase in serum creatinine from days 2 to 6. Secondary end points included the proportions of patients who developed major adverse kidney events by day 30 or 90 and the percentage of patients diagnosed with AKI through day 5.

RESULTS

In total, 259 patients received study treatment (ANG-3777, n = 129; placebo, n = 130). Through day 6, there was no significant difference in least-squares mean change in serum creatinine between ANG-3777 and placebo (1.1%; 95% confidence interval, -6.2 to 8.4; P = .77), or in proportions of patients who developed major adverse kidney events by day 30 (18.6% vs 16.2%; P = .60) or day 90 (14.7% vs 21.5%; P = .16). Similar proportions of patients were diagnosed with AKI through day 5 (ANG-3777, 47.3%; placebo, 48.5%); however, exploratory analysis revealed more patients diagnosed with AKI postoperatively showed signs of recovery after treatment with ANG-3777 than placebo. Overall, ANG-3777 was well tolerated, with similar incidences of treatment-emergent adverse events between treatment arms.

CONCLUSIONS

Findings from this study do not support the efficacy of ANG-3777 in preventing the development of AKI after cardiopulmonary bypass.

In vitro immuno-prevention of nitration/dysfunction of myogenic stem cell activator HGF, towards developing a strategy for age-related muscle atrophy

In response to peroxynitrite (ONOO-) generation, myogenic stem satellite cell activator HGF (hepatocyte growth factor) undergoes nitration of tyrosine residues (Y198 and Y250) predominantly on fast IIa and IIx myofibers to lose its binding to the signaling receptor c-met, thereby disturbing muscle homeostasis during aging. Here we show that rat anti-HGF monoclonal antibody (mAb) 1H41C10, which was raised in-house against a synthetic peptide FTSNPEVRnitroY198EV, a site well-conserved in mammals, functions to confer resistance to nitration dysfunction on HGF. 1H41C10 was characterized by recognizing both nitrated and non-nitrated HGF with different affinities as revealed by Western blotting, indicating that the paratope of 1H41C10 may bind to the immediate vicinity of Y198. Subsequent experiments showed that 1H41C10-bound HGF resists peroxynitrite-induced nitration of Y198. A companion mAb-1H42F4 presented similar immuno-reactivity, but did not protect Y198 nitration, and thus served as the control. Importantly, 1H41C10-HGF also withstood Y250 nitration to retain c-met binding and satellite cell activation functions in culture. The Fab region of 1H41C10 exerts resistivity to Y250 nitration possibly due to its localization in the immediate vicinity to Y250, as supported by an additional set of experiments showing that the 1H41C10-Fab confers Y250-nitration resistance which the Fc segment does not. Findings highlight the in vitro preventive impact of 1H41C10 on HGF nitration-dysfunction that strongly impairs myogenic stem cell dynamics, potentially pioneering cogent strategies for counteracting or treating age-related muscle atrophy with fibrosis (including sarcopenia and frailty) and the therapeutic application of investigational HGF drugs.

Gemcitabine-Phospholipid Complex Loaded Lipid Nanoparticles for Improving Drug Loading, Stability, and Efficacy against Pancreatic Cancer

This study aims to encapsulate gemcitabine (GEM) using a phospholipid complex (PLC) in lipid nanoparticles (NPs) to achieve several desirable outcomes, including high drug loading, uniform particle size, improved therapeutic efficacy, and reduced toxicities. The successful preparation of GEM-loaded lipid NPs (GEM-NPs) was accomplished using the emulsification-solidification method, following optimization through Box-Behnken design. The size of the GEM-NP was 138.5 ± 6.7 nm, with a low polydispersity index of 0.282 ± 0.078, as measured by a zetasizer and confirmed by transmission electron and atomic force microscopy. GEM-NPs demonstrated sustained release behavior, surpassing the performance of the free GEM and phospholipid complex. Moreover, GEM-NPs exhibited enhanced cytotoxicity, apoptosis, and cell uptake in Panc-2 and Mia PaCa cells compared to the free GEM. The in vivo pharmacokinetics revealed approximately 4-fold higher bioavailability of GEM-NPs in comparison with free GEM. Additionally, the pharmacodynamic evaluation conducted in a DMBA-induced pancreatic cancer model, involving histological examination, serum IL-6 level estimation, and expression of cleaved caspase-3, showed the potential of GEM-NPs in the management of pancreatic cancer. Consequently, the lipid NP-based approach developed in our investigation demonstrates high stability and uniformity and holds promise for enhancing the therapeutic outcomes of GEM.

Advances in pediatric acute kidney injury pathobiology: a report from the 26th Acute Disease Quality Initiative (ADQI) conference

BACKGROUND

In the past decade, there have been substantial advances in our understanding of the pathobiology of pediatric acute kidney injury (AKI). In particular, animal models and studies focused on the relationship between kidney development, nephron number, and kidney health have identified a number of heterogeneous pathophysiologies underlying AKI. Despite this progress, gaps remain in our understanding of the pathobiology of pediatric AKI.

METHODS

During the 26th Acute Disease Quality Initiative (ADQI) Consensus conference, a multidisciplinary group of experts discussed the evidence and used a modified Delphi process to achieve consensus on recommendations for opportunities to advance translational research in pediatric AKI. The current state of research understanding as well as gaps and opportunities for advancement in research was discussed, and recommendations were summarized.

RESULTS

Consensus was reached that to improve translational pediatric AKI advancements, diverse teams spanning pre-clinical to epidemiological scientists must work in concert together and that results must be shared with the community we serve with patient involvement. Public and private research support and meaningful partnerships with adult research efforts are required. Particular focus is warranted to investigate the pediatric nuances of AKI, including the effect of development as a biological variable on AKI incidence, severity, and outcomes.

CONCLUSIONS

Although AKI is common and associated with significant morbidity, the biologic basis of the disease spectrum throughout varying nephron developmental stages remains poorly understood. An incomplete understanding of factors contributing to kidney health, the diverse pathobiologies underlying AKI in children, and the historically siloed approach to research limit advances in the field. The recommendations outlined herein identify gaps and outline a strategic approach to advance the field of pediatric AKI via multidisciplinary translational research.

Age-related nitration/dysfunction of myogenic stem cell activator HGF

Mechanical perturbation triggers activation of resident myogenic stem cells to enter the cell cycle through a cascade of events including hepatocyte growth factor (HGF) release from its extracellular tethering and the subsequent presentation to signaling-receptor c-met. Here, we show that with aging, extracellular HGF undergoes tyrosine-residue (Y) nitration and loses c-met binding, thereby disturbing muscle homeostasis. Biochemical studies demonstrated that nitration/dysfunction is specific to HGF among other major growth factors and is characterized by its locations at Y198 and Y250 in c-met-binding domains. Direct-immunofluorescence microscopy of lower hind limb muscles from three age groups of rat, provided direct in vivo evidence for age-related increases in nitration of ECM-bound HGF, preferentially stained for anti-nitrated Y198 and Y250-HGF mAbs (raised in-house) in fast IIa and IIx myofibers. Overall, findings highlight inhibitory impacts of HGF nitration on myogenic stem cell dynamics, pioneering a cogent discussion for better understanding age-related muscle atrophy and impaired regeneration with fibrosis (including sarcopenia and frailty).

Development of multifunctional pyrrole-imidazole polyamides that increase hepatocyte growth factor and suppress transforming growth factor-β1

PURPOSE

The DNA recognition peptide compounds pyrrole-imidazole (PI) polyamides bind to the minor groove and can block the binding of transcription factors to target sequences. To develop more PI polyamides as potential treatments for fibrotic diseases, including chronic renal failure, we developed multifunctional PI polyamides that increase hepatocyte growth factor (HGF) and decrease transforming growth factor (TGF)-β1.

METHODS

We designed seven PI polyamides (HGF-1 to HGF-7) that bind to the chicken ovalbumin upstream promoter transcription factor-1 (COUP-TF1) binding site of the HGF promoter sequence. We selected PI polyamides that increase HGF and suppress TGF-β1 in human dermal fibroblasts (HDFs).

FINDINGS

Gel shift assays showed that HGF-2 and HGF-4 bound the appropriate dsDNAs. HGF-2 and HGF-4 significantly inhibited the TGF-β1 mRNA expression in HDFs stimulated by phorbol 12-myristate 13-acetate. HGF-2 and HGF-4 significantly inhibited the TGF-β1 protein expression in HDFs with siRNA targeting HGF, indicating that HGF-2 and HGF-4 directly inhibited the expression of TGF-β1.

CONCLUSION

The designed and synthetic HGF PI polyamides targeting the HGF promoter, which increased the expression of HGF and suppressed the expression of TGF-β, will be a potential practical medicine for fibrotic diseases, including progressive renal diseases.

Identifying Dental Pulp Stem Cell as a Novel Therapeutic trategy for Digestive Diseases

Mesenchymal stem cells (MSCs) have been identified as potential therapeutics for various diseases. In contrast to other sources of MSCs, dental stem cells (DSCs) have received increased attention due to their high activity and easy accessibility. Among them, dental pulp stem cells (DPSCs) exhibit superior self-renewal, multipotency, immunomodulatory, and regenerative capacities. Following their inspiring performance in animal models and clinical trials, DPSCs show pharmacological potential in regenerative medicine. In this review, we have generalized the sources, heterogeneity, and biological characteristics of DPSCs, as well as compared them with other types of dental stem cells. In addition, we summarized the application of DPSCs in digestive diseases (such as liver, esophageal, and intestinal diseases), highlighting their regenerative and pharmacological potential based on the existing preclinical and clinical evidence. Specifically, DPSCs can be home to injured or inflamed tissues and exert repair and regeneration functions by facilitating immune regulation, anti-inflammation, and directional differentiation. Although DPSCs have a rosy prospect, future studies should handle the underlying drawbacks and pave the way for the identification of DPSCs as novel regenerative medicine.

Hepatocyte transplantation: The progress and the challenges

Numerous studies have shown that hepatocyte transplantation is a promising approach for liver diseases, such as liver-based metabolic diseases and acute liver failure. However, it lacks strong evidence to support the long-term therapeutic effects of hepatocyte transplantation in clinical practice. Currently, major hurdles include availability of quality-assured hepatocytes, efficient engraftment and repopulation, and effective immunosuppressive regimens. Notably, cell sources have been advanced recently by expanding primary human hepatocytes by means of dedifferentiation in vitro. Moreover, the transplantation efficiency was remarkably improved by the established preparative hepatic irradiation in combination with hepatic mitogenic stimuli regimens. Finally, immunosuppression drugs, including glucocorticoid and inhibitors for co-stimulating signals of T cell activation, were proposed to prevent innate and adaptive immune rejection of allografted hepatocytes. Despite remarkable progress, further studies are required to improve in vitro cell expansion technology, develop clinically feasible preconditioning regimens, and further optimize immunosuppression regimens or establish ex vivo gene correction-based autologous hepatocyte transplantation.

Guiding Hepatic Differentiation of Pluripotent Stem Cells Using 3D Microfluidic Co-Cultures with Human Hepatocytes

Human pluripotent stem cells (hPSCs) are capable of unlimited proliferation and can undergo differentiation to give rise to cells and tissues of the three primary germ layers. While directing lineage selection of hPSCs has been an active area of research, improving the efficiency of differentiation remains an important objective. In this study, we describe a two-compartment microfluidic device for co-cultivation of adult human hepatocytes and stem cells. Both cell types were cultured in a 3D or spheroid format. Adult hepatocytes remained highly functional in the microfluidic device over the course of 4 weeks and served as a source of instructive paracrine cues to drive hepatic differentiation of stem cells cultured in the neighboring compartment. The differentiation of stem cells was more pronounced in microfluidic co-cultures compared to a standard hepatic differentiation protocol. In addition to improving stem cell differentiation outcomes, the microfluidic co-culture system described here may be used for parsing signals and mechanisms controlling hepatic cell fate.

The Transfer of the Hepatocyte Growth Factor Gene by Macrophages Ameliorates the Progression of Peritoneal Fibrosis in Mice

Growing evidence indicates that hepatocyte growth factor (HGF) possesses potent antifibrotic activity. Furthermore, macrophages migrate to inflamed sites and have been linked to the progression of fibrosis. In this study, we utilized macrophages as vehicles to express and deliver the HGF gene and investigated whether macrophages carrying the HGF expression vector (HGF-M) could suppress peritoneal fibrosis development in mice. We obtained macrophages from the peritoneal cavity of mice stimulated with 3% thioglycollate and used cationized gelatin microspheres (CGMs) to produce HGF expression vector-gelatin complexes. Macrophages phagocytosed these CGMs, and gene transfer into macrophages was confirmed in vitro. Peritoneal fibrosis was induced by intraperitoneal injection of chlorhexidine gluconate (CG) for three weeks; seven days after the first CG injection, HGF-M was administered intravenously. Transplantation of HGF-M significantly suppressed submesothelial thickening and reduced type III collagen expression. Moreover, in the HGF-M-treated group, the number of α-smooth muscle actin- and TGF-β-positive cells were significantly lower in the peritoneum, and ultrafiltration was preserved. Our results indicated that the transplantation of HGF-M prevented the progression of peritoneal fibrosis and indicated that this novel gene therapy using macrophages may have potential for treating peritoneal fibrosis.

Rapid and effective preparation of clonal bone marrow-derived mesenchymal stem/stromal cell sheets to reduce renal fibrosis

Allogeneic "off-the-shelf" mesenchymal stem/stromal cell (MSC) therapy requires scalable, quality-controlled cell manufacturing and distribution systems to provide clinical-grade products using cryogenic cell banking. However, previous studies report impaired cell function associated with administering freeze-thawed MSCs as single cell suspensions, potentially compromising reliable therapeutic efficacy. Using long-term culture-adapted clinical-grade clonal human bone marrow MSCs (cBMSCs) in this study, we engineered cBMSC sheets in 24 h to provide rapid preparation. We then sought to determine the influence of cBMSC freeze-thawing on both in vitro production of pro-regenerative factors and in vivo ability to reduce renal fibrosis in a rat model compared to freshly harvested cBMSCs. Sheets from freeze-thawed cBMSCs sheets exhibited comparable in vitro protein production and gene expression of pro-regenerative factors [e.g., hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), and interleukin 10 (IL-10)] to freshly harvested cBMSC sheets. Additionally, freeze-thawed cBMSC sheets successfully suppressed renal fibrosis in vivo in an established rat ischemia-reperfusion injury model. Despite previous studies reporting that freeze-thawed MSCs exhibit impaired cell functions compared to fresh MSC single cell suspensions, cell sheets engineered from freeze-thawed cBMSCs do not exhibit impaired cell functions, supporting critical steps toward future clinical translation of cBMSC-based kidney disease treatment.

Hirsutidin Prevents Cisplatin-Evoked Renal Toxicity by Reducing Oxidative Stress/Inflammation and Restoring the Endogenous Enzymatic and Non-Enzymatic Level

Recent research has shown that phytocomponents may be useful in the treatment of renal toxicity. This study was conducted to evaluate the renal disease hirsutidin in the paradigm of renal toxicity induced by cisplatin. Male Wistar rats were given cisplatin (3 mg/kg body weight/day, for 25 days, i.p.) to induce renal toxicity. Experimental rats were randomly allocated to four different groups: group I received saline, group II received cisplatin, group III received cisplatin + hirsutidin (10 mg/kg)and group IV (per se)received hirsutidin (10 m/kg)for 25 days. Various biochemical parameters were assessed, oxidative stress (superoxide dismutase (SOD), glutathione transferase (GSH), malonaldehyde (MDA) and catalase (CAT)), blood-chemistry parameters (blood urea nitrogen (BUN) and cholesterol), non-protein-nitrogenous components (uric acid, urea, and creatinine), and anti-inflammatory-tumor necrosis factor-α (TNF-α), interleukin-1β(IL-1β). IL-6 and nuclear factor-kB (NFκB) were evaluated and histopathology was conducted. Hirsutidin alleviated renal injury which was manifested by significantly diminished uric acid, urea, urine volume, creatinine, and BUN, compared to the cisplatin group. Hirsutidin restored the activities of several antioxidant enzyme parameters—MDA, CAT, GSH, and SOD. Additionally, there was a decline in the levels of inflammatory markers—TNF-α, IL-1β, IL-6, and NFκB—compared to the cisplatin group. The current research study shows that hirsutidin may act as a therapeutic agent for the treatment of nephrotoxicity induced by cisplatin.

Impact of Nanotechnology on Differentiation and Augmentation of Stem Cells for Liver Therapy

The liver is one of the crucial organs of the body that performs hundreds of chemical reactions needed by the body to survive. It is also the largest gland of the body. The liver has multiple functions, including the synthesis of chemicals, metabolism of nutrients, and removal of toxins. It also acts as a storage unit. The liver has a unique ability to regenerate itself, but it can lead to permanent damage if the injury is beyond recovery. The only possible treatment of severe liver damage is liver transplant which is a costly procedure and has several other drawbacks. Therefore, attention has been shifted towards the use of stem cells that have shown the ability to differentiate into hepatocytes. Among the numerous kinds of stem cells (SCs), the mesenchymal stem cells (MSCs) are the most famous. Various studies suggest that an MSC transplant can repair liver function, improve the signs and symptoms, and increase the chances of survival. This review discusses the impact of combining stem cell therapy with nanotechnology. By integrating stem cell science and nanotechnology, the information about stem cell differentiation and regulation will increase, resulting in a better comprehension of stem cell-based treatment strategies. The augmentation of SCs with nanoparticles has been shown to boost the effect of stem cell-based therapy. Also, the function of green nanoparticles in liver therapies is discussed.

Targeting c-Met in the treatment of urologic neoplasms: Current status and challenges

At present, studies have found that c-Met is mainly involved in epithelial-mesenchymal transition (EMT) of tumor tissues in urologic neoplasms. Hepatocyte growth factor (HGF) combined with c-Met promotes the mitosis of tumor cells, and then induces motility, angiogenesis, migration, invasion and drug resistance. Therefore, c-Met targeting therapy may have great potential in urologic neoplasms. Many strategies targeting c-Met have been widely used in the study of urologic neoplasms. Although the use of targeting c-Met therapy has a strong biological basis for the treatment of urologic neoplasms, the results of current clinical trials have not yielded significant results. To promote the application of c-Met targeting drugs in the clinical treatment of urologic neoplasms, it is very important to study the detailed mechanism of c-Met in urologic neoplasms and innovate c-Met targeted drugs. This paper firstly discussed the value of c-Met targeted therapy in urologic neoplasms, then summarized the related research progress, and finally explored the potential targets related to the HGF/c-Met signaling pathway. It may provide a new concept for the treatment of middle and late urologic neoplasms.

An agonistic monoclonal antibody targeting cMet attenuates inflammation and upregulates collagen synthesis and angiogenesis in Type 2 diabetic mouse wounds

BACKGROUND

Diabetic wounds account for 25%-50% of total diabetic healthcare costs annually, and present overall healing rates of less than 50%. Since delayed diabetic wound healing is associated with impaired fibroblast function, we hypothesize that tyrosine kinase Met (cMet) agonistic monoclonal antibody (mAb) will promote diabetic wound healing via stable activation of HGF/cMet signaling.

METHODS

Two 6 mm dorsal wounds were created in each mice (6-week-old, male BKS.Cg-Dock7m+/+Leprdb/J, n=5). After subcutaneous injections of agonist (20 mg/kg) at 0 and 72h, the wound sizes were measured at days 0, 1, 3, 6, and 10. Histological and immunohistochemical analyses were performed at day 10 (cMet, α-SMA, CD68, and TGF-β). In vitro cytotoxicity and migration tests with diabetic fibroblasts were performed with/without agonist treatment (1 or 10 nM). cMet pathway activation of fibroblasts was confirmed through p-p44/42MAPK, p-mTOR, p-cMet, and ROCK-1 expression.

RESULTS

cMet agonistic mAb-treated group showed 1.60-fold lower wound area (p=0.027), 1.54-fold higher collagen synthesis (p=0.001), and 1.79-fold lower inflammatory cell infiltration (p=0.032) than the saline-treated control. The agonist increased cMet (1.86-fold, p=0.029), α-SMA (1.20-fold, p=0.018), and VEGF (1.68-fold, p=0.029) expression but suppressed CD68 (1.25-fold, p=0.043), TFG-β (1.25-fold, p=0.022), and MMP-2 (2.59-fold, p=0.029) expression. In vitro agonist treatment (10 nM) of diabetic fibroblasts increased their migration by 8.98-fold (p=0.029) and activated HGF/cMet pathway.

CONCLUSIONS

cMet agonistic mAb treatment improved diabetic wound healing in mice and reduced wound-site inflammatory cell infiltration. These results need to be validated in large animals before piloting human trials.

Decellularization of porcine kidney with submicellar concentrations of SDS results in the retention of ECM proteins required for the adhesion and maintenance of human adult renal epithelial cells

When decellularizing kidneys, it is important to maintain the integrity of the acellular extracellular matrix (ECM), including associated adhesion proteins and growth factors that allow recellularized cells to adhere and migrate according to ECM specificity. Kidney decellularization requires the ionic detergent sodium dodecyl sulfate (SDS); however, this results in a loss of ECM proteins important for cell adherence, migration, and growth, particularly glycosaminoglycan (GAG)-associated proteins. Here, we demonstrate that using submicellar concentrations of SDS results in a greater retention of structural proteins, GAGs, growth factors, and cytokines. When porcine kidney ECM scaffolds were recellularized using human adult primary renal epithelial cells (RECs), the ECM promoted cell survival and the uniform distribution of cells throughout the ECM. Cells maintained the expression of mature renal epithelial markers but did not organize on the ECM, indicating that mature cells are unable to migrate to specific locations on ECM scaffolds.

Redox nanomedicine ameliorates chronic kidney disease (CKD) by mitochondrial reconditioning in mice

Targeting reactive oxygen species (ROS) while maintaining cellular redox signaling is crucial in the development of redox medicine as the origin of several prevailing diseases including chronic kidney disease (CKD) is linked to ROS imbalance and associated mitochondrial dysfunction. Here, we have shown that a potential nanomedicine comprising of Mn3O4 nanoparticles duly functionalized with biocompatible ligand citrate (C-Mn3O4 NPs) can maintain cellular redox balance in an animal model of oxidative injury. We developed a cisplatin-induced CKD model in C57BL/6j mice with severe mitochondrial dysfunction and oxidative distress leading to the pathogenesis. Four weeks of treatment with C-Mn3O4 NPs restored renal function, preserved normal kidney architecture, ameliorated overexpression of pro-inflammatory cytokines, and arrested glomerulosclerosis and interstitial fibrosis. A detailed study involving human embryonic kidney (HEK 293) cells and isolated mitochondria from experimental animals revealed that the molecular mechanism behind the pharmacological action of the nanomedicine involves protection of structural and functional integrity of mitochondria from oxidative damage, subsequent reduction in intracellular ROS, and maintenance of cellular redox homeostasis. To the best of our knowledge, such studies that efficiently treated a multifaceted disease like CKD using a biocompatible redox nanomedicine are sparse in the literature. Successful clinical translation of this nanomedicine may open a new avenue in redox-mediated therapeutics of several other diseases (e.g., diabetic nephropathy, neurodegeneration, and cardiovascular disease) where oxidative distress plays a central role in pathogenesis.

Gene therapy for diabetic peripheral neuropathy: A randomized, placebo-controlled phase III study of VM202, a plasmid DNA encoding human hepatocyte growth factor

VM202 is a plasmid DNA encoding two isoforms of hepatocyte growth factor (HGF). A previous phase II study in subjects with painful diabetic peripheral neuropathy (DPN) showed significant reductions in pain. A phase III study was conducted to evaluate the safety and efficacy of VM202 in DPN. The trial was conducted in two parts, one for 9 months (DPN 3-1) with 500 subjects (VM202: 336 subjects; and placebo: 164) and a preplanned subset of 101 subjects (VM202: 65 subjects; and placebo: 36) with a noninterventional extension to 12 months (DPN 3-1b). VM202 or placebo was administered to calf muscles on days 0 and 14, and on days 90 and 104. The primary end point in DPN 3-1 was change from baseline in the mean 24-h Numerical Rating Scale (NRS) pain score. In DPN 3-1b, the primary end point was safety, whereas the secondary efficacy end point was change in the mean pain score. VM202 was well-tolerated in both studies without significant adverse events. VM202 failed to meet its efficacy end points in DPN 3-1. In DPN 3-1b, however, VM202 showed significant and clinically meaningful pain reduction versus placebo. Pain reduction in DPN 3-1b was even greater in subjects not receiving gabapentin or pregabalin, confirming an observation noted in the phase II study. In DPN 3-1b, symptomatic relief was maintained for 8 months after the last injection suggesting that VM202 treatment might change disease progression. Despite the perplexing discrepancy between the two studies, the safety and long-lasting pain-relieving effects of VM202 observed in DPN 3-1b warrant another rigorous phase III study. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC? Current therapies for painful diabetic peripheral neuropathy (DPN) are palliative and do not target the underlying mechanisms. Moreover, symptomatic relief is often limited with existing neuropathic pain drugs. Thus, there is a great medical need for safer and effective treatments for DPN. WHAT QUESTION DID THIS STUDY ADDRESS? Can nonviral gene delivery of hepatocyte growth factor reduce pain in patients with DPN and potentially modify progression of the disorder? WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? Nonviral gene therapy can be used safely and practically to treat DPN. HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE? As the first gene medicine to enter advanced clinical trials for the treatment of DPN, this study provides the proof of concept of an entirely new potential approach to the disorder.

Bacterial hepatocyte growth factor receptor agonist stimulates hepatocyte proliferation and accelerates liver regeneration in a partial hepatectomy rat model

Hepatocyte growth factor (HGF) is central to liver regeneration. The Internalin B (InlB) protein is a virulence factor produced by the pathogenic bacterium Listeria monocytogenes. InlB is known to mimic HGF activity by interacting with the HGF receptor (HGFR) and activating HGFR-controlled signaling pathways. We expressed and purified the HGFR-binding InlB domain, InlB321/15, cloned from the fully virulent clinical L. monocytogenes strain. HGFR and Erk1/2 phosphorylation was determined using Western blotting. The capacity of InlB321/15 to bind HGFR was measured using microscale thermophoresis. Liver regeneration was studied in a model of 70% partial hepatectomy (70%PHx) in male Wistar rats. The nuclear grade parameters were quantified using manual (percentage of binuclear hepatocytes), automated (nuclear diameters), or combined (Ki67 proliferation index) scoring methods. Purified InlB321/15 stimulated HGFR and Erk1/2 phosphorylation and accelerated the proliferation of HepG2 cells. InlB321/15 bound HGFR with Kd = 7.4 ± 1.3 nM. InlB321/15 injected intravenously on the second, fourth, and sixth days after surgery recovered the liver mass and improved the nuclear grade parameters. Seven days post 70% PHx, the liver weight indexes were 2.9 and 2.0%, the hepatocyte proliferation indexes were 19.8 and 0.6%, and the percentages of binucleated hepatocytes were 6.7 and 4.0%, in the InlB321/15-treated and control animals, respectively. Obtained data demonstrated that InlB321/15 improved hepatocyte proliferation and stimulated liver regeneration in animals with 70% hepatectomy.

Renal Function Improvement Following ANG-3777 Treatment in Patients at High Risk for Delayed Graft Function After Kidney Transplantation

BACKGROUND

Patients (20%-50%) undergoing renal transplantation experience acute kidney injury resulting in delayed graft function. ANG-3777 is an hepatocyte growth factor mimetic that binds to the c-MET receptor. In animal models, ANG-3777 decreases apoptosis, increases proliferation, and promotes organ repair and function.

METHODS

This was a randomized, double-blind, placebo-controlled, phase 2 trial of patients undergoing renal transplantation with <50 cc/h urine output for 8 consecutive hours over the first 24 hours posttransplantation, or creatinine reduction ratio <30% from pretransplantation to 24 hours posttransplantation. Subjects were randomized as 2:1 to 3, once-daily IV infusions of ANG-3777, 2 mg/kg (n = 19), or placebo (n = 9). Primary endpoint: time in days to achieve ≥1200 cc urine for 24 hours.

RESULTS

Patients treated with ANG-3777 were more likely to achieve the primary endpoint of 1200 cc urine for 24 hours by 28 days posttransplantation (83.3% versus 50% placebo; log-rank test: χ2 = 2.799, P = 0.09). Compared with placebo, patients in the ANG-3777 arm had larger increases in urine output; lower serum creatinine; greater reduction in C-reactive protein and neutrophil gelatinase-associated lipocalin; fewer dialysis sessions and shorter duration of dialysis; fewer hospital days; significantly less graft failure; and higher estimated glomerular filtration rate. Adverse events occurred in a similar percentage of subjects in both arms. Events per subject were twice as high in the placebo arm.

CONCLUSIONS

There was an efficacy signal for improved renal function in subjects treated with ANG-3777 relative to placebo, with a good safety profile.

New drugs for acute kidney injury

PURPOSE OF REVIEW

To describe recent advances in the development of therapeutic agents for acute kidney injury (AKI).

RECENT FINDINGS

Traditional care for AKI is mostly supportive. At present, no specific therapy has been developed to prevent or treat AKI. However, based on a better understanding of the pathophysiology of AKI, various potential compounds have been recently identified and tested. A variety of pathways has been targeted, including oxidative and mitochondrial stress, cellular metabolism and repair, inflammation, apoptosis and hemodynamics. Many of these potential agents are currently ongoing early-phase clinical trials, and the purpose of this review is to provide a summary of those with the most potential.

SUMMARY

Despite the lack of therapies specifically approved for AKI, many interesting potential agents are entering clinical trials, with the potential to transform the care of patients with AKI.

Mesenchymal Stem Cells as Therapeutic Agents and Novel Carriers for the Delivery of Candidate Genes in Acute Kidney Injury

Acute kidney injury (AKI) is a heterogeneous syndrome characterized by a dramatic increase in serum creatinine. Mild AKI may merely be confined to kidney damage and resolve within days; however, severe AKI commonly involves extrarenal organ dysfunction and is associated with high mortality. There is no specific pharmaceutical treatment currently available that can reverse the course of this disease. Notably, mesenchymal stem cells (MSCs) show great promise for the management of AKI by targeting multiple pathophysiological pathways to facilitate tubular epithelial cell repair. It has been well established that the unique characteristics of MSCs make them ideal vectors for gene therapy. Thus, genetic modification has been attempted to achieve improved therapeutic outcomes in the management of AKI by overexpressing trophic cytokines or facilitating MSC delivery to renal tissues. The present article provides a comprehensive review of genetic modification strategies targeted at optimizing the therapeutic potential of MSCs in AKI.

Cyclic Peptide-Based Biologics Regulating HGF-MET

Using a random non-standard peptide integrated discovery system, we obtained cyclic peptides that bind to hepatocyte growth factor (HGF) or mesenchymal-epithelial transition factor. (MET) HGF-inhibitory peptide-8 (HiP-8) selectively bound to two-chain active HGF, but not to single-chain precursor HGF. HGF showed a dynamic change in its molecular shape in atomic force microscopy, but HiP-8 inhibited dynamic change in the molecular shape into a static status. The inhibition of the molecular dynamics of HGF by HiP-8 was associated with the loss of the ability to bind MET. HiP-8 could selectively detect active HGF in cancer tissues, and active HGF probed by HiP-8 showed co-localization with activated MET. Using HiP-8, cancer tissues with active HGF could be detected by positron emission tomography. HiP-8 seems to be applicable for the diagnosis and treatment of cancers. In contrast, based on the receptor dimerization as an essential process for activation, the cross-linking of the cyclic peptides that bind to the extracellular region of MET successfully generated an artificial ligand to MET. The synthetic MET agonists activated MET and exhibited biological activities which were indistinguishable from the effects of HGF. MET agonists composed of cyclic peptides can be manufactured by chemical synthesis but not recombinant protein expression, and thus are expected to be new biologics that are applicable to therapeutics and regenerative medicine.

Hepatocyte Growth Factor Mimetic ANG-3777 for Cardiac Surgery-Associated Acute Kidney Injury

Introduction

Nearly one-third of patients undergoing cardiac surgery involving cardiopulmonary bypass (CPB) experience cardiac surgery–associated (CSA) acute kidney injury (AKI); 5% require renal replacement therapy. ANG-3777 is a hepatocyte growth factor mimetic. In vitro, ANG-3777 reduces apoptosis and increases cell proliferation, migration, morphogenesis, and angiogenesis in injured kidneys. In animal models, ANG-3777 mitigates the effects of renal damage secondary to ischemia reperfusion injury and nephrotoxic chemicals. Phase 2 data in AKI of renal transplantation have shown improved renal function and comparable safety relative to placebo. The Guard Against Renal Damage (GUARD) study is a phase 2 proof of concept trial of ANG-3777 in CSA-AKI.

Methods

GUARD is a 240-patient, multicenter, double-blind, randomized placebo-controlled trial to assess the efficacy and safety of ANG-3777 in patients at elevated pre-surgery risk for AKI undergoing coronary artery bypass graft (CABG) or heart valve repair/replacement requiring CPB. Subjects are randomized 1:1 to receive ANG-3777 (2 mg/kg) or placebo. Study drug is dosed via 4 daily intravenous 30-minute infusions. The first dose is administered less than 4 hours after completing CPB, second at 24 ± 2 hours post-CPB, with two subsequent doses at 24 ± 2 hours after the previous dose.

Results

The primary efficacy endpoint is percent change from baseline serum creatinine to mean area under the curve from days 2 through 6. Secondary endpoints include change in estimated glomerular filtration rate from baseline to day 30, the proportion of patients diagnosed with AKI by stage through day 5, and the length of CSA-AKI hospitalization. Safety will include adverse events and laboratory measures.

Conclusion

This phase 2 study of ANG-3777 provides data to develop a phase 3 registrational study in this medically complex condition.

Diverse Receptor Tyrosine Kinase Phosphorylation in Urine-Derived Tubular Epithelial Cells from Autosomal Dominant Polycystic Kidney Disease Patients

BACKGROUNDS

The clinical features of autosomal dominant polycystic kidney disease (ADPKD) differ among patients even if they have the same gene mutation in PKD1 or PKD2. This suggests that there is diversity in the expression of other modifier genes or in the underlying molecular mechanisms of ADPKD, but these are not well understood.

METHODS

We primarily cultured solute carrier family 12 member 3 (SLC12A3)-positive urine-derived distal tubular epithelial cells from 6 ADPKD patients and 4 healthy volunteers and established immortalized cell lines. The diversity in receptor tyrosine kinase (RTK) phosphorylation by phospho-RTK array in immortalized tubular epithelial cells was analyzed.

RESULTS

We noted diversity in the activation of several molecules, including Met, a receptor of hepatocyte growth factor (HGF). Administration of golvatinib, a selective Met inhibitor, or transfection of small interfering RNA for Met suppressed cell proliferation and downstream signaling only in the cell lines in which hyperphosphorylation of Met was observed. In three-dimensional culture of Madin-Darby canine kidney (MDCK) cells as a cyst formation model of ADPKD, HGF activated Met, resulting in an increased total cyst number and total cyst volume. Administration of golvatinib inhibited these phenotypes in MDCK cells.

CONCLUSION

Analysis of urine-derived tubular epithelial cells demonstrated diverse RTK phosphorylation in ADPKD, and Met phosphorylation was noted in some patients. Considering the difference in the effects of golvatinib on immortalized tubular epithelial cells among patients, this analysis may aid in selecting suitable drugs for individual ADPKD patients.

Basic fibroblast growth factor enhances proliferation and hepatocyte growth factor expression of feline mesenchymal stem cells

Introduction

The objective of this study is to evaluate the effect of basic fibroblast growth factor (bFGF) on the proliferation and secretion activity of feline adipose-derived mesenchymal stem cells (MSC).

Methods

Feline MSC isolated from the subcutaneous adipose tissue of cats were cultured with or without bFGF.

Results

The bFGF addition enhanced the proliferation of feline MSC to a significant great extent compared with that without bFGF, although the cell proliferation tended to increase with the bFGF concentration. In addition, adipogenic and osteogenic staining assay demonstrated that the bFGF addition allowed MSC to maintain the differentiation ability even after the proliferation. Moreover, no change in the surface markers of MSC was observed between the cultures with or without bFGF. A quantitative RT-PCR assay revealed that the HGF and TSG-6 expression significantly increased by the bFGF addition. The highest mRNA expression of MMP-2 was observed for cells cultured in 1000 ng/ml bFGF concentration.

Conclusions

The culture with bFGF is a promising way to enhance the proliferation, and HGF secretion ability of MSC as well as maintain their differentiation ability and immunophenotype nature.

•

Feline adipose-derived mesenchymal stem cells (MSC) was cultured with or without the basic fibroblast growth factor (bFGF).

•

The bFGF enhanced the proliferation and increased the mRNA expression of HGF, TSG-6, and MMP-2.

•

The bFGF addition was not influenced to the differentiation ability and cell surface marker of MSC.

A self-assembling peptide hydrogel-based drug co-delivery platform to improve tissue repair after ischemia-reperfusion injury

Ischemia-reperfusion (I/R)-induced organ injury is a serious health problem worldwide, and poor recovery of acute phase injury leads to chronic fibrosis and further organ dysfunction. Thus, a more precise approach to enhance tissue repair is needed. By using a renal I/R model, we aimed to evaluate the role of a hydrogel-based dual-drug delivery platform on promoting tissue repair. An injectable, self-assembling peptide/heparin (SAP/Hep) hydrogel was used to co-deliver TNF-α neutralizing antibody (anti-TNF-α) and hepatocyte growth factor (HGF). The microstructure and controlled release properties of KLD2R/Hep hydrogel were analyzed. The effects of the drug-loaded hydrogel (SAP-drug) on renal injury were evaluated in mice with I/R injury. In vitro, the SAP/Hep hydrogel allowed for a faster release of anti-TNF-α with a sustained release of HGF, and both drugs maintained their bioactivities after release. In vivo, combined anti-TNF-α/HGF showed better renal protective potential than anti-TNF-α or HGF alone. SAP-drug (anti-TNF-α/HGF in SAP hydrogel) treatment reduced the level of serum creatinine (Scr), blood urea nitrogen (BUN), tubular apoptosis, renal inflammatory factors, and macrophage infiltration compared to Free-drug (anti-TNF-α/HGF in solution) or SAP alone. Moreover, the SAP-drug group had better efficacy on promoting tubular cell proliferation and dedifferentiation than SAP or Free-drug alone, and thus reduced chronic renal fibrosis in I/R mice. This study highlighted that SAP could sequentially deliver the two drugs to achieve anti-inflammatory and pro-proliferative effects with one injection and thus is a promising delivery platform for tissue repair. STATEMENT OF SIGNIFICANCE: Ischemia-reperfusion (I/R)-induced organ injury is a serious health issue, and delayed tissue repair leads to chronic fibrosis and organ failure. Systemic administration of anti-inflammatory agents or growth factors have shown some benefits on I/R injury, but their therapeutic efficacy was limited by side effects, poor bioavailability, and absent key signals of tissue repair. To address these issues, a hydrogel-based drug co-delivery platform was used to treat I/R injury. This platform could achieve sequential release kinetics with faster rate of anti-TNF-ɑ and slower rate of HGF, and effectively promoted tissue repair by targeting inflammation and proliferation in mice with renal I/R. This nanoscale delivery platform represents a promising strategy for solid organs (heart, liver and kidney) regeneration after I/R.

Effects of hepatocyte growth factor gene-transfected mesenchymal stem cells on dimethylnitrosamine-induced liver fibrosis in rats

Nowadays, transplantation of human mesenchymal stem cells (MSCs) has emerged as a potential cellular therapy for liver cirrhosis. Hepatocyte growth factor (HGF) plays an important role in the regeneration of the liver. The objective of the study was to investigate the therapeutic effect of HGF-transfected human umbilical cord blood-derived MSCs on dimethylnitrosamine (DMN)-induced liver fibrosis in rats. HGF-transfected MSCs were transplanted into rats with DMN-induced liver fibrosis. H₂O₂-induced cytotoxicity, apoptosis and intracellular reactive oxygen species were reduced in HGF-transfected MSCs in HGF-transfected MSCs. Pro-apoptotic proteins, such as cleaved poly (ADP-ribose) polymerase and cleaved caspase-3, were decreased in HGF-transfected MSCs. Biochemical analysis showed that the levels of aspartate aminotransferase and alanine aminotransferase were decreased after transplantation of HGF-transfected MSCs in rat fibrosis. Trichrome staining showed that HGF-transfected MSCs reduced liver damage. Taken together, our study indicated that HGF-transfected MSCs have therapeutic effects on DMN-induced liver fibrosis in rats.

Hepatocyte Growth Factor Regulates Macrophage Transition to the M2 Phenotype and Promotes Murine Skeletal Muscle Regeneration

Hepatocyte growth factor (HGF) is well known for its role in the migration of embryonic muscle progenitors and the activation of adult muscle stem cells, yet its functions during the adult muscle regeneration process remain to be elucidated. In this study, we showed that HGF/c-met signaling was activated during muscle regeneration, and that among various infiltrated cells, the macrophage is the major cell type affected by HGF. Pharmacological inhibition of the c-met receptor by PHA-665752 increased the expression levels of pro-inflammatory (M1) macrophage markers such as IL-1β and iNOS while lowering those of pro-regenerative (M2) macrophage markers like IL-10 and TGF-β, resulting in compromised muscle repair. In Raw 264.7 cells, HGF decreased the RNA level of LPS-induced TNF-α, IL-1β, and iNOS while enhancing that of IL-10. HGF was also shown to increase the phosphorylation of AMPKα through CaMKKβ, thereby overcoming the effects of the LPS-induced deactivation of AMPKα. Transfection with specific siRNA to AMPKα diminished the effects of HGF on the LPS-induced gene expressions of M1 and M2 markers. Exogenous delivery of HGF through intramuscular injection of the HGF-expressing plasmid vector promoted the transition to M2 macrophage and facilitated muscle regeneration. Taken together, our findings suggested that HGF/c-met might play an important role in the transition of the macrophage during muscle repair, indicating the potential use of HGF as a basis for developing therapeutics for muscle degenerative diseases.

Design and Toxicity Evaluation of Novel Fatty Acid-Amino Acid-Based Biocompatible Surfactants

Surfactants occupy an important place owing to their wide application, but primarily compromised due to its toxicity issues. This raises the need for exploration of newer surfactants with increased biocompatibility. Novel fatty acid- and amino acid-based surfactants were prepared using standard carbodiimide chemistry. Pyrene assay was implemented to confirm the amphiphilic nature of the surfactants and to calculate their CMC (critical micellar concentration). In vitro hemolytic and cell culture study in MCF-7 and HEK cell line were done to check the in vitro biocompatibility of the developed surfactants in comparison to marketed surfactants Triton X-100 and Tween ® 80. In vivo biocompatibility test in female Swiss albino mice was carried out in comparison to marketed surfactants with respect to serum markers, organ histology, and RBC morphology. Surfactant synthesis provided more than 60% yield in all the conjugates. Pyrene assay concluded the amphiphilic nature of the surfactants with lowest CMC of 0.083% w/v in the case of stearic acid and valine conjugate. In vitro hemolytic and cell culture study depicted highest biocompatibility in vitro as compared to marketed surfactants. Similar results were obtained in in vivo biocompatibility with respect to AST (aspartate transaminase), ALT (alanine transaminase), BUN (blood urea nitrogen), and creatinine serum levels and histology of spleen, liver, and kidney in comparison to marketed surfactants Triton X-100 and Tween ® 80. The developed surfactant also depicted least RBC morphology changes in vivo. Stearic acid valine conjugate thus depicted potential for further application in formulation development replacing the commercially available surfactants.

Mesenchymal stromal cells for ocular surface repair

INTRODUCTION

Cornea is a transparent, robust tissue that comprises highly organized cells. Disruption of this specialized tissue can lead to scarring and subsequent blindness, making corneal damage a considerable challenge worldwide. At present, the available medical treatments are unable to address the wide range of corneal diseases. Mesenchymal stem cells (MSCs) have increasingly been investigated for their regenerative effect on ocular surface injury due to their unique ability for growth factor production, anti-inflammatory activity, immunomodulatory capacity and differentiation into multiple cell lineages.

AREAS COVERED

Within this review, we explore the pathogenesis of corneal disorders in response to injury and disease, and the potential for MSCs to modulate this process as a treatment. Through the review of over 25 animal studies, we investigate the common mechanisms of action by which MSCs have their effect and discuss their potential for treating and/or preventing corneal deterioration

EXPERT OPINION

Depending on the environmental cues, MSCs can exert a potent effect on corneal wound healing through reducing opacity and vascularization, whilst promoting re-epithelialization. Whilst their mechanism is multifactorial, it seems clear that the anti-inflammatory/immunomodulatory factors they produce in response to damage are key to their control of cellular milieu and improving healing outcomes.

C-Met as a Key Factor Responsible for Sustaining Undifferentiated Phenotype and Therapy Resistance in Renal Carcinomas

C-Met tyrosine kinase receptor plays an important role under normal and pathological conditions. In tumor cells’ overexpression or incorrect activation of c-Met, this leads to stimulation of proliferation, survival and increase of motile activity. This receptor is also described as a marker of cancer initiating cells. The latest research shows that the c-Met receptor has an influence on the development of resistance to targeted cancer treatment. High c-Met expression and activation in renal cell carcinomas is associated with the progression of the disease and poor survival of patients. C-Met receptor has become a therapeutic target in kidney cancer. However, the therapies used so far using c-Met tyrosine kinase inhibitors demonstrate resistance to treatment. On the other hand, the c-Met pathway may act as an alternative target pathway in tumors that are resistant to other therapies. Combination treatment together with c-Met inhibitor reduces tumor growth, vascularization and pro-metastatic behavior and results in suppressed mesenchymal phenotype and vascular endothelial growth factor (VEGF) secretion. Recently, it has been shown that the acquirement of mesenchymal phenotype or lack of cell differentiation might be related to the presence of the c-Met receptor and is consequently responsible for therapy resistance. This review presents the results from recent studies identifying c-Met as an important factor in renal carcinomas being responsible for tumor growth, progression and metastasis, indicating the role of c-Met in resistance to antitumor therapy and demonstrating the pivotal role of c-Met in supporting mesenchymal cell phenotype.

Hepatocyte Growth Factor-Secreting Mesothelial Cell Sheets Suppress Progressive Fibrosis in a Rat Model of CKD

BACKGROUND

Although hepatocyte growth factor (HGF) has antifibrotic effects and is involved in angiogenesis and vasodilation, systemic administration of HGF to prevent kidney fibrosis is not a feasible strategy for suppressing interstitial fibrosis in patients with CKD.

METHODS

We investigated a novel therapy involving HGF transgenic cell sheets grown in culture from human mesothelial cells and administered to rats with unilateral ureteral obstruction (UUO). We compared progression of fibrosis in rats with UUO that received one of five interventions: HGF-transgenic mesothelial cell sheets transplanted to the kidney surface, HGF-transgenic mesothelial cell sheets transplanted to thigh, mesotherial cell sheets transplanted to kidney, no sheets, or HGF injections.

RESULTS

HGF transgenic cell sheets transplanted to the kidney strongly suppressed the induction of myofibroblasts and collagen in the kidney for 28 days; other interventions did not. Additionally, the HGF-secreting cell sheets ameliorated loss of peritubular capillaries and maintained renal blood flow.

CONCLUSIONS

These findings suggest that cell sheet therapy is a novel and promising strategy for inhibiting progressive fibrosis in CKD.

MET/HGF Co-Targeting in Pancreatic Cancer: A Tool to Provide Insight into the Tumor/Stroma Crosstalk

The ‘onco-receptor’ MET (Hepatocyte Growth Factor Receptor) is involved in the activation of the invasive growth program that is essential during embryonic development and critical for wound healing and organ regeneration during adult life. When aberrantly activated, MET and its stroma-secreted ligand HGF (Hepatocyte Growth Factor) concur to tumor onset, progression, and metastasis in solid tumors, thus representing a relevant target for cancer precision medicine. In the vast majority of tumors, wild-type MET behaves as a ‘stress-response’ gene, and relies on ligand stimulation to sustain cancer cell ‘scattering’, invasion, and protection form apoptosis. Moreover, the MET/HGF axis is involved in the crosstalk between cancer cells and the surrounding microenvironment. Pancreatic cancer (namely, pancreatic ductal adenocarcinoma, PDAC) is an aggressive malignancy characterized by an abundant stromal compartment that is associated with early metastases and resistance to conventional and targeted therapies. Here, we discuss the role of the MET/HGF axis in tumor progression and dissemination considering as a model pancreatic cancer, and provide a proof of concept for the application of dual MET/HGF inhibition as an adjuvant therapy in pancreatic cancer patients.

Lipid and TPGS based novel core-shell type nanocapsular sustained release system of methotrexate for intravenous application

Core shell nanocapsules present an interesting system for attaining high loading of drug. In an attempt, lipid and TPGS based novel core-shell nanocapsule were prepared to achieve high drug loading with sustained release of model hydrophilic drug methotrexate (MTX). Antisolvent nanoprecipitation was utilized for the formulation of nanoparticles. Optimized formulation depicted 223.6 ± 24.1 nm particle size, 0.243 ± 0.034 PDI, zeta potential -2.07 ± 0.51 mV and 15.03 ± 1.92%drug loading. In vitro release showed biphasic release for 12 h with initial burst phase followed by sustained release phase. Haemolytic study on RBCs revealed haemocompatible nature of MTX-TPGS nanoparticles compared to Biotrexate^® (Zydus). In vitro cell culture studies depicted 3 folds and 2.66 folds increase in cellular uptake of MTX at 10 μg/ml and 15 μg/ml respectively for developed nanoparticles with 3.81 folds decrease in IC₅₀ value as compared to Biotrexate^®. Higher apoptosis and increased lysosomal membrane permeability were also depicted by MTX-TPGS nanoparticles. 2.45 folds increase in AUC and 3.68 folds increase in T_1/2 was achieved in pharmacokinetic study. Significant reduction in tumor burden and serum biochemical parameters depicted efficacy and safety respectively of the formulation as compared to Biotrexate^®. RBCs morphology was retained after MTX-TPGS exposure proving its haemocompatibility in vivo.

Cellular signaling and gene expression profiles evoked by a bivalent macrocyclic peptide that serves as an artificial MET receptor agonist

Non-native ligands for growth factor receptors that are generated by chemical synthesis are applicable to therapeutics. However, non-native ligands often regulate cellular signaling and biological responses in a different manner than native ligands. Generation of surrogate ligands comparable to native ligands is a challenging need. Here we investigated changes in signal transduction and gene expression evoked by a bivalent macrocyclic peptide (aMD5-PEG11) capable of high-affinity binding to the MET/hepatocyte growth factor (HGF) receptor. Binding of aMD5-PEG11 to the MET extracellular region was abolished by deletion of the IPT3−IPT4 domain, indicating the involvement of IPT3−IPT4 in the binding of aMD5-PEG11 to the MET receptor. aMD5-PEG11 induced dimerization and activation of the MET receptor and promoted cell migration that was comparable to induction of these activities by HGF. Signal activation profiles indicated that aMD5-PEG11 induced phosphorylation of intracellular signaling molecules, with a similar intensity and time dependency as HGF. In 3-D culture, aMD5-PEG11 as well as HGF induced epithelial tubulogenesis and up-regulated the same sets of functionally classified genes involved in multicellular organism development. Thus, a non-native surrogate ligand that consisted of a bivalent macrocyclic peptide can serve as an artificial MET receptor agonist that functionally substitutes for the native ligand, HGF.

Bioactive Compounds for the Treatment of Renal Disease

Kidney diseases including acute kidney injury and chronic kidney disease are among the largest health issues worldwide. Dialysis and kidney transplantation can replace a significant portion of renal function, however these treatments still have limitations. To overcome these shortcomings, a variety of innovative efforts have been introduced, including cell-based therapies. During the past decades, advances have been made in the stem cell and developmental biology, and tissue engineering. As part of such efforts, studies on renal cell therapy and artificial kidney developments have been conducted, and multiple therapeutic interventions have shown promise in the pre-clinical and clinical settings. More recently, therapeutic cell-secreting secretomes have emerged as a potential alternative to cell-based approaches. This approach involves the use of renotropic factors, such as growth factors and cytokines, that are produced by cells and these factors have shown effectiveness in facilitating kidney function recovery. This review focuses on the renotropic functions of bioactive compounds that provide protective and regenerative effects for kidney tissue repair, based on the available data in the literature.

Hepatocyte Growth Factor Regulates the miR-206-HDAC4 Cascade to Control Neurogenic Muscle Atrophy following Surgical Denervation in Mice

Hepatocyte growth factor (HGF) has been well characterized for its roles in the migration of muscle progenitors during embryogenesis and the differentiation of muscle stem cells, but its function in adult neurogenic muscle atrophic conditions is poorly understood. Here we investigated whether HGF/c-met signaling has any effects on muscle-atrophic conditions. It was found that HGF expression was upregulated in skeletal muscle tissue following surgical denervation and in hSOD1-G93A transgenic mice showing severe muscle loss. Pharmacological inhibition of the c-met receptor decreased the expression level of pri-miR-206, enhanced that of HDAC4 and atrogenes, and resulted in increased muscle atrophy. In C2C12 cells, HGF inhibited phosphorylation of Smad3 and relieved TGF-β-mediated suppression of miR-206 expression via JNK. When extra HGF was exogenously provided through intramuscular injection of plasmid DNA expressing HGF, the extent of muscle atrophy was reduced, and the levels of all affected biochemical markers were changed accordingly, including those of primary and mature miR-206, HDAC4, and various atrogenes. Taken together, our finding suggested that HGF might play an important role in regard to neurogenic muscle atrophy and that HGF might be used as a platform to develop therapeutic agents for neuromuscular disorders.

Therapeutic effects of hepatocyte growth factor-overexpressing dental pulp stem cells on liver cirrhosis in a rat model

Cirrhosis is the terminal stage of hepatic diseases and is prone to develop into hepatocyte carcinoma. Increasing evidence suggests that the transplantation of dental pulp stem cells (DPSCs) may promote recovery from cirrhosis, but the key regulatory mechanisms involved remain to be determined. In this study, we overexpressed human hepatocyte growth factor (hHGF) in primary rat DPSCs and evaluated the effects of HGF overexpression on the biological behaviors and therapeutic efficacy of grafted DPSCs in cirrhosis. Liver cirrhosis was induced via the intraperitoneal injection of CCl₄ twice weekly for 12 weeks and was verified through histopathological and serological assays. HGF was overexpressed in DPSCs via transduction with a hHGF-lentiviral vector and confirmed based on the elevated expression and secretion of HGF. The HGF-overexpressing DPSCs were transplanted into rats intravenously. The HGF-overexpressing DPSCs showed increased survival and hepatogenic differentiation in host liver tissue at 6 weeks after grafting. They also exhibited a significantly greater repair potential in relation to cirrhosis pathology and impaired liver function than did DPSCs expressing HGF at physiological levels. Our study may provide an experimental basis for the development of novel methods for the treatment of liver cirrhosis in clinical practice.

Placenta-derived PLX-PAD mesenchymal-like stromal cells are efficacious in rescuing blood flow in hind limb ischemia mouse model by a dose- and site-dependent mechanism of action

BACKGROUND

In peripheral artery disease (PAD), blockage of the blood supply to the limbs, most frequently the legs, leads to impaired blood flow and tissue ischemia. Pluristem's PLX-PAD cells are placenta-derived mesenchymal stromal-like cells currently in clinical trials for the treatment of peripheral artery diseases.

METHODS

In this work, the hind limb ischemia (HLI) mouse model was utilized to study the efficacy and mechanism of action of PLX-PAD cells. ELISA assays were performed to characterize and quantitate PLX-PAD secretions in vitro.

RESULTS

PLX-PAD cells administered intramuscularly rescued blood flow to the lower limb after HLI induction in a dose-dependent manner. While rescue of blood flow was site-dependent, numerous administration regimes enabled rescue of blood flow, indicating a systemic effect mediated by PLX-PAD secretions. Live PLX-PAD cells were more efficacious than cell lysate in rescuing blood flow, indicating the importance of prolonged cytokine secretion for maximal blood flow recovery. In vitro studies showed a multifactorial secretion profile including numerous pro-angiogenic proteins; these are likely involved in the PLX-PAD mechanism of action.

DISCUSSION

Live PLX-PAD cells were efficacious in rescuing blood flow after the induction of HLI in the mouse model in a dose- and site-dependent manner. The fact that various administration routes of PLX-PAD rescued blood flow indicates that the mechanism of action likely involves one of systemic secretions which promote angiogenesis. Taken together, the data support the further clinical testing of PLX-PAD cells for PAD indications.

High glucose induces HGF-independent activation of Met receptor in human renal tubular epithelium

CONTEXT

The role of hepatocyte growth factor (HGF) in diabetic kidney damage remains controversial.

OBJECTIVE

To test the hypothesis that high glucose levels activate pathways related to HGF and its receptor Met and that this could participate in glucose-induced renal cell damage.

MATERIALS AND METHODS

HK2 cells, a human proximal tubule epithelial cell line, were stimulated with high glucose for 48 hours. Levels of pMet/Met, pEGFR/EGFR, pSTAT3/STAT3, pAkt/Akt and pERK1/2/ERK1/2 were studied by immunoblotting. Absence of HGF was verified by qRT-PCR and ELISA.

RESULTS

High glucose level activated Met and its downstream pathways STAT3, Akt and ERK independently of HGF. High glucose induced an integrin ligand fibronectin. HGF-independent Met phosphorylation was prevented by inhibition of integrin α5β1, Met inhibitor crizotinib, Src inhibitors PP2 and SU5565, but not by EGFR inhibitor AG1478. High glucose increased the expression of TGFβ-1, CTGF and the tubular damage marker KIM-1 and increased apoptosis of HK2 cells, effects inhibited by crizotinib.

CONCLUSION

High glucose activated Met receptor in HK2 cells independently of HGF, via induction of integrin α5β1 and downstream signaling. This mode of Met activation was associated with tubular cell damage and apoptosis and it may represent a novel pathogenic mechanism and a treatment target in diabetic nephropathy.

The Regenerative Potential of Stem Cells in Acute Renal Failure

Adult stem cells have been characterized in several tissues as a subpopulation of cells able to maintain, generate, and replace terminally differentiated cells in response to physiological cell turnover or tissue injury. Little is known regarding the presence of stem cells in the adult kidney but it is documented that under certain conditions, such as the recovery from acute injury, the kidney can regenerate itself by increasing the proliferation of some resident cells. The origin of these cells is largely undefined; they are often considered to derive from resident renal stem or progenitor cells. Whether these immature cells are a subpopulation preserved from the early stage of nephrogenesis is still a matter of investigation and represents an attractive possibility. Moreover, the contribution of bone marrow-derived stem cells to renal cell turnover and regeneration has been suggested. In mice and humans, there is evidence that extrarenal cells of bone marrow origin take part in tubular epithelium regeneration. Injury to a target organ can be sensed by bone marrow stem cells that migrate to the site of damage, undergo differentiation, and promote structural and functional repair. Recent studies have demonstrated that hematopoietic stem cells were mobilized following ischemia/reperfusion and engrafted the kidney to differentiate into tubular epithelium in the areas of damage. The evidence that mesenchymal stem cells, by virtue of their renoprotective property, restore renal tubular structure and also ameliorate renal function during experimental acute renal failure provides opportunities for therapeutic intervention.