Simvastatin inhibits transforming growth factor-β1-induced expression of type I collagen, CTGF, and α-SMA in keloid fibroblasts

POSTN Regulates Fibroblast Proliferation and Migration in Laryngotracheal Stenosis Through the TGF-β/RHOA Pathway

OBJECTIVES

To investigate the role of periostin (POSTN) and the transforming growth factor β (TGF-β) pathway in the formation of laryngotracheal stenosis (LTS) scar fibrosis and to explore the specific signaling mechanism of POSTN-regulated TGF-β pathway in tracheal fibroblasts.

METHODS

Bioinformatics analysis was performed on scar data sets from the GEO database to preliminarily analyze the involvement of POSTN and TGF-β pathways in fibrosis diseases. Expression of POSTN and TGF-β pathway-related molecules was analyzed in LTS scar tissue at the mRNA and protein levels. The effect of POSTN on the biological behavior of tracheal fibroblasts was studied using plasmid DNA overexpression and siRNA silencing techniques to regulate POSTN expression and observe the activation of TGF-β1 and the regulation of cell proliferation and migration via the TGF-β/RHOA pathway.

RESULTS

The bioinformatics analysis revealed that POSTN and the TGF-β pathway are significantly involved in fibrosis diseases. High expression of POSTN and TGF-β/RHOA pathway-related molecules (TGFβ1, RHOA, CTGF, and COL1) was observed in LTS tissue at both mRNA and protein levels. In tracheal fibroblasts, overexpression or silencing of POSTN led to the activation of TGF-β1 and regulation of cell proliferation and migration through the TGF-β/RHOA pathway.

CONCLUSION

POSTN is a key molecule in scar formation in LTS, and it regulates the TGF-β/RHOA pathway to mediate the formation of cicatricial LTS by acting on TGF-β1. This study provides insights into the molecular mechanisms underlying LTS and suggests potential therapeutic targets for the treatment of this condition.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:4078-4087, 2024.

Pharmacotherapy for Keloids and Hypertrophic Scars

Keloids (KD) and hypertrophic scars (HTS), which are quite raised and pigmented and have increased vascularization and cellularity, are formed due to the impaired healing process of cutaneous injuries in some individuals having family history and genetic factors. These scars decrease the quality of life (QOL) of patients greatly, due to the pain, itching, contracture, cosmetic problems, and so on, depending on the location of the scars. Treatment/prevention that will satisfy patients' QOL is still under development. In this article, we review pharmacotherapy for treating KD and HTS, including the prevention of postsurgical recurrence (especially KD). Pharmacotherapy involves monotherapy using a single drug and combination pharmacotherapy using multiple drugs, where drugs are administered orally, topically and/or through intralesional injection. In addition, pharmacotherapy for KD/HTS is sometimes combined with surgical excision and/or with physical therapy such as cryotherapy, laser therapy, radiotherapy including brachytherapy, and silicone gel/sheeting. The results regarding the clinical effectiveness of each mono-pharmacotherapy for KD/HTS are not always consistent but rather scattered among researchers. Multimodal combination pharmacotherapy that targets multiple sites simultaneously is more effective than mono-pharmacotherapy. The literature was searched using PubMed, Google Scholar, and Online search engines.

Diagnosis and Treatment of Keloid: Method Summary and Effect Evaluation

Keloid is a prevalent skin disorder characterized by the abnormal growth of keloid tissue, which usually occurs following wound healing or surgical incisions. It typically progresses through several stages: the inflammatory stage, the proliferative stage, collagen remodeling, and ultimately the formation of keloid. This review aims to summarize the diagnostic and therapeutic methods for keloid, and evaluate their effectiveness. The diagnosis of keloid is usually based on medical history and clinical manifestations such as pain, itching, erythema, and induration. Other commonly used diagnostic methods include tissue biopsy and ultrasound examination. Various treatment options for keloid exist, including physical therapy, medication, surgical treatment, and radiation therapy. Physical therapy includes pressure therapy, laser therapy, such as silicone sheets, elastic bandages, and laser irradiation. Medication treatment mainly involves the application of topical medications or intralesional injections, such as topical corticosteroids, 5-fluorouracil, and others. Radiation therapy can be administered using applicators and superficial radiation therapy, among other methods. The treatment outcomes of keloid vary from person to person and recurrence is common. Therefore, a comprehensive treatment approach may be the most effective strategy. Individualized treatment plans should consider factors such as the patient's age, gender, medical history, and the severity of the condition. In conclusion, the diagnosis and treatment of keloid require consideration of multiple factors and the implementation of individualized treatment plans. Future research should focus on identifying the molecular mechanisms underlying the occurrence and progression of keloid in order to develop more effective treatment methods.

Anti-fibrotic effects of statin drugs: a review of evidence and mechanisms

Fibrosis is a pathological repair process common among organs, that responds to damage by replacement of tissue with non-functional connective tissue. Despite the widespread prevalence of tissue fibrosis, manifesting in numerous disease states across myriad organs, therapeutic modalities to prevent or alleviate fibrosis are severely lacking in quantity and efficacy. Alongside development of new drugs, repurposing of existing drugs may be a complementary strategy to elect anti-fibrotic compounds for pharmacologic treatment of tissue fibrosis. Drug repurposing can provide key advantages to de novo drug discovery, harnessing the benefits of previously elucidated mechanisms of action and already existing pharmacokinetic profiles. One class of drugs a wealth of clinical data and extensively studied safety profiles is the statins, a class of antilipidemic drugs widely prescribed for hypercholesterolemia. In addition to these widely utilized lipid-lowering effects, increasing data from cellular, pre-clinical mammalian, and clinical human studies have also demonstrated that statins are able to alleviate tissue fibrosis originating from a variety of pathological insults via lesser-studied, pleiotropic effects of these drugs. Here we review literature demonstrating evidence for direct effects of statins antagonistic to fibrosis, as well as much of the available mechanistic data underlying these effects. A more complete understanding of the anti-fibrotic effects of statins may enable a clearer picture of their anti-fibrotic potential for various clinical indications. Additionally, more lucid comprehension of the mechanisms by which statins exert anti-fibrotic effects may aid in development of novel therapeutic agents that target similar pathways but with greater specificity or efficacy.

Ursolic acid inhibits human dermal fibroblasts hyperproliferation, migration, and collagen deposition induced by TGF-β via regulating the Smad2/3 pathway

Hypertrophic scar (HS) is a skin condition characterized by excessive fibrosis with disordered collagens from skin fibroblasts, which causes abnormal esthetic and even functional symptoms, thereby affecting millions of people. Ursolic acid (UA) is widely used in skincare and exerts anti-fibrotic effects. The present study aimed to delve into the impact of UA on HS and the mechanism. Fibroblasts (FBs) were incubated with TGF-β to investigate physiological characteristics compared with FBs isolated from normal skin (NSFBs) and hyperplastic scars (HSFBs). TGF-β-incubated FBs were subjected to treatment with UA (0-20 μM). The expressions of Vimentin, α-SMA, Collagen I, and Collagen III were examined using immunofluorescence, RT-qPCR, and western blot. Cell viability, proliferation, apoptosis, migration, and contractility were examined by CCK-8, EdU, Annexin V-FITC/PI, Transwell, and collagen gel contraction assays, respectively. The activation of Smad2/3 signaling was also determined by western blot. The binding sites for UA of TGF-βR1 (ALK5) were predicted by the Autodock tool. Compared with NSFBs, the cell proliferation, migration, and contractility of both HSFBs and TGF-β-incubated FBs were all significantly up-regulated. UA markedly impaired the TGF-β-induced increase in cell proliferation, migration, and contractility, α-SMA, collagen I, and Collagen III expression of FBs. UA significantly inhibited the phosphorylation levels of Smad2/3 in TGF-β-incubated FBs with no influence on TGF-βR1 and TGF-βR2 expressions, which might be because of the binding of UA to the catalytic domain of ALK5 protein. UA attenuated TGF-β1-induced hyperproliferation, migration, and collagen deposition in FBs via regulating the Smad2/3 pathway.

Biomechanical Regulatory Factors and Therapeutic Targets in Keloid Fibrosis

Keloids are fibroproliferative skin disorder caused by abnormal healing of injured or irritated skin and are characterized by excessive extracellular matrix (ECM) synthesis and deposition, which results in excessive collagen disorders and calcinosis, increasing the remodeling and stiffness of keloid matrix. The pathogenesis of keloid is very complex, and may include changes in cell function, genetics, inflammation, and other factors. In this review, we aim to discuss the role of biomechanical factors in keloid formation. Mechanical stimulation can lead to excessive proliferation of wound fibroblasts, deposition of ECM, secretion of more pro-fibrosis factors, and continuous increase of keloid matrix stiffness. Matrix mechanics resulting from increased matrix stiffness further activates the fibrotic phenotype of keloid fibroblasts, thus forming a loop that continuously invades the surrounding normal tissue. In this process, mechanical force is one of the initial factors of keloid formation, and matrix mechanics leads to further keloid development. Next, we summarized the mechanotransduction pathways involved in the formation of keloids, such as TGF-β/Smad signaling pathway, integrin signaling pathway, YAP/TAZ signaling pathway, and calcium ion pathway. Finally, some potential biomechanics-based therapeutic concepts and strategies are described in detail. Taken together, these findings underscore the importance of biomechanical factors in the formation and progression of keloids and highlight their regulatory value. These findings may help facilitate the development of pharmacological interventions that can ultimately prevent and reduce keloid formation and progression.

Protective effect of rosuvastatin against the formation of benign esophageal stricture

BACKGROUND

Benign esophageal strictures result from caustic or radiation injury or surgical procedures. Statins have anti-inflammatory and anti-fibrotic activities. We examined the role of rosuvastatin in preventing benign esophageal fibrosis and stricture formation in a rabbit model.

METHODS

Twenty-six rabbits were assigned to control and rosuvastatin groups. The rabbits in the rosuvastatin group were administered rosuvastatin 5 mg/day, 2 weeks prior to the esophageal stricture phase. Esophageal strictures were established by applying 4% sodium hydroxide solution to the middle esophagus. Esophagography was performed to evaluate the degree of esophageal stenosis, and histopathologic assessment of esophageal tissue damage was performed with hematoxylin-eosin and Masson staining. The expressions of transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), and α-smooth muscle actin (α-SMA) were examined by immunohistochemistry.

RESULTS

The incidence of strictures was significantly lower in the rosuvastatin group. Esophagography demonstrated mild stenosis in the narrowest inner esophageal diameter in the rosuvastatin group than in the control group, and Masson staining demonstrated significantly less collagen deposition in the rosuvastatin group. In addition, immunohistochemistry results showed that the expressions of TGF-β1, CTGF, and α-SMA significantly reduced in the rosuvastatin group.

CONCLUSIONS

The present study demonstrated that rosuvastatin prevents benign esophageal stricture formation. This effect may be exerted through the anti-fibrotic activity of rosuvastatin, which may be exerted by the inhibition of CTGF and α-SMA production induced by TGF-β1.

Development of Anti-fibrotic Therapy in Stricturing Crohn's Disease: Lessons from Randomized Trials in Other Fibrotic Diseases

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective anti-fibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver and skin. In this review, we summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

Comparing the wound healing effect of a controlled release wound dressing containing curcumin/ciprofloxacin and simvastatin/ciprofloxacin in a rat model: A preclinical study

Inflammation and infection are two main factors predisposing a wound to become a chronic one. Degradable wound dressings involving the controlled release of suitable drugs at the ulcer site are one of the solutions to make wounds healing progress smoothly and rapidly. In this research, biodegradable dressings made of polyglycerol sebacate/polycaprolactone (PGS/PCL) containing curcumin/ciprofloxacin (CUR/CIP) and simvastatin/ciprofloxacin (SIM/CIP) were prepared by using the coaxial electrospinning method. Transmission electron microscopy for uniform core/shell structure, swelling ratio, and drug release pattern of the wound dressings were evaluated. At the in vivo study, histometric, histopathologic, and collagen expression study was performed. The PGS/PCL samples containing SIM/CIP showed a burst release pattern of CIP with a delay in the release of SIM; meanwhile, in the samples containing CUR/CIP, both drugs showed a burst release behavior. No cytotoxicity response was observed in the study groups. The in vivo study showed that wound closure was almost completed only in the SIM/CIP group after 14 days. After 14 days, in the wound treated with SIM/CIP dressing, the amount of collagen deposition and angiogenesis was higher than that of the others. These results clearly showed the effect of SIM/CIP on the improvement of the wound healing efficiency in the long term (14 days) and the effect of CUR/CIP on wound contraction in the short term (4 day). It seems, therefore, that the use of SIM and CUR simultaneously in a wound dressing could cause a synergistic effect in the wound repair.

The Combination of Electroacupuncture and Massage Therapy Alleviates Myofibroblast Transdifferentiation and Extracellular Matrix Production in Blunt Trauma-Induced Skeletal Muscle Fibrosis

Complementary therapies, such as acupuncture and massage, had been previously reported to have therapeutic effects on skeletal muscle contusions. However, the recovery mechanisms on skeletal muscles after blunt trauma via the combination of electroacupuncture (EA) and massage therapy remain unclear. In the present study, a rat model of the skeletal muscle fibrosis following blunt trauma to rat skeletal muscle was established, and the potential molecular mechanisms of EA + massage therapy on the skeletal muscle fibrosis were investigated. The results suggested that EA + massage therapy could significantly decrease inflammatory cells infiltration and collagenous fiber content and ameliorate the disarrangement of sarcomeres within myofibrils compared to the model group. Further analysis revealed that EA + massage therapy could reduce the degree of fibrosis and increase the degree of myofibroblast apoptosis by downregulating the mRNA and protein expression of transforming growth factor- (TGF-) β1 and connective tissue growth factor (CTGF). Furthermore, the fibrosis of injured skeletal muscle was inhibited after treatment through the normalization of balance between matrix metalloproteinase- (MMP-) 1 and tissue inhibitor of matrix metalloproteinase (TIMP). These findings suggested that the combination of electroacupuncture and massage therapy could alleviate the fibrotic process by regulating TGF β1-CTGF-induced myofibroblast transdifferentiation and MMP-1/TIMP-1 balance for extracellular matrix production.

Antifibrotic effects of Hypocrellin A combined with LED red light irradiation on keloid fibroblasts by counteracting the TGF-β/Smad/autophagy/apoptosis signalling pathway

Keloids are characterized by abnormal proliferation of fibroblasts and continuous deposition of extracellular matrix (ECM) components. In the field of dermopathy, photodynamic therapy (PDT) with visible light has been increasingly investigated. The natural photosensitizer Hypocrellin A (HA) was shown to have excellent light induced anticancer, antimicrobial and antiviral activities. In this experiment, we investigated the impacts of HA united light-emitting diode (LED) red light irradiation on human keloid fibroblast cells (KFs). Our results showed that HA combined with red light irradiation treatment (HA-R-PDT) decreased KF viability, reduced KF collagen production and ECM accumulation, inhibited cell proliferation, suppressed cell invasion and induced cell apoptosis. Moreover, our observations demonstrated that the TGF-β/Smad signalling pathway and autophagy were restrained by HA-R-PDT. TGF-β1 could promote autophagy in KFs through both the Smad and ERK pathways, while inhibition of autophagy altered the TGF-β1 levels through negative feedback. Therefore, HA-R-PDT suppressed cell hyperproliferation, collagen synthesis and ECM accumulation of KFs by regulating the TGF-β1-ERK-autophagy-apoptosis signalling pathway. HA-R-PDT deserves systematic investigation as a potential therapeutic strategy for keloids, and autophagy might be a promising candidate in the treatment of KFs.

Statin treatment and hypertrophic scarring after cardiac surgery

Wound healing process after surgical procedure plays a crucial role to prevent blood loss and infections. Hypertrophic scars might occur after surgery and are generally associated with an inflammatory burden. Cardiac surgery is intrinsically related to a strong systemic inflammatory state that might favor hypertrophic scarring. Besides lipid-lowering effects, statins are known for their pleiotropic and anti-inflammatory activity. The aim of this study was to investigate the impact of statins in the healing process after median sternotomy in patients undergoing cardiac surgery. All patients undergoing major cardiac surgery with median sternotomy and cardiopulmonary bypass, and subsequently evaluated in the outpatient clinic after discharge, were included in this study. A total of 930 Caucasian patients were retrospectively reviewed. At outpatient visit, 276 patients (29.7%) showed the formation of hypertrophic scars. Patients with hypertrophic scars tended to be younger (P = .001) and nonstatin users (P = .001). Logistic regression analysis confirmed the protective role of statins (odds ratio 0.39, 95% confidence interval 0.29-0.53, P = .001), after adjustment for age. A dose-dependent effect was confirmed, showing a more intensive protective effect for higher doses of statins. Statin use might be correlated with reduced hypertrophic scars after cardiac surgery through median sternotomy. A dose-dependent effect has been shown, and statin effect seems to be independent of age in a selected population undergoing surgery with an elevated inflammatory burden. Although further studies are warranted to elucidate the biologic mechanisms, the concept of using statins as anti-scarring agents is novel and should be investigated with tailored studies.

Liposome-encapsulated statins reduce hypertrophic scarring through topical application

Hypertrophic scar is an important clinical problem with limited therapeutic options. Aside from their roles as 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, statins have also been demonstrated to decrease scarring by reducing connective tissue growth factor (CTGF) expression. However, poor penetrative ability limits their utility as topical treatments for hypertrophic scar. Here, we aim to develop novel statin formulations using liposomes to enhance dermal penetrative ability and to evaluate their efficacy against formation of hypertrophic scar utilizing our validated rabbit ear hypertrophic scar model. Liposomal simvastatin or pravastatin were compounded using a novel, flexible liposomal formulation and applied topically to rabbit ear hypertrophic scars daily from postoperation day (POD) 14 until POD 25. Scar color, including erythema and melanin, was measured using reflectance spectrophotometry on POD 28, and scar tissue was harvested for evaluation of scar elevation index as well as gene and protein expression. Human foreskin fibroblasts were also treated with statin formulations and CCN2 expression was determined by quantitative PCR. Both simvastatin and pravastatin were efficiently encapsulated in liposomes, forming nanometer-scale particles possessing highly negative charges. Topical treatment with liposomal simvastatin and pravastatin at 6.5% concentration significantly reduced scar elevation index and decreased type I/III collagen content and myofibroblast persistence in the wound. The erythema/vascularity of scars was reduced by liposomal statin treatment, with concomitant decrease of CD31 expression as measured histologically. Expression levels of transcripts encoding CTGF, collagen I, and collagen III collagen in scar tissue were also decreased by liposomal pravastatin treatment, as were myofibroblast persistence and the type I/III collagen ratio as assessed by immunofluorescence and picrosirus red staining, respectively. Treatment of human foreskin fibroblasts with simvastatin or with liposome-encapsulated pravastatin resulted in decreased expression of transcript encoding CTGF. Overall, our novel statin formulations encapsulated in liposomes were successfully delivered through topical application, significantly reducing hypertrophic scarring in a rabbit ear model.

Modulating cationicity of chitosan hydrogel to prevent hypertrophic scar formation during wound healing

It is of great clinical significance to design wound dressing materials with combined excellent wound healing properties and superior capability to suppress hypertrophic scar formation. This study aimed to examine if and how the cationicity of chitosan would affect the hypertrophic scar-related outcomes, through preparing carboxymethyl chitosan hydrogels with different genipin concentrations (2.5%, 5%, 10% and 15%, respectively). An optimum window of chitosan cationicity (5% in our case) demonstrated potential to mitigate hypertrophic scar in wound healing by suppressing the expression of a-smooth muscle actin (a-SMA) and promoting secretion of type I matrix metalloproteinases (MMP-1). In vivo, the CMCS-5% hydrogel again showed smaller, thinner and smoother wound appearance. Moreover, the CMCS-5% sample with additional incorporation of 2% (V/V) Aloe vera gel exhibited further improved performance in scar inhibition. Overall, such findings might have important implications in chitosan-based wound dressing design for high-quality wound repair and effective scar inhibition.

Potential effect of non-thermal plasma for the inhibition of scar formation: a preliminary report

Non-thermal plasma (NTP) is a promising biomedical tool for application to wound healing. However, there is limited scientific evidence that confirms its efficacy to inhibit scar formation. This study aims to investigate the role of non-thermal plasma in scar formation. Two full-thickness dorsal cutaneous wounds of rats were treated with either a non-thermal helium plasma jet or helium. It was determined that the non-thermal plasma jet accelerated the wound healing process from 5 days after surgery (day 5: 41.27% ± 2.351 vs 54.7% ± 5.314, p < 0.05; day 7: 56.05% ± 1.881 vs 75.28% ± 3.914, p < 0.01; day 14: 89.85% ± 2.991 vs 98.07% ± 0.839, p < 0.05). The width of the scars for the NTP group was narrower than those of control group (4.607 ± 0.416 mm vs 3.260 ± 0.333 mm, p < 0.05). In addition, a lower level of TGF-β1, p-Smad2 and p-Smad3 were detected in the NTP treated wounds (p < 0.05, p < 0.01 and p < 0.01). As expected, α-SMA was also significantly decreased in the NTP treatment group (p < 0.01). Moreover, the expression of type I collagen and the proportion of type I to III collagen were lower in the NTP group (p < 0.05). The results of the study suggest that NTP may play a potential role in scar formation by inhibiting the TGF β1 signal pathway and reducing the levels of α-SMA and type I collagen, and may have clinical utility in the future.

Simvastatin and ROCK Inhibitor Y-27632 Inhibit Myofibroblast Differentiation of Graves' Ophthalmopathy-Derived Orbital Fibroblasts via RhoA-Mediated ERK and p38 Signaling Pathways

Transforming growth factor-β (TGF-β)-induced differentiation of orbital fibroblasts into myofibroblasts is an important pathogenesis of Graves' ophthalmopathy (GO) and leads to orbital tissue fibrosis. In the present study, we explored the antifibrotic effects of simvastatin and ROCK inhibitor Y-27632 in primary cultured GO orbital fibroblasts and tried to explain the molecular mechanisms behind these effects. Both simvastatin and Y-27632 inhibited TGF-β-induced α-smooth muscle actin (α-SMA) expression, which serves as a marker of fibrosis. The inhibitory effect of simvastatin on TGF-β-induced RhoA, ROCK1, and α-SMA expression could be reversed by geranylgeranyl pyrophosphate, an intermediate in the biosynthesis of cholesterol. This suggested that the mechanism of simvastatin-mediated antifibrotic effects may involve RhoA/ROCK signaling. Furthermore, simvastatin and Y-27632 suppressed TGF-β-induced phosphorylation of ERK and p38. The TGF-β-mediated α-SMA expression was suppressed by pharmacological inhibitors of p38 and ERK. These results suggested that simvastatin inhibits TGF-β-induced myofibroblast differentiation via suppression of the RhoA/ROCK/ERK and p38 MAPK signaling pathways. Thus, our study provides evidence that simvastatin and ROCK inhibitors may be potential therapeutic drugs for the prevention and treatment of orbital fibrosis in GO.

In Vitro and Ex Vivo Models for Functional Testing of Therapeutic Anti-scarring Drug Targets in Keloids

Significance: Keloids are benign fibro-proliferative raised dermal lesions that spread beyond the original borders of the wound, continue to grow, rarely regress, and are the most common in pigmented individuals after an abnormal wound healing response. The current treatment failure and respective challenges involved highlighting the underlying issue that the etiopathogenesis of keloids is still not well understood. Disease models are required to better understand the disease pathogenesis. It is not possible to establish keloids in animals because of the uniqueness of this disease to human skin. To address this challenge, along these lines, non-animal reproducible models are vital in investigating molecular mechanisms of keloid pathogenesis and therapeutics development. Recent Advances: Various non-animal models have been developed to better understand the molecular mechanisms involved in keloid scarring and aid in identifying and evaluating the therapeutic potential of novel drug candidates. In this scenario, the current review aims at describing in vitro monocultures, co-cultures, organotypic cultures, and ex vivo whole skin keloid tissue organ culture models. Critical Issues and Future Directions: Current treatment options for keloids are far from securing a cure or preventing disease recurrence. Identifying universally accepted effective therapy for keloids has been hampered by the absence of appropriate disease model systems. Animal models do not accurately mimic the disease, thus non-animal model systems are pivotal in keloid research. The use of these models is essential not only for a better understanding of disease biology but also for identifying and evaluating novel drug targets.

Mycobacterium tuberculosis induces connective tissue growth factor expression through the TLR2-JNK-AP-1 pathway in human lung fibroblasts

Mycobacterium tuberculosis (M.tb) infection in lung causes pulmonary fibrosis, which leads to the irreversible reduction of pulmonary function. Fibrotic protein connective tissue growth factor (CTGF) expression has been confirmed to play a crucial role in lung fibrosis. However, the underlying signal pathway and effect of M.tb on CTGF expression in human lung fibroblasts are unclear. Our results revaled that M.tb caused time- and concentration-dependent increases in CTGF expression in human lung fibroblasts. A mechanistic investigation revealed that M.tb induced CTGF expression through TLR2 but not TLR4. The promoter activity assay indicated that M.tb-induced CTGF activity was mainly controlled by the promoter region at -747 to -184 bp, which contained signal transducer and activator of transcription 3 and activator protein 1 (AP-1) binding sites. Moreover, curcumin (AP-1 inhibitor) restrained M.tb-induced CTGF expression. M.tb also induced increases in AP-1 luciferase activity and DNA binding activity of c-Jun and c-Fos on the CTGF promoter. Furthermore, the knockdown of c-Jun by small interfering RNA attenuated M.tb-induced CTGF expression and AP-1 luciferase activity. A JNK inhibitor (SP600125) and a JNK dominant-negative mutant suppressed M.tb-induced CTGF expression. We also discovered that M.tb could induce the phosphorylation of JNK and c-Jun. Furthermore, SP600125 inhibited M.tb-induced c-Jun phosphorylation and AP-1- luciferase activity. M.tb-induced fibronectin expression was inhibited by anti-CTGF antibody. These results demonstrate that M.tb is activated through TLR2 to induce JNK activation, further increasing the DNA binding activity of c-Jun and c-Fos and finally inducing CTGF expression and extracellular matrix production.-Lee, H.-S., Hua, H.-S., Wang, C.-H., Yu, M.-C., Chen, B.-C., Lin, C.-H. Mycobacterium tuberculosis induces connective tissue growth factor expression through the TLR2-JNK-AP-1 pathway in human lung fibroblasts.

Comparison of the effects of pentoxifylline, simvastatin, tamoxifen, and losartan on cavernous bodies after penile fracture in rats: a stereological study

Penile fracture (PF) is described as a rupture and fibrosis of the cavernous bodies. This study aimed to collect quantitative data on the impacts of pentoxifylline, simvastatin, tamoxifen, and losartan on cavernous body structure after PF. The rats were divided into six groups. The control group received anesthesia and incision without actual PF. The other groups (second to sixth) underwent PF induction in addition to administration of distilled water, pentoxifylline (200 mg/kg/day), simvastatin (40 mg/kg/day), tamoxifen (10 mg/kg/day), and losartan (20 mg/kg/day) for 8 weeks. The volumes of cavernous bodies, collagen bundles, and vessels and number of fibroblasts were increased significantly in the PF group in comparison to the control rats (p < 0.01), indicating a fibrotic process. Moreover, the mean volume of the cavernous bodies decreased in the groups with PF that received pentoxifylline, simvastatin, tamoxifen, or losartan when compared with the PF group. However, the volumes of the collagen bundles and vessels as well as the population of fibroblasts remained at the control level or even lower in PF plus pentoxifylline, simvastatin, tamoxifen, and losartan groups. This indicated the anti-fibrotic effects of the four drugs. It can be concluded that pentoxifylline, simvastatin, tamoxifen, and losartan could reduce fibrosis activities by minimizing the formation of collagen bundles and vessels as well as decreasing the population of fibroblasts 8 weeks after PF. Yet, losartan brought about a better outcome compared with the other chemicals.

Normal and keloid fibroblasts are differentially influenced by IFN-γ and triamcinolone as well as by their combination

Impaired wound healing as well as imbalanced cell proliferation and extracellular matrix synthesis and degeneration can cause aberrant scarring. The most severe impacts of such scarring on patients' lives are stigmatization and physical restriction. Although, a broad variety of combinatorial approaches with, e.g., glucocorticoids, chemotherapeutics, and immunomodulators are used, there is still a high recurrence rate of keloids. The aim of this study was to investigate which influence interferon γ (IFN-γ, 1.000-10.000 IU/mL) and/or triamcinolone acetonide (TA, 1 μg/mL) have on proliferation, cell viability, collagen type I synthesis, and cytokine secretion in healthy and keloid fibroblasts. It was shown that mono-treatment with IFN-γ or TA for 2 days induced a severe reduction of the proliferative potential in both cell species. The combinatory treatment (IFN-γ plus TA) of keloid fibroblasts enhanced the anti-proliferative effect of the mono-treatments, whereas no additional anti-proliferative effect was observed in normal fibroblasts. Furthermore, we observed that the combinatory treatment regimen reduced the expression of α-smooth muscle actin (α-SMA), an actin isotype contributing to cell-generated mechanical tension, in keloid fibroblasts. In normal fibroblasts, α-SMA was reduced by the mono-treatment with IFN-γ as well as by the combinatory treatment. The analysis of collagen-type I synthesis revealed that TA did not reduce collagen type I synthesis in normal fibroblasts but in keloid fibroblasts. IFN-γ reduced in both cell species the collagen type I synthesis. The combination of TA and IFN-γ intensified the previously observed collagen type I synthesis reduction in keloid fibroblasts. The herein presented data suggest the combinatory application of IFN-γ and TA as a promising therapy concept for keloids.

Multi-dimensional models for functional testing of keloid scars: In silico, in vitro, organoid, organotypic, ex vivo organ culture, and in vivo models

Keloid scars are described as benign fibro-proliferative dermal outgrowths that commonly occur in pigmented skin post cutaneous injury, and continue to grow beyond the boundary of the original wound margin. There is a lack of thorough understanding of keloid pathogenesis and thus keloid therapeutic options remain ill-defined. In view of the poor response to current therapy and high recurrence rates, there is an unmet need in improving our knowledge and therefore in identifying targeted and effective treatment strategies in management of keloids. Keloid research however, is hampered by a lack of relevant animal models as keloids do not spontaneously occur in animals and are unique to human skin. Therefore, developing novel animal models and nonanimal models for functional evaluation of keloid cells and tissue for better understanding their pathobiology and response to putative candidate therapies are essential. Here, we present the key concepts and relevant emerging research on two-dimensional and three-dimensional cell and tissue models for functional testing of keloid scars. We will describe in detail current models including in vitro mono- and co-cultures, multi-cellular spheroids (organoids) and organotyopic cultures, ex vivo whole skin keloid tissue organ culture models as well as in vivo human patient models. Finally, we discuss the role played by time as the fourth dimension in a novel model that involves sequential temporal biopsies of human patients with keloids (a so called 4D in vivo human model). The use of these unique models will no doubt prove pivotal in identification of new drug targets as well as biomarkers, in functional testing of emerging novel therapeutics, and in enhancing our understanding of keloid disease biology.

Simvastatin and the Rho-kinase inhibitor Y-27632 prevent myofibroblast transformation in Peyronie's disease-derived fibroblasts via inhibition of YAP/TAZ nuclear translocation

OBJECTIVES

To uncover the anti-myofibroblast (MFB) properties of Rho-kinase inhibitor (compound Y-27632) and simvastatin in an in vitro model of Peyronie's disease (PD), a sexually debilitating disease caused by an irreversible fibrotic plaque in the penile tunica albuginea (TA).

MATERIALS AND METHODS

Primary human fibroblasts (FBs) were isolated from surgically obtained TA tissue from patients with PD. To induce MFB status, cells were stimulated with 3 ng/mL transforming growth factor-β1 (TGF-β1). Increasing doses of Y-27632 and simvastatin were added. Real-time quantitative PCR was used to assess mRNA expression of α-smooth muscle actin (α-SMA), collagen III, elastin and connective tissue growth factor (CTGF) after 72 h. Western blot analysis was used to quantify α-SMA protein contents, and immunofluorescence (IF) was used to visualize MFB differentiation by staining for α-SMA after 72 h. A resazurin-based assay was used to assess cell viability to ensure the anti-MFB effect of the drugs. A mechanistic study was performed using IF staining for YAP/TAZ nuclear translocation.

RESULTS

After 72 h of stimulation with TGF-β1, a six- to 10-fold upregulation of α-SMA could be observed. When treated with Y-27632 or simvastatin, the α-SMA, collagen III, elastin and CTGF mRNA expression was impeded. Additionally, TGF-β1 stimulation showed a twofold increase in α-SMA protein expression, which was reversed to non-stimulated levels after treatment with Y-27632 and simvastatin. Using IF, stimulated cells were identified as MFB (α-SMA+, Vim+) as opposed to the non-stimulated, Y-27632- and simvastatin-treated cells (α-SMA-, Vim+). The resazurin-based assay confirmed that the cell viability was not compromised by the administered drugs. On stimulation with TGF-β1, nuclear translocation of YAP/TAZ could be observed, which was prevented by adding the aforementioned compounds.

CONCLUSION

Transformation of FBs into the contractile and extracellular matrix-producing MFBs occurs after TGF-β1 stimulation. In our experiments, Rho-kinase inhibition and simvastatin treatment were shown to prevent this in TGF-β1-stimulated cells on an RNA and protein level through the inhibition of YAP/TAZ nuclear translocation. Y-27632 and simvastatin could become a novel treatment option in the early treatment of PD.

Unique behavior of dermal cells from regenerative mammal, the African Spiny Mouse, in response to substrate stiffness

The African Spiny Mouse (Acomys spp.) is a unique outbred mammal capable of full, scar-free skin regeneration. In vivo, we have observed rapid reepithelialization and deposition of normal dermis in Acomys after wounding. Acomys skin also has a lower modulus and lower elastic energy storage than normal lab mice, Mus musculus. To see if the different in vivo mechanical microenvironments retained an effect on dermal cells and contributed to regenerative behavior, we examined isolated keratinocytes in response to physical wounding and fibroblasts in response to varying substrate stiffness. Classic mechanobiology paradigms suggest stiffer substrates will promote myofibroblast activation, but we do not see this in Acomys dermal fibroblasts (DFs). Though Mus DFs increase organization of α-smooth muscle actin (αSMA)-positive stress fibers as substrate stiffness increases, Acomys DFs assemble very few αSMA-positive stress fibers upon changes in substrate stiffness. Acomys DFs generate lower traction forces than Mus DFs on pliable surfaces, and Acomys DFs produce and modify matrix proteins differently than Mus in 2D and 3D culture systems. In contrast to Acomys DFs "relaxed" behavior, we found that freshly isolated Acomys keratinocytes retain the ability to close wounds faster than Mus in an in vitro scratch assay. Taken together, these preliminary observations suggest that Acomys dermal cells retain unique biophysical properties in vitro that may reflect their altered in vivo mechanical microenvironment and may promote scar-free wound healing.

A Potential Link Between Oxidative Stress and Endothelial-to-Mesenchymal Transition in Systemic Sclerosis

Systemic sclerosis (SSc), an autoimmune disease that is associated with a number of genetic and environmental risk factors, is characterized by progressive fibrosis and microvasculature damage in the skin, lungs, heart, digestive system, kidneys, muscles, joints, and nervous system. These abnormalities are associated with altered secretion of growth factor and profibrotic cytokines, such as transforming growth factor-beta (TGF-β), interleukin-4 (IL-4), platelet-derived growth factor (PDGF), and connective-tissue growth factor (CTGF). Among the cellular responses to this proinflammatory environment, the endothelial cells phenotypic conversion into activated myofibroblasts, a process known as endothelial to mesenchymal transition (EndMT), has been postulated. Reactive oxygen species (ROS) might play a key role in SSs-associated fibrosis and vascular damage by mediating and/or activating TGF-β-induced EndMT, a phenomenon that has been observed in other disease models. In this review, we identified and critically appraised published studies investigating associations ROS and EndMT and the presence of EndMT in SSc, highlighting a potential link between oxidative stress and EndMT in this condition.

TGF-β and CTGF are Mitogenic Output Mediators of Wnt/β-Catenin Signaling in Desmoid Fibromatosis

Desmoid fibromatosis is a locally aggressive clonal fibroblastic proliferation with high recurrence rates and no metastatic potential. Implicated molecular aberrations occur within the Wnt/β-catenin pathway (APC and β-catenin gene mutations). Transforming growth factor-β (TGF-β) and connective tissue growth factor (CTGF) are profibrotic growth factors, downstream from nuclear translocation of β-catenin, that lead to increased fibrogenesis. CTGF (a downstream effector of TGF-β) is a matricellular protein that modulates the activity of growth factors, adhesion molecules, integrins, and extracellular matrix thus playing a central role in tissue remodeling and fibrosis. Recently there has been growing interest in use of extracellular matrix inhibitors for treatment of various fibrogenic diseases. Desmoid fibromatosis samples (n=15) were evaluated for expression of β-catenin, TGF-β, and CTGF using immunohistochemistry on formalin paraffin-embedded material. A control group comprising scar tissue and adjacent normal skin (n=10) were simultaneously immunostained with above mentioned markers. Real-time polymerase chain reaction was performed on frozen specimens of desmoid fibromatosis (n=6) and normal skin (n=2). All 15 desmoid tumors were positive for β-catenin (surrogate marker of Wnt/β-catenin pathway dysregulation) which was negative in control normal skin and scar samples. TGF-β and CTGF were negative in 9 of 10 normal skin controls. TGF-β and CTGF were positive in all cases of scar tissue. All 15 cases of desmoid tumors were positive for TGF-β and CTGF. The real-time polymerase chain reaction showed higher expression levels of TGF-β and CTGF in desmoid fibromatosis compared with normal skin. The high constitutive expression of β-catenin downstream effectors; TGF-β, CTGF has the potential for enabling targeted therapy.

Simvastatin and nanofibrous poly(l-lactic acid) scaffolds to promote the odontogenic potential of dental pulp cells in an inflammatory environment

In this study, we investigated the anti-inflammatory, odontogenic and pro-angiogenic effects of integrating simvastatin and nanofibrous poly(l-lactic acid) (NF-PLLA) scaffolds on dental pulp cells (DPCs). Highly porous NF-PLLA scaffolds that mimic the nanofibrous architecture of extracellular matrix were first fabricated, then seeded with human DPCs and cultured with 0.1 μM simvastatin and/or 10 μg/mL pro-inflammatory stimulator lipopolysaccharide (LPS). The gene expression of pro-inflammatory mediators (TNF-α, IL-1β and MMP-9 mRNA) and odontoblastic markers (ALP activity, calcium content, DSPP, DMP-1 and BMP-2 mRNA) were quantified after long-term culture in vitro. In addition, we evaluated the scaffold's pro-angiogenic potential after 24 h of in vitro co-culture with endothelial cells. Finally, we assessed the combined effects of simvastatin and NF-PLLA scaffolds in vivo using a subcutaneous implantation mouse model. The in vitro studies demonstrated that, compared with the DPC/NF-PLLA scaffold constructs cultured only with pro-inflammatory stimulator LPS, adding simvastatin significantly repress the expression of pro-inflammatory mediators. Treating LPS+ DPC/NF-PLLA constructs with simvastatin also reverted the negative effects of LPS on expression of odontoblastic markers in vitro and in vivo. Western blot analysis demonstrated that these effects were related to a reduction in NFkBp65 phosphorylation and up-regulation of PPARγ expression, as well as to increased phosphorylation of pERK1/2 and pSmad1, mediated by simvastatin on LPS-stimulated DPCs. The DPC/NF-PLLA constructs treated with LPS/simvastatin also led to an increase in vessel-like structures, correlated with increased VEGF expression in both DPSCs and endothelial cells. Therefore, the combination of low dosage simvastatin and NF-PLLA scaffolds appears to be a promising strategy for dentin regeneration with inflamed dental pulp tissue, by minimizing the inflammatory reaction and increasing the regenerative potential of resident stem cells.

STATEMENT OF SIGNIFICANCE

The regeneration potential of stem cells is dependent on their microenvironment. In this study, we investigated the effect of the microenvironment of dental pulp stem cells (DPSCs), including 3D structure of a macroporous and nanofibrous scaffold, the inflammatory stimulus lipopolysaccharide (LPS) and a biological molecule simvastatin, on their regenerative potential of mineralized dentin tissue. The results demonstrated that LPS upregulated inflammatory mediators and suppressed the odontogenic potential of DPSCs. Known as a lipid-lowing agent, simvastatin was excitingly found to repress the expression of pro-inflammatory mediators, up-regulate odontoblastic markers, and exert a pro-angiogenic effect on endothelial cells, resulting in enhanced vascularization and mineralized dentin tissue regeneration in a biomimetic 3D tissue engineering scaffold. This novel finding is significant for the fields of stem cells, inflammation and dental tissue regeneration.

Ginsenoside Rg3 inhibits keloid fibroblast proliferation, angiogenesis and collagen synthesis in vitro via the TGF‑β/Smad and ERK signaling pathways

A wide range of therapeutic options exists for the treatment of keloids, all of which have their own strengths; however, a high risk of side-effects and frequent recurrence remains. Therefore, the present study aimed to identify improved therapeutic approaches or drugs for the treatment of keloids. Ginsenoside Rg3 (Rg3) has been reported to exert numerous antitumor effects, thus indicating that Rg3 may be a potential therapeutic agent that targets keloids. The present study determined the effects of Rg3 on human keloid fibroblasts (KFs) in vitro, and further explored the associated molecular and cellular mechanisms. Keloid scar specimens were obtained from patients, aged between 22 and 35 years, without systemic diseases and primary cells were isolated from keloid tissues. In each assay, KFs were divided into three groups and were cultured in medium with or without various concentrations of Rg3 (50 or 100 μg/ml). Cell viability assay, flow cytometry, quantitative polymerase chain reaction, cell migration assay, immunofluorescence staining, western blot analysis, Transwell cell invasion assay and immunohistochemical analysis were used to analyze the KFs and keloid explant cultures. The results of the present study demonstrated that Rg3 was able to exert an inhibitory effect on the transforming growth factor-β/Smad and extracellular signal-regulated kinase signaling pathways in KFs. The proliferation, migration, invasion, angiogenesis and collagen synthesis of KFs were markedly suppressed following treatment with Rg3. Furthermore, the results of an ex vivo assay indicated that Rg3 inhibited angiogenesis and reduced collagen accumulation in keloids. Significant statistical differences existed between the control and Rg3-treated groups (P<0.05). All of these experimental results suggested that Rg3 may serve as a reliable drug for the treatment of patients with keloids.

Knockdown of elF3a inhibits TGF‑β1‑induced extracellular matrix protein expression in keloid fibroblasts

Keloid formation is characterized by hyperproliferation of secretory and responsive keloid fibroblasts (KFs) and overproduction of extracellular matrix (ECM). Eukaryotic translation initiation factor 3 subunit A (eIF3a) one of the core subunits of the translation initiation complex, eIF3, has previously been reported to possess an anti‑fibrogenic effect. However, the role of eIF3a in keloid formation has not yet been investigated. Therefore, the present study examined the effect of eIF3a on transforming growth factor‑β1 (TGF‑β1)‑mediated ECM expression in KFs. The expression levels of eIF3a in human keloid tissues was evaluated using reverse transcription‑quantitative polymerase chain reaction and western blotting. KFs were incubated with siRNA‑eIF3a or siRNA‑mock for 48 h. The cells were then treated with TGF‑β1 (10 ng/ml) for 72 h. Cell proliferation was evaluated using the CCK‑8 assay. The expression levels of α‑SMA, collagen type I, TGF‑β receptor I (RI), TGF‑β RII, phosphorylated (p)‑mothers against decapentaplegic homolog (Smad2), Smad2, p‑Smad3 and Smad3 were detected western blotting. The present study identified significant upregulation of eIF3a mRNA and protein and in human keloid tissues compared with in normal tissues. Knockdown of eIF3a inhibited KF proliferation induced by TGF‑β1. In addition, eIF3a silencing significantly suppressed the TGF‑β1‑induced expression of α‑smooth muscle actin, collagen I, TGF‑β RI and TGF‑β RII in KFs. Furthermore, eIF3a silencing inhibited the phosphorylation levels of Smad2 and Smad3 in TGF‑β1‑induced KFs. To the best of our knowledge, the current study is the first to demonstrate that siRNA‑eIF3a inhibits the expression ECM proteins via the TGF‑β1/Smad signaling pathway in KFs. Therefore, eIF3a may be a potential, novel target for treatment of keloids.

Statins reduce TGF-beta2-modulation of the extracellular matrix in cultured astrocytes of the human optic nerve head

Statins are cholesterol lowering drugs and have shown beneficial effects on glaucoma. With regard to the mechanism of statin action on glaucoma, we investigated the effects of statins on transforming growth factor-beta 2 (TGF-β2)-induced expression of extracellular matrix (ECM) proteins in human astrocytes of the optic nerve head (ONH) lamina cribrosa (LC). By using primary human ONH astrocytes, we found that both simvastatin and lovastatin inhibited TGF-β2-mediated expression of ECM proteins such as connective tissue growth factor, collagen I, fibronectin, and plasminogen activator inhibitor-1. Suppression of ECM related proteins is due to inhibition of Smad2/3 activation as statins inhibit TGF-β2-induced Smad2 phosphorylation and Smad2/3 nuclear accumulation. In ONH astrocytes, TGF-β2 does not induce MAPK activation. In this study we found an anti-fibrotic effect of statins in human astrocytes of the ONH and identified TGF-β2 as a mediator of statin action, which may support a beneficial role for statins in blocking glaucomatous axonal damage induced by ECM remodeling.

Biological Differences between Hanwoo longissimus dorsi and semimembranosus Muscles in Collagen Synthesis of Fibroblasts

Variations in physical toughness between muscles and animals are a function of growth rate and extend of collagen type I and III. The current study was designed to investigate the ability of growth rate, collagen concentration, collagen synthesizing and degrading genes on two different fibroblast cells derived from Hanwoo m. longissimus dorsi (LD) and semimembranosus (SM) muscles. Fibroblast cell survival time was determined for understanding about the characteristics of proliferation rate between the two fibroblasts. We examined the collagen concentration and protein expression of collagen type I and III between the two fibroblasts. The mRNA expression of collagen synthesis and collagen degrading genes to elucidate the molecular mechanisms on toughness and tenderness through collagen production between the two fibroblast cells. From our results the growth rate, collagen content and protein expression of collagen type I and III were significantly higher in SM than LD muscle fibroblast. The mRNA expressions of collagen synthesized genes were increased whereas the collagen degrading genes were decreased in SM than LD muscle. Results from confocal microscopical investigation showed increased fluorescence of collagen type I and III appearing stronger in SM than LD muscle fibroblast. These results implied that the locomotion muscle had higher fibroblast growth rate, leads to produce more collagen, and cause tougher than positional muscle. This in vitro study mirrored that background toughness of various muscles in live animal is likely associated with fibroblast growth pattern, collagen synthesis and its gene expression.

Local Application of Statins Significantly Reduced Hypertrophic Scarring in a Rabbit Ear Model

BACKGROUND

We previously showed that intradermal injection of statins is a successful treatment for hypertrophic scarring. Topical application has many advantages over intradermal injection. In this study, we demonstrate the efficacy of topical statin treatment in reducing scar in our validated rabbit ear scar model.

METHODS

Twenty New Zealand White rabbits were divided into 2 study groups, with 6 rabbits receiving 10 μm pravastatin intradermally at postoperative days 15, 18, and 21, and 14 rabbits receiving 0.4%, 2%, and 10% simvastatin topical application at postoperative days 14-25. Four or 6 full-thickness circular dermal punches 7 mm in diameter were made on the ventral surface of the ear down to but not including the perichondrium. Specimens were collected at 28 days to evaluate the effects of statins on hypertrophic scarring.

RESULTS

Treatment with pravastatin intradermal administration significantly reduced scarring in terms of scar elevation index. Topical treatment with both medium- and high-dose simvastatin also significantly reduced scarring. High-dose simvastatin topical treatment showed a major effect in scar reduction but induced side effects of scaling, erythema, and epidermal hyperplasia, which were improved with coapplication of cholesterol. There is a dose response in scar reduction with low-, medium- and high-dose simvastatin topical treatment. High-dose simvastatin treatment significantly reduced the messenger ribonucleic acid (mRNA) expression of connective tissue growth factor, consistent with our previously published work on intradermally injected statins. More directly, high-dose simvastatin treatment also significantly reduced the mRNA expression of collagen 1A1.

CONCLUSIONS

Topical simvastatin significantly reduces scar formation. The mechanism of efficacy for statin treatment through interference with connective tissue growth factor mRNA expression was confirmed.

BMP‑7 suppresses excessive scar formation by activating the BMP‑7/Smad1/5/8 signaling pathway

Scarring is the inevitable consequence of wound repair, which may cause significant physical and mental pain to patients when excessive. Bone morphogenetic protein-7 (BMP-7) has been proved to inhibit TGF-β-induced fibrosis in various tissues including dermal papilla cells. However, the effect of BMP-7 on hypertrophic scarring, a common proliferative disorder of dermal fibroblasts, has not been determined. To overcome this problem, the present study established a mouse model of thermal injury to investigate the inhibitory effects of BMP-7 on scar formation. The histological analysis of scar tissues was performed by H&E and Masson's trichrome staining. Western blot assay was used to determine the level changes of related proteins and TUNEL assay was performed to assess the apoptosis of scar tissues. The results demonstrated that BMP-7 promoted wound healing and inhibited scar formation when compared with untreated mice. Collagen deposition and the expression of fibrotic proteins were suppressed in the scar tissues of mice treated with BMP-7. In addition, BMP-7 induced fibroblast apoptosis in scar tissues. Furthermore, activation of the BMP-7/Smad1/5/8 signaling pathway may have been involved in the inhibitory effects of BMP-7 on scar formation. In conclusion, the results of the present study indicate that BMP-7 may inhibit excessive scar formation via activation of the BMP-7/Smad1/5/8 signaling pathway. The results present a potential alternative therapeutic strategy for the treatment of hypertrophic scarring.

Fibroblast Growth Factor-1 Suppresses TGF-β-Mediated Myofibroblastic Differentiation of Rat Hepatic Stellate Cells

Myofibroblast expansion is a critical event in the pathogenesis of liver fibrosis. The activation of hepatic stellate cells (HSC) to myofibroblast (MFB) results in the enhanced production of extracellular matrix (ECM). In this study, we explored the effect of acidic fibroblast growth factor (FGF-1) treatment on a transforming growth factor (TGF-β1) induced MFB conversion. We used HSC-T6 cell line, which represents well-established model of activated HSC. These cells strongly expressed α-smooth muscle actin (α-SMA) and fibronectin (FN-EDA) after stimulation with TGF-β1, which is a stimulus for MFB differentiation and ECM production. FGF-1 reduced proteins expression to levels comparable with untreated cells. Mild repression of secreted gelatinases was seen in culture media after FGF-1 treatment. The exposure of cells to collagen gel leads to changes in cell morphology and in expression of MFB markers. Lack of α-SMA in cells embedded to collagen gel was detected. When stimulated with TGF-β1, the cells increased expression of FN-EDA, but not α-SMA. Although the cells on plastic and in collagen gel show different properties, FGF-1 reduced expression of FN-EDA in both conditions. Disrupting TGF-β1 signalling pathway represents a potential strategy for the treatment of fibrosis. We showed that FGF-1 could antagonize signals initiated by TGF-β1.

The Role of the Rho/ROCK Pathway in Ang II and TGF-β1-Induced Atrial Remodeling

Objectives

To study the role of the Rho/ROCK pathway in Ang II and TGF-β1-induced atrial remodeling.

Methods and Results

A canine atrial fibrillation (AF) model was established by rapid atrial pacing (RAP) of the left atrium. The roles of TGF-β1, the RhoA/ROCK signaling pathway and connective tissue growth factor (CTGF) in atrial remodeling were studied via both in vitro and in vivo experiments. Each of the dogs that received RAP developed persistent AF within 4 weeks. The mRNA expression levels of TGF-β1 (1.32±0.38), Collagen-I(1.33±0.91), CTGF(5.83±3.71), RhoA(1.23±0.57) and ROCK-1 (1.02±0.27) in the left atrium were significantly increased following 4 weeks of RAP. Angiotensin II (Ang II) induced the proliferation of atrial fibroblasts and up-regulated the expression of both CTGF and ROCK-1 in a dose-dependent manner. Simvastatin and Y27632 reversed Ang II-induced CFs proliferation, as well as ROCK-1(0.89±0.05 and 1.27±0.03, respectively) and CTGF (0.87±0.04 and 0.91±0.02, respectively) expression. The expression mRNA of ROCK-1(1.74±0.13) and CTGF (2.28±0.11) can upregulated by TGF-β1, and down-regulated by Simvastatin (1.22±0.03 vs 2.27±0.11), Y27632 (1.01±0.04 vs 1.64±0.03), Los (1.04±0.11 vs 1.26±0.05), respectively. Losartan and Simvastatin attenuated the effects of TGF-β1, inhibited RhoA activity as opposed to RhoA protein expression. Y27632 had no effect on either the expression or the activity of RhoA.

Conclusions

The increased expression of profibrotic factors (CTGF, ROCK1 and Smad2/3) played an important role in our RAP-induced AF model. Increased atrial profibrotic factors involve the activation of either the TGF-β1/RhoA/ROCK-1 or the TGF-β1/Smad2/3 signaling pathway.

Parenchyma-stromal interactions induce fibrosis by secreting CCN2 and promote osteoclastogenesis by stimulating RANKL and CD68 through activated TGF-β/BMP4 in ameloblastoma

BACKGROUND

Tumor parenchyma-stromal interactions affect the properties of tumors and their dynamics. Our group previously showed that secreted frizzled related protein (sFRP)-2 impairs bone formation and promotes bone invasion in ameloblastoma. However, the effects of the secreted growth factors CCN2, TGF-β, and BMP4 on stromal tissues in ameloblastoma remain unclear.

MATERIALS AND RESULTS

Thirty-five paraffin-embedded ameloblastoma cases, ameloblastoma-derived cell lines (AM-1), and primary cultures of ameloblastoma stromal fibroblasts (ASF) were used. Immunohistochemistry, MTT assay, Western blotting, and RT-PCR were performed on these samples. Parenchyma-stromal CCN2 overexpression correlated significantly with fibrous-type stroma, but not with myxoid-type stroma, suggesting a role of CCN2 in fibrosis (P < 0.05). Recombinant CCN2 induction of enhanced ASF proliferation in AM-1 medium supports this view. Conversely, BMP4 and TGF-β were expressed in myxoid-type fibroblasts, but little expression was found in parenchyma. RANKL-positive and CD68-positive stromal cell populations were significantly greater in myxoid-type tumor areas than in fibrous-type tumor areas, while a higher Ki-67 labeling index was recorded in ameloblastoma with fibrous-type stroma. These data suggest that stromal properties influence bone resorption-related activities and growth rates, respectively.

CONCLUSIONS

These results suggest that the effects of secreted growth factors are governed by ameloblastoma parenchyma-stromal interactions. CCN2 promotes fibrogenesis independent of TGF-β signaling. Absence of CCN2 expression is associated with a phenotypic switch to a myxoid-type microenvironment that is conducive for TGF-β/BMP4 signaling to promote osteoclastogenesis.

Role of RhoA in occurrence and development of liver fibrosis

Liver fibrosis is a pathophysiologic process resulting from a variety of chronic liver injuries, characterized by the excessive accumulation of extracellular matrix or the formation of scar. The transdifferentiation from quiescent hepatic stellate cells (HSCs) or portal fibroblasts (PFs) to activated myofibroblasts (MFBs) is a key step of producing extracellular matrix. RhoA can regulate the cell cytoskeleton and is involved in activating HSCs/PFs, thus having a significant fibrogenic effect. In this paper, we review the recent advances in understanding the role of RhoA in the occurrence and development of liver fibrosis.

RhoA Ambivalently Controls Prominent Myofibroblast Characteritics by Involving Distinct Signaling Routes

Introduction

RhoA has been shown to be beneficial in cardiac disease models when overexpressed in cardiomyocytes, whereas its role in cardiac fibroblasts (CF) is still poorly understood. During cardiac remodeling CF undergo a transition towards a myofibroblast phenotype thereby showing an increased proliferation and migration rate. Both processes involve the remodeling of the cytoskeleton. Since RhoA is known to be a major regulator of the cytoskeleton, we analyzed its role in CF and its effect on myofibroblast characteristics in 2 D and 3D models.

Results

Downregulation of RhoA was shown to strongly affect the actin cytoskeleton. It decreased the myofibroblast marker α-sm-actin, but increased certain fibrosis-associated factors like TGF-β and collagens. Also, the detailed analysis of CTGF expression demonstrated that the outcome of RhoA signaling strongly depends on the involved stimulus. Furthermore, we show that proliferation of myofibroblasts rely on RhoA and tubulin acetylation. In assays accessing three different types of migration, we demonstrate that RhoA/ROCK/Dia1 are important for 2D migration and the repression of RhoA and Dia1 signaling accelerates 3D migration. Finally, we show that a downregulation of RhoA in CF impacts the viscoelastic and contractile properties of engineered tissues.

Conclusion

RhoA positively and negatively influences myofibroblast characteristics by differential signaling cascades and depending on environmental conditions. These include gene expression, migration and proliferation. Reduction of RhoA leads to an increased viscoelasticity and a decrease in contractile force in engineered cardiac tissue.

Activation of AMPK by metformin inhibits TGF-β-induced collagen production in mouse renal fibroblasts

AIMS

To clarify whether activation of adenosine monophosphate-activated protein kinase (AMPK) by metformin inhibits transforming growth factor beta (TGF-β)-induced collagen production in primary cultured mouse renal fibroblasts and further to address the molecular mechanisms.

MAIN METHODS

Primary cultured mouse renal fibroblasts were stimulated with TGF-β1 and the sequence specific siRNA of Smad3 or connective tissue growth factor (CTGF) was applied to investigate the involvement of these molecular mediators in TGF-β1-induced collagen type I production. Cells were pre-incubated with AMPK agonist metformin or co-incubated with AMPK agonist metformin and AMPK inhibitor Compound C before TGF-β1 stimulation to clarify whether activation of AMPK inhibition of TGF-β1-induced renal fibroblast collagen type I expression.

KEY FINDINGS

Our results demonstrate that TGF-β1 time- and dose-dependently induced renal fibroblast collagen type I production; TGF-β1 also stimulated Smad3-dependent CTGF expression and caused collagen type I generation; this effect was blocked by knockdown of Smad3 or CTGF. Activation of AMPK by metformin reduced TGF-β1-induced collagen type I production by suppression of Smad3-driven CTGF expression.

SIGNIFICANCE

This study suggests that activation of AMPK might be a novel strategy for the treatment of chronic kidney disease (CKD) partially by inhibition of renal interstitial fibrosis (RIF).