HSP47 is a useful marker for skin fibroblasts in formalin-fixed, paraffin-embedded tissue specimens

Mineralocorticoid receptor expression and the effects of the mineralocorticoid receptor antagonist spironolactone in a murine model of graft-versus-host disease

PURPOSE

The topical administration of spironolactone, a mineralocorticoid receptor antagonist (MRA) improves dry eye symptoms in patients with ocular graft-versus-host disease (GVHD); however, the detailed mechanism remains unclear. This study aimed to investigate the effects of spironolactone eyedrops on the ocular surface using a chronic GVHD (cGVHD) mouse model and to determine the expression of the mineralocorticoid receptor (MR).

METHODS

A cGVHD mouse model was established by allogeneic bone marrow transplantation (BMT) from B10.D2 mice to BALB/c mice. Subsequently, cGVHD mice were treated with either 0.005 % spironolactone or vehicle eyedrops. The eyelids, cornea and conjunctiva of the recipients were analyzed at 4-week intervals post-BMT in both groups.

RESULTS

Signs of ocular GVHD, such as corneal epithelial damage, depletion of meibomian glands, and inflammatory cell infiltration onto the ocular surface, were significantly decreased in cGVHD mice treated with spironolactone eyedrops. The expression of the MR NR3C2 in the corneal and conjunctival epithelia was significantly increased in cGVHD mice. HSP47+NR3C2+ MR-expressing fibroblasts, CD45+NR3C2+ MR-expressing leukocytes, and CD4+NR3C2+ MR-expressing T cells infiltrated the ocular surface tissue of cGVHD mice significantly more than that of syngeneic controls.

CONCLUSIONS

MR expression is increased in epithelial cells, fibroblasts, and T cells in a murine cGVHD model, whereas MRA and spironolactone eyedrops could attenuate the severity of ocular GVHD. These findings suggest that MR signaling partially contributes to the development of ocular GVHD in this mouse model.

Specific localization of fibroblasts at the intercalated duct in the major salivary glands of rats

OBJECTIVES

Immunohistochemical methods were employed to investigate the morphological heterogeneity and localization of fibroblasts associated with the function of major salivary glands in rats.

METHODS

Histochemical and electron microscopic observations were made in rat parotid, submandibular, and sublingual glands and pancreas. Fibroblasts were immunostained using their specific marker, 47 kDa heat shock protein (Hsp47).

RESULTS

Hsp47-immunopositive fibroblasts within the intralobular connective tissue exhibited a notably smaller size compared with the interlobular connective tissue. They were loosely distributed throughout the connective tissue. However, fibroblasts with elongated long processes were explicitly identified at the intercalated ducts in parotid, sublingual, and submandibular glands. Fibroblastic bodies and processes were tightly approximated with the basement membrane of the duct. Electron microscopy confirmed these findings, revealing a thin layer consisting of collagen fibers was found between the fibroblasts and the basement membrane. Double staining of Hsp47 and α-smooth muscle actin (αSMA) in parotid glands indicating that Hsp47-positive fibroblasts enveloped both the duct and αSMA-positive myoepithelial cells. Additionally, They projected long and thin processes longitudinally at the straight portion or circularly at the bifurcated portion of the duct. The three-dimensional reconstruction showed a frame-like structure of fibroblasts surrounding the intercalated duct with longitudinal myoepithelial cells. However, such specific localization of fibroblasts was not detected in the exocrine pancreas lacking myoepithelium.

CONCLUSIONS

Small fibroblasts with long processes connecting or overwrapping each other and thin collagen layers surround the intercalated ducts in rat major salivary glands, presumably contributing to protecting the ducts from salivary flow and myoepithelial contraction.

Expression of HSP70 in Human Skin After Cryolipolysis Treatment

BACKGROUND

Cryolipolysis nonsurgically targets and reduces subcutaneous fat through controlled cooling of skin and underlying fatty tissue. Although skin changes after cryolipolysis treatment have been observed clinically, the mechanisms by which these occur are not well understood.

OBJECTIVES

The aim of this study was to investigate the expression of heat shock protein 70 (HSP70) in the epidermal and dermal layers of human skin following cryolipolysis treatment.

METHODS

Subjects (N = 11; average age, 41.8 years; average BMI, 29.59 kg/m2) were recruited to receive cryolipolysis treatment with a vacuum cooling cup applicator (-11°C/35 minutes) prior to abdominoplasty surgery. Treated and untreated abdominal tissue samples were harvested immediately after surgery (average follow-up, 15 days; range, 3 days to 5 weeks). Immunohistochemistry for HSP70 was performed on all samples. Slides were digitized and quantified in epidermal and dermal layers.

RESULTS

There was higher epidermal and dermal HSP70 expression in cryolipolysis-treated pre-abdominoplasty samples vs untreated samples. There was a 1.32-fold increase of HSP70 expression in the epidermis (P < .05) and a 1.92-fold increase in the dermis (P < .04) compared with untreated samples.

CONCLUSIONS

We found significant induction of HSP70 after cryolipolysis treatment in epidermal and dermal layers. HSP70 has potential therapeutic benefits and is recognized to have a role in skin protection and adaption after thermal stress. Although cryolipolysis is popular for subcutaneous fat reduction, cryolipolytic HSP induction in the skin may prove valuable for additional therapeutic applications, including skin wound healing, remodeling, rejuvenation, and photoprotection.

LEVEL OF EVIDENCE: 4

Role of Subcutaneous Adipose Tissues in the Pathophysiology of Secondary Lymphedema

Background: Secondary lymphedema (LE) occurs due to the disruption of lymphatic circulation. Lymphatic fluid accumulation in subcutaneous tissues induces adipocyte proliferation. Obesity is an important risk factor for the occurrence and deterioration of LE. Although the relationship between LE and subcutaneous adipose tissue increase has been reported clinically, their pathophysiological relationship remains unknown. Thus, we aimed to verify whether subcutaneous adipose tissue increase is involved in the pathophysiology of secondary LE. Methods and Results: The hindlimb model of secondary LE was created using male Sprague-Dawley rats (control and LE groups; n = 5 each). Skin samples were obtained on postoperative day 168. Histological examination and quantitative real-time polymerase chain reaction analysis of inflammatory adipokines, tumor necrosis factor-alpha (Tnf-α), C-C chemokine ligand 2 (Ccl2), and interleukin-6 (Il-6) were performed. Limb volume and subcutaneous adipose tissues significantly increased in the LE group compared with those in the control. Macrophages aggregated in the augmented adipose tissues, around the adipocytes, and formed crown-like structures (CLSs). The number of CLSs significantly increased in the LE group. These macrophages expressed transforming growth factor-beta 1 (TGF-β1). Inflammatory adipokine secretion was not observed. Although Il-6 expression increased in the LE group, IL-6 was expressed in subcutaneous myofibroblasts but not in subcutaneous adipocytes. Conclusion: As TGF-β1 derived from subcutaneous myofibroblasts is involved in skin fibrosis during LE, TGF-β1 derived from adipose tissues may also play a similar role. Drug treatment for subcutaneous adipose tissue reduction may improve the skin condition in secondary LE and may be a new therapeutic strategy.

Optimization of an Ex-Vivo Human Skin/Vein Model for Long-Term Wound Healing Studies: Ground Preparatory Activities for the 'Suture in Space' Experiment Onboard the International Space Station

This study is preliminary to an experiment to be performed onboard the International Space Station (ISS) and on Earth to investigate how low gravity influences the healing of sutured human skin and vein wounds. Its objective was to ascertain whether these tissue explants could be maintained to be viable ex vivo for long periods of time, mimicking the experimental conditions onboard the ISS. We developed an automated tissue culture chamber, reproducing and monitoring the physiological tensile forces over time, and a culture medium enriched with serelaxin (60 ng/mL) and (Zn(PipNONO)Cl) (28 ng/mL), known to extend viability of explanted organs for transplantation. The results show that the human skin and vein specimens remained viable for more than 4 weeks, with no substantial signs of damage in their tissues and cells. As a further clue about cell viability, some typical events associated with wound repair were observed in the tissue areas close to the wound, namely remodeling of collagen fibers in the papillary dermis and of elastic fibers in the vein wall, proliferation of keratinocyte stem cells, and expression of the endothelial functional markers eNOS and FGF-2. These findings validate the suitability of this new ex vivo organ culture system for wound healing studies, not only for the scheduled space experiment but also for applications on Earth, such as drug discovery purposes.

Blue-LED-Light Photobiomodulation of Inflammatory Responses and New Tissue Formation in Mouse-Skin Wounds

Background: Recent studies evidence that blue-LED-light irradiation can modulate cell responses in the wound healing process within 24 h from treatment. This study aims to investigate blue-light (410-430 nm) photobiomodulation used in a murine wound model within six days post-treatment. Methods: A superficial wound was made in 30 CD1 male mice. The injuries were treated with a blue LED light (20.6 J/cm²), and biopsies were collected at 24, 72, and 144 h. Histology, fluorescence analysis, and advanced microscopy techniques were used. Results: We can observe an increase in the cellular infiltrate response, and in mast-cell density and their degranulation index correlated to the expression of the major histocompatibility complex after 24 h. Furthermore, after six days, the vessel density increases with the expression of the platelet-derived growth factor in the mast cells. Finally, collagen deposition and morphology in the treated wounds appear more similar to unwounded skin. Conclusions: Blue-light photobiomodulation stimulates several cellular processes that are finely coordinated by mast cells, leading to more rapid wound healing and a better-recovered skin morphology.

Analysis of Scars and Keloids by Focused Ion Beam/Scanning Electron Microscopy: Distinguishing Between Hypertrophic Scars and Keloids

BACKGROUND

Histological differentiation between hypertrophic scars (HSs) and keloids has been considered difficult. In this study, we analyzed differences in the 3-dimensional tissue architecture between HSs and keloids using focused ion beam/scanning electron microscopy (FIB/SEM).

METHODS

Five specimens each of normal skin, normotrophic scars (NSs), HSs, and keloids were investigated. Three sites in each specimen were observed by FIB/SEM tomography, resulting in an observation of 15 sites per tissue type. We identified fibroblasts and macrophages and assessed the contact ratio and the mode of intercellular contact (planar contact or point contact). The significance of differences among the 4 tissue types was determined by Fisher exact test.

RESULTS

In normal skin, contact between fibroblasts and macrophages was observed at all 15 sites, and the mode of contact was always planar. There was contact at 87% of the NS sites (planar: point = 80%: 7%). In HSs, contact was seen at 80% of the sites (planar: point = 20%: 60%). In keloids, contact was found at only 15% of the sites (planar: point = 7.5%: 7.5%). The intercellular contact ratio showed no significant differences among normal skin, NSs, and HSs; however, a significant difference was noted between these tissues and keloids. The intercellular contact mode also showed no significant difference between normal skin and NSs, but a significant difference between these tissues and HSs.

CONCLUSIONS

These histopathologic findings suggest that FIB/SEM tomography is useful for distinguishing between HSs and keloids and can provide important knowledge for understanding the pathogenesis of keloids.

Differences in the response in the dermis of the tails of young and old SD rats to treatment with bipolar RF

BACKGROUND

The passing of the years is marked by intrinsic (chronological) and extrinsic aging, caused by photoaging, which is characterized by a decrease in collagen and the deposition of abnormal elastic fibers in the dermis. The use of bipolar radiofrequency (RF) increases fibroblast proliferation and differentiation, accompanied by collagen synthesis and a subsequent increase in connective tissue, and it is not known whether the biological effects of this type of radiofrequency on the dermis are similar regardless of the age of the individual or whether such effects are altered by the aging process itself.

AIMS

The objective was to perform a histological study of the changes in the tail dermis of young and old rats after submitting them to bipolar RF, to determine cell proliferation and volume of connective tissue.

METHODS

One part of the rat tail was fixed in formol and processed for light microscopy and another part processed for electron microscopy.

RESULTS

The number of fibroblasts/unit area and cells positive to nuclear proliferation antigen was higher in young animals. Significant differences were observed regarding expression of HSP-47 protein, and the value was always lower in old rats. No significant differences were observed in the percentage of connective tissue. No histological alterations were observed in any rats.

CONCLUSION

Treatment with RF increased the number of fibroblasts located in the connective tissue of the young rats. In addition, the effect of a single treatment on the population of fibroblasts in young animals was sufficient to activate the synthesis of new collagen.

Angiotensin-Converting Enzyme Inhibitor, Captopril, Improves Scar Healing in Hypertensive Rats

Pathological cutaneous scars, with aberrant extracellular matrix accumulation, have multiple origins. Antihypertensive medications, such as calcium channel blockers, have been used to treat pathological scars. However, a relationship between angiotensin-converting enzyme (ACE) inhibitors, pathological scars, and blood pressure (BP) has never been reported. Here, we aimed to compare the differences in scar development and the effects of the administration of systemic ACE inhibitor on scar tissue in a normotensive rat, the Wistar Kyoto rat (WKY), a hypertensive rat, and the spontaneously hypertensive rat (SHR). Using an 8-mm punch, we created two full-thickness skin defects in a total of 32 rats (16 WKY and 16 SHR) to obtain a total of 64 wounds. We established control WKY (n = 16), captopril-treated WKY (n = 16), control SHR (n = 16), and captopril-treated SHR (n = 16) groups and started captopril (100 mg/g per day) treatment on day 21 in the appropriate groups. The BP of all groups was measured at 0, 3, and 5 weeks. The scar area was measured by histopathological examination, and scarring was expressed in terms of scar area and fibroblast and capillary counts. The expression of heat shock protein (HSP) 47, type I and III collagens, alpha-smooth muscle actin (α-SMA), Ki67, and vascular endothelial growth factor (VEGF) was investigated using immunohistochemistry. The scar area and fibroblast count were significantly higher in control SHR than in control WKY. The scar area, fibroblast count, and capillary count were significantly smaller in captopril-treated SHR than in control SHR. Immunostaining for α-SMA, Ki67, and VEGF also showed a noticeable decrease in scarring in the treated SHR compared with that in control SHR. Thus, BP affects scar development in a rat model, and an ACE inhibitor is more effective at reducing scars in hypertensive rats than in normotensive rats.

CD26 Identifies a Subpopulation of Fibroblasts that Produce the Majority of Collagen during Wound Healing in Human Skin

Fibroblasts produce collagens and other proteins that form the bulk of the extracellular matrix (ECM) in connective tissues. Emerging data point to functional heterogeneity of fibroblasts. However, the lack of subtype-specific markers hinders our understanding of the different roles of fibroblasts in ECM biology, wound healing, diseases, and aging. We have investigated the utility of the cell surface protein CD26 to identify functionally distinct fibroblast subpopulations in human skin. Using flow cytometry and immunohistology, we found that CD26, in combination with the cell surface glycoprotein CD90, identifies a distinct subpopulation of cells, which express relatively high levels of COL1A1, a hallmark of fibroblasts. Importantly, the population of CD26+ fibroblasts is selectively increased after wounding of human skin. These cells account for the majority of COL1A1 expression during the ECM remodeling phase of healing. The proportion of CD26+ fibroblasts in the skin of young and aged individuals is similar, indicating that the loss of collagen production during aging does not involve selective reduction of CD26+ fibroblasts. In culture, the majority of freshly isolated CD26- fibroblasts gain expression of CD26+. Taken together, these data provide a foundation for targeting CD26+ fibroblasts to modulate wound healing in human skin.

Rapid Fibroblast Cell Culture Characterization with Impedimetric Label‐free Heat Shock Protein – 47 Biosensor

In this study, for the first time in literature, an impedimetric biosensor technology was developed to determine Heat Shock Protein‐47 (HSP‐47) for the characterization of primary skin fibroblast cells. Gold nanoparticle electrodes (GNPE) were modified with amino‐functionalized graphene oxide layers and anti‐HSP‐47 were immobilized on this layer. The performance of the biosensor was tested with real samples as cell lysates. The low detection limit (LOD) and the linear detection limit (LOQ) of the biosensor were calculated as 9.47 pg/mL and 3.23 pg/mL, respectively. Linear measurement range was obtained between 10–160 pg/mL HSP‐47. The reproducibility of the biosensor was good.

Potential role of transforming growth factor-beta 1/Smad signaling in secondary lymphedema after cancer surgery

Secondary lymphedema often develops after cancer surgery, and over 250 million patients suffer from this complication. A major symptom of secondary lymphedema is swelling with fibrosis, which lowers the patient's quality of life, even if cancer does not recur. Nonetheless, the pathophysiology of secondary lymphedema remains unclear, with therapeutic approaches limited to physical or surgical therapy. There is no effective pharmacological therapy for secondary lymphedema. Notably, the lack of animal models that accurately mimic human secondary lymphedema has hindered pathophysiological investigations of the disease. Here, we developed a novel rat hindlimb model of secondary lymphedema and showed that our rat model mimics human secondary lymphedema from early to late stages in terms of cell proliferation, lymphatic fluid accumulation, and skin fibrosis. Using our animal model, we investigated the disease progression and found that transforming growth factor‐beta 1 (TGFB1) was produced by macrophages in the acute phase and by fibroblasts in the chronic phase of the disease. TGFB1 promoted the transition of fibroblasts into myofibroblasts and accelerated collagen synthesis, resulting in fibrosis, which further indicates that myofibroblasts and TGFB1/Smad signaling play key roles in fibrotic diseases. Furthermore, the presence of myofibroblasts in skin samples from lymphedema patients after cancer surgery emphasizes the role of these cells in promoting fibrosis. Suppression of myofibroblast‐dependent TGFB1 production may therefore represent an effective pharmacological treatment for inhibiting skin fibrosis in human secondary lymphedema after cancer surgery.

The biology of cutaneous neurofibromas: Consensus recommendations for setting research priorities

OBJECTIVE

A group of experts in dermatology, genetics, neuroscience, and regenerative medicine collaborated to summarize current knowledge on the defined factors contributing to cutaneous neurofibroma (cNF) development and to provide consensus recommendations for future research priorities to gain an improved understanding of the biology of cNF.

METHODS

The group members reviewed published and unpublished data on cNF and related diseases via literature search, defined a set of key topic areas deemed critical in cNF pathogenesis, and developed recommendations in a series of consensus meetings.

RESULTS

Five specific topic areas were identified as being relevant to providing an enhanced understanding of the biology of cNF: (1) defining the human cells of origin; (2) understanding the role of the microenvironment, focusing on neurons, mast cells, and fibroblasts; (3) defining the genetic and molecular differences between the cNFs, focusing on size and number; (4) understanding if sex hormones are critical for cNF development or progression; and (5) identifying challenges in establishing in vitro and in vivo models representing human cNF.

CONCLUSIONS

The complexity of cNF biology stems from its heterogeneity at multiple levels including genetic, spatial involvement, temporal development, and cellular composition. We propose a unified working model for cNF that builds a framework to address the key questions about cNF that, when answered, will provide the necessary understanding of cNF biology to allow meaningful development of therapies.

Evaluation of dermal wound healing activity of synthetic peptide SVVYGLR

SVVYGLR peptide (SV peptide) is a 7-amino-acid sequence with angiogenic properties that is derived from osteopontin in the extracellular matrix and promotes differentiation of fibroblasts to myofibroblast-like cells and the production of collagen type Ⅲ by cardiac fibroblasts. However, the effects of SV peptide on dermal cells and tissue are unknown. In this study, we evaluated the effects of this peptide in a rat model of dermal wound healing. The synthetic SV peptide was added to dermal fibroblasts or keratinocytes, and their cellular motility was evaluated. In an in vivo wound healing exeriment, male rats aged 8 weeks were randomly assigned to the SV peptide treatment, non-treated control, or phosphate-buffered saline (PBS) groups. Wound healing was assessed by its repair rate and histological features. Scratch assay and cell migration assays using the Chemotaxicell method showed that SV peptide significantly promoted the cell migration in both fibroblasts and keratinocytes. In contrast the proliferation potency of these cells was not affected by SV peptide. In the rat model, wound healing progressed faster in the SV peptide-treated group than in the control and PBS groups. The histopathological analyses showed that the SV peptide treatment stimulated the migration of fibroblasts to the wound area and increased the number of myofibroblasts. Immunohistochemical staining showed a marked increase of von Willebland factor-positive neomicrovessels in the SV peptide-treated group. In conclusion, SV peptide has a beneficial function to promote wound healing by stimulating granulation via stimulating angiogenesis, cell migration, and the myofibroblastic differentiation of fibroblasts.

Induction of mesenchymal stem cell differentiation in the absence of soluble inducer for cutaneous wound regeneration by a chitin nanofiber-based hydrogel

Transplantation of bone marrow mesenchymal stem cells (BMSCs) has been considered to be a promising strategy for wound healing. However, poor viability of engrafted BMSCs and limited capabilities of differentiation into the desired cell types in wounds often hinder its application. Few studies report the induction of BMSC differentiation into the skin regeneration-related cell types using natural biopolymer, e.g. chitin and its derivative. Here we utilized a chitin nanofiber (CNF) hydrogel as a directive cue to induce BMSC differentiation for enhancing cutaneous wound regeneration in the absence of cell-differentiating factors. First, a 'green' fabrication of CNF hydrogels encapsulating green fluorescence protein (GFP)-transfected rat BMSCs was performed via in-situ physical gelation without chemical cross-linking. Without soluble differentiation inducers, CNF hydrogels decreased the expression of BMSC transcription factors (Oct4 and Klf4) and concomitantly induced their differentiation into the angiogenic cells and fibroblasts, which are indispensable for wound regeneration. In vivo, rat full-thickness cutaneous wounds treated with BMSC hydrogel exhibited better viability of the cells than did local BMSC injection-treated wounds. Similar to that of the in vitro result, CNF hydrogels induced BMSCs to differentiate into beneficial cell types, resulting in accelerated wound repair characterized by granulation tissue formation. Our data suggest that three-dimensional CNF hydrogel may not only serve as a 'protection' to improve the viability of exogenous BMSCs, but also provide a functional scaffold capable of enhancing BMSC regenerative potential to promote wound healing. This may help to overcome the current limitations to stem cell therapy that are faced in the field of wound regeneration. Copyright © 2017 John Wiley & Sons, Ltd.

Detection of RAGE expression and its application to diabetic wound age estimation

With the prevalence of diabetes, it is becoming important to analyze the diabetic wound age in forensic practice. The present study investigated the time-dependent expression of receptor for advanced glycation end products (RAGE) during diabetic wound healing in mice and its applicability to wound age determination by immunohistochemistry, double immunofluorescence, and Western blotting. After an incision was created in genetically diabetic db/db mice and control mice, mice were killed at posttraumatic intervals ranging from 6 h to 14 days, followed by the sampling of wound margin. Compared with control mice, diabetic mice showed the delayed wound healing. In control and diabetic wound specimens, RAGE immunoreactivity was observed in a small number of polymorphonuclear cells (PMNs), a number of macrophages, and fibroblasts. Morphometrically, the positive ratios of RAGE in macrophages or fibroblasts considerably increased in diabetic wounds during late repair, which exceeded 60% at 7 and 10 days post-injury. There were no control wound specimens to show a ratio of >60% in macrophages or fibroblasts. By Western blotting analysis, the ratios of RAGE to GAPDH were >1.4 in all diabetic wound samples from 7 to 10 days post-injury, which were >1.8 at 10 days after injury. By comparison, no control wound specimens indicated a ratio of >1.4. In conclusion, the expression of RAGE is upregulated and temporally distributed in macrophages and fibroblasts during diabetic wound healing, which might be closely involved in prolonged inflammation and deficient healing. Moreover, RAGE is promising as a useful marker for diabetic wound age determination.

Noggin inactivation affects the number and differentiation potential of muscle progenitor cells in vivo

Inactivation of Noggin, a secreted antagonist of Bone Morphogenetic Proteins (BMPs), in mice leads, among others, to severe malformations of the appendicular skeleton and defective skeletal muscle fibers. To determine the molecular basis of the phenotype, we carried out a histomorphological and molecular analysis of developing muscles Noggin(-/-) mice. We show that in 18.5 dpc embryos there is a marked reduction in muscle fiber size and a failure of nuclei migration towards the cell membrane. Molecularly, the absence of Noggin results in an increased BMP signaling in muscle tissue as shown by the increase in SMAD1/5/8 phosphorylation, concomitant with the induction of BMP target genes such as Id1, 2, 3 as well as Msx1. Finally, upon removal of Noggin, the number of mesenchymal Pax7(+) muscle precursor cells is reduced and they are more prone to differentiate into adipocytes in vitro. Thus, our results highlight the importance of Noggin/BMP balance for myogenic commitment of early fetal progenitor cells.

Interaction between Macrophages and Fibroblasts during Wound Healing of Burn Injuries in Rats

Analysis of the structural changes and cell-to-cell interactions occurring during wound healing of burn injuries is essential to elucidate the morphological characteristics of the reconstitution of tissue architecture. However, conventional approaches do not provide sufficient information with respect to cell-to-cell interactions during wound healing. The aim of this study was to evaluate the interaction between bone marrow-derived cells and resident stromal cells throughout the wound healing of burn injuries, using immunohistochemistry and focused ion beam/scanning electron microscope tomography. We induced third-degree burn injuries on the backs of Wistar rats with a heated cylindrical aluminum block (2.0 cm in diameter). At 7 and 14 days after the burn injuries, the burned skin was immunostained with anti-Iba1 and anti-HSP47 antibodies for visualization of bone marrow-derived cells/macrophages and resident stromal cells/fibroblasts, respectively. Normal skin tissue was used as a control. Double-staining immunohistochemistry revealed frequent contacts between macrophages and fibroblasts and a higher contact ratio in the 3 normal skin compared with burned skin, particularly in the areas of granuloma. Three-dimensional ultrastructural analysis with focused ion beam/scanning electron microscope tomography revealed that macrophages and fibroblasts were located closer together in the normal skin than in the burned skin, confirming the analysis by light microscopic observations and ultrastructural analysis from single sections. These results highlight the importance of contact between macrophages and fibroblasts in the maintenance of skin tissue structure and during wound healing.

MHC-compatible bone marrow stromal/stem cells trigger fibrosis by activating host T cells in a scleroderma mouse model

Fibrosis of organs is observed in systemic autoimmune disease. Using a scleroderma mouse, we show that transplantation of MHC compatible, minor antigen mismatched bone marrow stromal/stem cells (BMSCs) play a role in the pathogenesis of fibrosis. Removal of donor BMSCs rescued mice from disease. Freshly isolated PDGFRα⁺ Sca-1⁺ BMSCs expressed MHC class II following transplantation and activated host T cells. A decrease in FOXP3⁺ CD25⁺ Treg population was observed. T cells proliferated and secreted IL-6 when stimulated with mismatched BMSCs in vitro. Donor T cells were not involved in fibrosis because transplanting T cell-deficient RAG2 knock out mice bone marrow still caused disease. Once initially triggered by mismatched BMSCs, the autoimmune phenotype was not donor BMSC dependent as the phenotype was observed after effector T cells were adoptively transferred into naïve syngeneic mice. Our data suggest that minor antigen mismatched BMSCs trigger systemic fibrosis in this autoimmune scleroderma model.

DOI:http://dx.doi.org/10.7554/eLife.09394.001

Systemic scleroderma is an autoimmune disease caused by the immune system attacking the body’s connective tissues, which provide the body with structural support. Immune cells called T cells accumulate in connective tissue, which leads to the hardening of the skin and may also damage the heart, lungs and other internal organs. However, it is not clear what prompts the T cells to accumulate in the connective tissues of these individuals.

Autoimmune diseases develop when the immune system mistakenly identifies host cells as being a threat to the body. Normally, the immune system recognizes healthy body cells by the presence of particular proteins on the surface of the cells. A set of surface proteins called the major histocompatibility complexes (MHCs) play a major role in this process, but there are also many other surface proteins that play more minor roles.

In 2002, researchers developed a method that can trigger the symptoms of systemic scleroderma in mice. This method involves transplanting bone marrow from one mouse into another mouse. Both mice have identical MHC proteins on the surfaces of their cells, but have some differences in other cell surface proteins, and so the bone marrow from the donor mouse triggers an immune response in the recipient.

To better understand how this mouse “model” of systemic scleroderma works, Ogawa, Morikawa et al. refined the method so that they could just transplant specific types of bone marrow cells into the recipient mice. The experiments reveal that bone marrow stromal stem cells, but not so-called “hematopoietic stem cells”, from a donor mouse are responsible for triggering the immune response and disease symptoms in the recipients.

Ogawa, Morikawa et al.’s findings show that mismatched minor cell surface proteins on bone marrow stromal stem cells can trigger symptoms of systemic scleroderma in mice. Further studies are required to find out how these cells encourage T cells to trigger an autoimmune response.

DOI:http://dx.doi.org/10.7554/eLife.09394.002

Preformed gelatin microcryogels as injectable cell carriers for enhanced skin wound healing

Wound dressings of cell-laden bulk hydrogel or scaffold were mainly applied for enhanced cell engraftment in contrast to free cell injection. However, dressing of cells laden in biomaterials on wound surface might not effectively and timely exert functions on deep or chronic wounds where insufficient blood supply exists. Previously, we developed injectable gelatin microcryogels (GMs) which could load cells for enhanced cell delivery and cell therapy. In this study, biological changes of human adipose-derived stem cells (hASCs) laden in GMs were compared in varied aspects with traditional two dimensional (2D) cell culture, such as cell phenotype markers, stemness genes, differentiation, secretion of growth factors, cell apoptosis and cell memory by FACS, QRT-PCR and ELISA, that demonstrated the priming effects of GMs on upregulation of stemness genes and improved secretion of growth factors of hASCs for potential augmented wound healing. In a full-thickness skin wound model in nude mice, multisite injection and dressing of hASCs-laden GMs could significantly accelerate the healing compared to free cell injection. Bioluminescence imaging and protein analysis indicated improved cell retention and secretion of multiple growth factors. Our study suggests that GMs as primed injectable 3D micro-niches represent a new cell delivery methodology for skin wound healing which could not only benefit on the recovery of wound bed but also play direct effects on wound basal layer for healing enhancement. Injectable GMs as facile multisite cell delivery approach potentially provide new minimally-invasive therapeutic strategy for refractory wounds such as diabetic ulcer or radiative skin wound.

STATEMENT OF SIGNIFICANCE

This work applied a type of elastic micro-scaffold (GMs) to load and prime hMSCs for skin wound healing. Due to the injectability of GMs, the 3D cellular micro-niches could simply realize minimally-invasive and multisite cell delivery approach for accelerating the wound healing process superior to free cell injection. The biological features of MSCs has been thoroughly characterized during 3D culture in GMs (i.e. cell proliferation, characterization of cell surface markers, stemness of MSCs in GMs, differentiation of MSCs in GMs, secretion of MSCs in GMs, induced apoptosis of MSCs in GMs). Multiple methods such as bioluminescent imaging, immunohistochemistry, immunofluorescence, qRT-PCR, ELSA and western blot were used to assess the in vivo results between groups.

Up-regulation of Hsp72 and keratin16 mediates wound healing in streptozotocin diabetic rats

Background

Impaired wound healing is a complication of diabetes and a serious problem in clinical practice. We previously found that whey protein (WP) was able to regulate wound healing normally in streptozotocin (STZ)-diabetic models. This subsequent study was designed to assess the effect of WP on heat shock protein-72 (Hsp72) and keratin16 (Krt16) expression during wound healing in diabetic rats.

Methods

WP at a dosage of 100 mg/kg of body weight was orally administered daily to wounded normal and STZ-diabetic rats for 8 days.

Results

At day 4, the WP-treated diabetic wound was significantly reduced compared to that in the corresponding control. Diabetic wounded rats developed severe inflammatory infiltration and moderate capillary dilatation and regeneration. Treated rats had mild necrotic formation, moderate infiltration, moderate to severe capillary dilatation and regeneration, in addition to moderate epidermal formation. Hsp72 and Krt16 densities showed low and dense activity in diabetic wounded and diabetic wounded treated groups, respectively. At day 8, WP-treatment of diabetic wounded animals revealed great amelioration with complete recovery and closure of the wound. Reactivity of Hsp72 and Krt16 was reversed, showing dense and low, or medium and low, activity in the diabetic wounded and diabetic wounded treated groups, respectively. Hsp72 expression in the pancreas was found to show dense reactivity with WP-treated diabetic wound rats.

Conclusion

This data provides evidence for the potential impact of WP in the up-regulation of Hsp72 and Krt16 in T1D, resulting in an improved wound healing process in diabetic models.

Concise Review: Human Dermis as an Autologous Source of Stem Cells for Tissue Engineering and Regenerative Medicine

The exciting potential for regenerating organs from autologous stem cells is on the near horizon, and adult dermis stem cells (DSCs) are particularly appealing because of the ease and relative minimal invasiveness of skin collection. A substantial number of reports have described DSCs and their potential for regenerating tissues from mesenchymal, ectodermal, and endodermal lineages; however, the exact niches of these stem cells in various skin types and their antigenic surface makeup are not yet clearly defined. The multilineage potential of DSCs appears to be similar, despite great variability in isolation and in vitro propagation methods. Despite this great potential, only limited amounts of tissues and clinical applications for organ regeneration have been developed from DSCs. This review summarizes the literature on DSCs regarding their niches and the specific markers they express. The concept of the niches and the differentiation capacity of cells residing in them along particular lineages is discussed. Furthermore, the advantages and disadvantages of widely used methods to demonstrate lineage differentiation are considered. In addition, safety considerations and the most recent advancements in the field of tissue engineering and regeneration using DSCs are discussed. This review concludes with thoughts on how to prospectively approach engineering of tissues and organ regeneration using DSCs. Our expectation is that implementation of the major points highlighted in this review will lead to major advancements in the fields of regenerative medicine and tissue engineering.

SIGNIFICANCE

Autologous dermis-derived stem cells are generating great excitement and efforts in the field of regenerative medicine and tissue engineering. The substantial impact of this review lies in its critical coverage of the available literature and in providing insight regarding niches, characteristics, and isolation methods of stem cells derived from the human dermis. Furthermore, it provides analysis of the current state-of-the-art regenerative approaches using human-derived dermal stem cells, with consideration of current guidelines, to assist translation toward therapeutic use.

Epidermal Expression and Regulation of Interleukin-33 during Homeostasis and Inflammation: Strong Species Differences

IL-33 is a novel IL-1 family member with a putative role in inflammatory skin disorders and a complex biology. Therefore, recent conflicting data regarding its function in experimental models justify a close assessment of its tissue expression and regulation. Indeed, we report here that there are strong species differences in the expression and regulation of epidermal IL-33. In murine epidermis, IL-33 behaved similar to an alarmin, being constitutively expressed in keratinocyte nuclei and rapidly lost during acute inflammation. By contrast, human and porcine IL-33 were weakly expressed or absent in keratinocytes of noninflamed skin but induced during acute inflammation. To this end, we observed that expression of IL-33 in human keratinocytes but not murine keratinocytes was strongly induced by IFN-γ, and this upregulation completely depended on the presence of EGFR ligands. Accordingly, IFN-γ increased the expression of IL-33 in the basal layers of the epidermis in human ex vivo skin cultures only, despite good evidence of IFN-γ activity in cultures from both species. Together these findings demonstrate that a full understanding of IL-33 function in clinical settings must take species-specific differences into account.

MUC1 Is Expressed by Human Skin Fibroblasts and Plays a Role in Cell Adhesion and Migration

The mucin MUC1 is expressed by normal and cancerous epithelial cells and some nonepithelial cells in which it plays roles in regulating adhesion, migration, and cell signaling. In the present studies we found that MUC1 is expressed by normal human neonatal and adult skin fibroblasts. Fibroblasts are usually considered negative for MUC1 expression. Reverse-transcription polymerase chain reaction and Western blot analyses indicate the presence of full-length MUC1, and immunofluorescence and subcellular fractionation studies show that the protein is expressed on the plasma membrane. Immunohistochemical analyses confirmed the expression of MUC1 by fibroblasts in cryosections of normal human skin. Silencing MUC1 expression in fibroblasts using MUC1 shRNA increased the adhesion of cells to collagen and laminin. Transfection with MUC1 shRNA also increased fibroblast migration on collagen as measured in a wound-healing assay. The expression of α₂-integrin was increased in MUC1 shRNA-transfected fibroblasts in which it was localized to membrane ruffles, providing a possible explanation for the increased cell migration on collagen. These results extend the range of expression of MUC1 to skin fibroblasts and suggest a functional role for MUC1 in fibroblast adhesion and motility.

Peripheral blood fibrocytes: new information to explain the dynamics of Leishmania infection

Fibrocytes are important for understanding the progression of many diseases because they are present in areas where pathogenic lesions are generated. However, the morphology of fibrocytes and their interactions with parasites are poorly understood. In this study, we examined the morphology of peripheral blood fibrocytes and their interactions with Leishmania (L.) amazonensis . Through ultrastructural analysis, we describe the details of fibrocyte morphology and how fibrocytes rapidly internalise Leishmania promastigotes. The parasites differentiated into amastigotes after 2 h in phagolysosomes and the infection was completely resolved after 72 h. Early in the infection, we found increased nitric oxide production and large lysosomes with electron-dense material. These factors may regulate the proliferation and death of the parasites. Because fibrocytes are present at the infection site and are directly involved in developing cutaneous leishmaniasis, they are targets for effective, non-toxic cell-based therapies that control and treat leishmaniasis.

Skin punch biopsy explant culture for derivation of primary human fibroblasts

Tissues and cell lines derived from an individual with disease are ideal sources to study disease-related cellular phenotypes. Patient-derived fibroblasts in this protocol have been successfully used in the derivation of induced pluripotent stem cells to model disease(1). Early passages of these fibroblasts can also be used for cell-based functional assays to study specific disease pathways, mechanisms(2) and subsequent drug screening approaches. The advantage of the presented protocol over enzymatic procedures are 1) the reproducibility of the technique from small amounts of tissue derived from older patients, e.g. patients affected with Parkinson's disease, 2) the technically simple approach over more challenging methodologies using enzymatic treatments, and 3) the time consideration: this protocol takes 15-20 min and can be performed immediately after biopsy arrival. Enzymatic treatments can take up to 4 hr and have the problems of overdigestion, reduction of cell viability and subsequent attachment of cells when not handled properly. This protocol describes the dissection and preparation of a 4-mm human skin biopsy for derivation of a fibroblast culture and has a very high success rate which is important when dealing with patient-derived tissue samples. In this culture, keratinocytes migrate out of the biopsy tissue within the first week after preparation. Fibroblasts appear 7-10 days after the first outgrowth of keratinocytes. DMEM high glucose media supplemented with 20% FBS favors the growth of fibroblasts over keratinocytes and fibroblasts will overgrow the keratinocytes. After 2 passages keratinocytes have been diluted out resulting in relatively homogenous fibroblast cultures which expresses the fibroblast marker SERPINH1 (HSP-47). Using this approach, 15-20 million fibroblasts can be derived in 4-8 weeks for cell banking. The skin dissection takes about 15-20 min, cells are then monitored once a day under the microscope, and media is changed every 2-3 days after attachment and outgrowth of cells.

Synovial fibroblast hyperplasia in rheumatoid arthritis: clinicopathologic correlations and partial reversal by anti-tumor necrosis factor therapy

OBJECTIVE

Synovial fibroblast (SF) hyperplasia contributes to the pathogenesis of rheumatoid arthritis (RA), but quantitative information on this process is scarce. This study was undertaken to evaluate the fibroblast-specific marker Hsp47 as a quantitative marker for SFs and to analyze its clinicopathologic correlates and evolution after anti-tumor necrosis factor α (anti-TNFα) therapy.

METHODS

Synovial biopsy samples were obtained from 48 patients with RA and 20 controls who were healthy or had osteoarthritis (OA). Twenty-five RA patients who had active disease at the time of biopsy underwent a second biopsy after anti-TNFα therapy. Immunolabeling for Hsp47, inflammatory cells, and vascular cell markers was performed. Hsp47-positive lining and sublining fractional areas were quantified, and their correlation with clinicopathologic variables was analyzed.

RESULTS

In normal and diseased synovial tissue, Hsp47 was specifically and uniformly expressed by lining, sublining, and perivascular fibroblasts. Lining SF area was significantly increased in both RA and late OA tissue compared to normal tissue. Sublining SF area was increased in RA tissue but not in late OA tissue compared to normal tissue. Lining SF area was positively correlated with macrophage density, Disease Activity Score in 28 joints, and RA disease duration. In contrast, sublining SF area was negatively correlated with RA disease duration and activity. A significant reduction in lining SF area but not sublining SF area was observed after anti-TNFα therapy.

CONCLUSION

Our findings indicate that Hsp47 is a reliable marker for quantifying SFs in human synovial tissue. Our data suggest that lining and sublining SFs undergo different dynamics during the course of the disease. Lining SF expansion parallels the activity and temporal progression of RA and can be partially reversed by anti-TNFα therapy.

Enhancement of mesenchymal stem cell angiogenic capacity and stemness by a biomimetic hydrogel scaffold

In this study, we examined the capacity of a biomimetic pullulan-collagen hydrogel to create a functional biomaterial-based stem cell niche for the delivery of mesenchymal stem cells (MSCs) into wounds. Murine bone marrow-derived MSCs were seeded into hydrogels and compared to MSCs grown in standard culture conditions. Hydrogels induced MSC secretion of angiogenic cytokines and expression of transcription factors associated with maintenance of pluripotency and self-renewal (Oct4, Sox2, Klf4) when compared to MSCs grown in standard conditions. An excisonal wound healing model was used to compare the ability of MSC-hydrogel constructs versus MSC injection alone to accelerate wound healing. Injection of MSCs did not significantly improve time to wound closure. In contrast, wounds treated with MSC-seeded hydrogels showed significantly accelerated healing and a return of skin appendages. Bioluminescence imaging and FACS analysis of luciferase+/GFP+ MSCs indicated that stem cells delivered within the hydrogel remained viable longer and demonstrated enhanced engraftment efficiency than those delivered via injection. Engrafted MSCs were found to differentiate into fibroblasts, pericytes and endothelial cells but did not contribute to the epidermis. Wounds treated with MSC-seeded hydrogels demonstrated significantly enhanced angiogenesis, which was associated with increased levels of VEGF and other angiogenic cytokines within the wounds. Our data suggest that biomimetic hydrogels provide a functional niche capable of augmenting MSC regenerative potential and enhancing wound healing.

The recruitment of bone marrow-derived cells to skin wounds is independent of wound size

Wounded skin recruits progenitor cells, which repair the tissue defect. These cells are derived from stem cells in several niches in the skin. In addition, bone marrow-derived cells (BMDCs) are recruited and contribute to wound repair. We hypothesized that larger wounds recruit more cells from the bone marrow. Wild-type rats were lethally irradiated and transplanted with bone marrow cells from green fluorescent protein (GFP)-transgenic rats. Seven weeks later, 4, 10, and 20 mm wounds were created. The wound tissue was harvested after 14 days. The density of GFP-positive cells in the wounds and the adjacent tissues was determined, as well as in normal skin from the flank. Bone marrow-derived myofibroblasts, activated fibroblasts, and macrophages were also quantified. After correction for cell density, the recruitment of BMDCs (23±11%) was found to be independent of wound size. Similar fractions of GFP-positive cells were also detected in nonwounded adjacent tissue (29±11%), and in normal skin (26±19%). The data indicate that BMDCs are not preferentially recruited to skin wounds. Furthermore, wound size does not seem to affect the recruitment of BMDCs.

The basement membrane of hair follicle stem cells is a muscle cell niche

The hair follicle bulge in the epidermis associates with the arrector pili muscle (APM) that is responsible for piloerection ("goosebumps"). We show that stem cells in the bulge deposit nephronectin into the underlying basement membrane, thus regulating the adhesion of mesenchymal cells expressing the nephronectin receptor, α8β1 integrin, to the bulge. Nephronectin induces α8 integrin-positive mesenchymal cells to upregulate smooth muscle markers. In nephronectin knockout mice, fewer arrector pili muscles form in the skin, and they attach to the follicle above the bulge, where there is compensatory upregulation of the nephronectin family member EGFL6. Deletion of α8 integrin also abolishes selective APM anchorage to the bulge. Nephronectin is a Wnt target; epidermal β-catenin activation upregulates epidermal nephronectin and dermal α8 integrin expression. Thus, bulge stem cells, via nephronectin expression, create a smooth muscle cell niche and act as tendon cells for the APM. Our results reveal a functional role for basement membrane heterogeneity in tissue patterning. PAPERCLIP:

Bone marrow-derived cells in palatal wound healing

OBJECTIVE

Myofibroblasts are responsible for contraction and scarring after cleft palate repair. This leads to growth disturbances in the upper jaw. We hypothesized that cells from the bone marrow are recruited to palatal wounds and differentiate into myofibroblasts.

METHODS

We transplanted bone marrow from green fluorescent protein (GFP)-transgenic rats into lethally irradiated wild-type rats. After recovery, experimental wounds were made in the palatal mucoperiosteum, and harvested 2 weeks later. GFP-expressing cells were identified using immunostaining. Myofibroblasts, activated fibroblasts, endothelial cells, and myeloid cells were quantified with specific markers.

RESULTS

After transplantation, 89 ± 8.9% of mononuclear cells in the blood expressed the GFP and about 50% of adherent cells in the bone marrow. Tissue obtained during initial wounding contained only minor numbers of GFP-positive cells, like adjacent control tissue. Following wound healing, 8.1 ± 5.1% of all cells in the wound area were positive, and 5.0 ± 4.0% of the myofibroblasts, which was significantly higher than in adjacent tissue. Similar percentages were found for activated fibroblasts and endothelial cells, but for myeloid cells it was considerably higher (22 ± 9%).

CONCLUSIONS

Bone marrow-derived cells contribute to palatal wound healing, but are not the main source of myofibroblasts. In small wounds, the local precursor cells are probably sufficient to replenish the defect.

Impaired wound healing in mouse models of diabetes is mediated by TNF-alpha dysregulation and associated with enhanced activation of forkhead box O1 (FOXO1)

AIMS/HYPOTHESIS

The role of TNF-alpha in impaired wound healing in diabetes was examined by focusing on fibroblasts.

METHODS

Small excisional wounds were created in the db/db mice model of type 2 diabetes and normoglycaemic littermates, and in a streptozotocin-induced type 1 diabetes mouse model and control mice. Fibroblast apoptosis was measured by the TUNEL assay, proliferation by detection of proliferating cell nuclear antigen, and forkhead box O1 (FOXO1) activity by DNA binding and nuclear translocation. TNF-alpha was specifically inhibited by pegsunercept.

RESULTS

Diabetic wounds had increased TNF-alpha, fibroblast apoptosis, caspase-3/7 activity and activation of the pro-apoptotic transcription factor FOXO1, and decreased proliferating cell nuclear antigen positive fibroblasts (p < 0.05). TNF-alpha inhibition improved healing in the diabetic mice and increased fibroblast density. This may be explained by a decrease in fibroblast apoptosis and increased proliferation when TNF-alpha was blocked (p < 0.05). Although decreased fibroblast proliferation and enhanced FOXO1 activity were investigated in type 2 diabetes, they may also be implicated in type 1 diabetes. In vitro, TNF-alpha enhanced mRNA levels of gene sets related to apoptosis and Akt and p53 but not mitochondrial or cell-cycle pathways. FOXO1 small interfering RNA reduced gene sets that regulate apoptosis, Akt, mitochondrial and cell-cycle pathways. TNF-alpha also increased genes involved in inflammation, cytokine, Toll-like receptor and nuclear factor-kB pathways, which were significantly reduced by FOXO1 knockdown.

CONCLUSIONS/INTERPRETATION

These studies indicate that TNF-alpha dysregulation in diabetic wounds impairs healing, which may involve enhanced fibroblast apoptosis and decreased proliferation. In vitro, TNF-alpha induced gene sets through FOXO1 that regulate a number of pathways that could influence inflammation and apoptosis.

Immunohistochemical investigation of wound healing in response to fractional photothermolysis

Despite growing clinical evidence of ablative fractional photothermolysis (AFP), little is known about the spatiotemporal molecular changes within the targeted compartments. Six subjects received three different single AFP treatments using a scanned 250 mum CO(2)-laser beam. Spatiotemporal changes of skin regeneration were estimated by immunohistochemical investigation (HSP70, HSP72, HSP47, TGFbeta, procollagen III, CD3, CD20, and CD68) in skin samples 1 h, 3 days, and 14 days postintervention. The remodeling was uniformly started by regrowth of the epidermal compartment followed by partial to complete replacement of the microscopic ablation zones (MAZ) by newly synthesized condensed procollagen III. From day 3 to 14, the number of macrophages as well as giant cells surrounding the MAZ increased. TGFbeta expression was highest 1 h to 3 days following AFP. HSP70 and HSP72 expressions were highest 3-14 days postintervention in the spinocellular layer leading to an upregulation of HSP47. AFP performed by a scanned CO(2)-laser results in an early epidermal remodeling, which is followed by a dermal remodeling leading to a replacement of the MAZ with newly synthesized (pro)-collagen. During this, an inflammatory infiltrate with CD3(+) and CD20(+) cells surrounds the MAZ. The count of macrophages and giant cells involved in the replacement of the necrotic zones seems to be crucial for wound healing.

Proliferation of HSP47-positive skin fibroblasts in dermatofibroma

BACKGROUND

The cell origin of dermatofibroma (DF) has not been clarified satisfactorily. This study was undertaken to assess the distribution of fibroblasts and the relationship between fibroblasts and other constituent cells in DF by 47-kDa heat-shock protein (HSP47), a cell marker for skin fibroblast.

METHODS

Immunohistochemistry was performed to evaluate the expression of HSP47 and other cell markers in histological variants of DF.

RESULTS

Almost all spindle-shaped cells showed strong immunoreactivity for HSP47 in DF. In the fibrocollagenous type, a common type of DF, HSP47-positive fibroblasts were the major constituent cells. In the cellular and atypical types, many constituent cells were positive for HSP47. Huge cells with bizarre nuclei, which are distinctive of the atypical type, showed immunoreactivity for HSP47, not for CD68 or factor XIIIa (FXIIIa). In the histiocytic and angiomatous types, CD68-positive histiocytes were the major constituent cells, but many scattered spindle cells were positive for HSP47. FXIIIa-positive dermal dendritic cells were increased, irrespective of DF variants, whereas the cell number varied from case to case.

CONCLUSIONS

Skin fibroblast is one of the major constituent cells in DF, and DF may be composed chiefly of two types of cell lineages, fibroblasts and bone marrow-derived monocyte/macrophages (dermal dendritic cells and/or histiocytes).

Dermal matrix as a carrier for in vivo delivery of human adipose-derived stem cells

The aim of the present study was to evaluate the potential of acellular dermal matrix as a carrier for delivery of stem cells to the site of soft tissue defect in a murine skin injury model and to determine the potential of stem cells delivered via such an approach to successfully engraft, survive and differentiate locally. We showed that adipose-derived stem cells delivered via this matrix survived after in vivo engraftment, spontaneously differentiated along vascular endothelial, fibroblastic and epidermal epithelial lineages and significantly improved wound healing. Furthermore, an organ survey for transplanted cells showed no evidence of a systemic distribution beyond the cutaneous wound site, indicating that the adipose-derived stem cell-dermal matrix construct provides a novel and effective method for anatomically focused cellular therapy. In conclusion, stem cell-seeded dermal matrix is an effective means for targeted in vivo cell delivery for enhanced soft tissue regeneration.

Nitric oxide in the pathogenesis of diffuse pulmonary fibrosis

By studying the responses of nitric oxide in pulmonary fibrosis, the role of inducible nitric oxide synthase in diffuse pulmonary fibrosis as caused by lipopolysaccharide (LPS) treatment was investigated. When compared to rats treated with LPS only, the rats pretreated with 1400W (an iNOS-specific inhibitor) were found to exhibit a reduced level in: (i) NOx (nitrate/nitrite) production, (ii) collagen type I protein expression, (iv) soluble collagen production, and (iv) the loss of body weight and carotid artery PO2. In the pulmonary fibroblast culture, exogenous NO from LPS-stimulated secretion by macrophages or from a NO donor, such as DETA NONOate, was observed to induce the expression of TIMP-1, HSP47, TGF-beta1, and collagen type I as well as the phosphorylation of SMAD-2. After inhalation of NO for 24 h, an up-regulation of collagen type I protein was also noted to occur in rat pulmonary tissue. The results suggest that the NO signal pathway enhanced the expression of TGF-beta1, TIMP-1, and HSP47 in pulmonary fibroblasts, which collectively demonstrate that the NO signal pathway could activate the SMAD-signal cascade, by initiating a rapid increase in TGF-beta1, thereby increasing the expression of TIMP-1 and HSP47 in pulmonary fibroblasts, and play an important role in pulmonary fibrosis.

Heat shock proteins 47 and 70 expression in rodent skin model as a function of contact cooling temperature: Are we overcooling our target?

BACKGROUND AND OBJECTIVES

The degree of protective cooling required during laser therapy to achieve an optimal result is unknown. The expression of heat shock proteins, Hsp47 and Hsp70, were examined in the epidermis and dermis as biomarkers to quantify the degree and depth of tissue affected by non-ablative laser treatment using variable protective cooling parameters.

STUDY DESIGN/MATERIALS AND METHODS

Twenty-one male Sprague-Dawley rats were treated with a 1,319 nm Nd:YAG laser using a sapphire cooling plate attached to the hand piece. A 4 cmx4 cm area on each side of the rat was treated with the same energy and pulse settings, with variable contact cooling. Protective cooling parameters, for each degree increment, ranging from 0 to 25 degrees C were studied. Immunohistochemistry (IHC), Western blot and PCR were performed to evaluate the effects of superficial cooling on Hsp47, and Hsp70 expressions.

RESULTS

Our data showed the extent of topical cooling needed to produce a thermal effect at different depths in the dermis, quantified by the expression of Hsp47 and Hsp70. Significant Hsp expression was observed with cooling of 13 degrees C and warmer; no identifiable cellular reaction was observed when cooling below 5 degrees C. There was no evidence of epidermal injury when treating the skin with any protective cooling ranging from 0 to 25 degrees C.

CONCLUSION

Our data would suggest contact cooling temperatures 5 degrees C and below completely protects through the entire dermis. There was no evidence of epidermal injury with protective cooling at any temperature between 0 and 25 degrees C. Warmer temperatures are safe and adequately protect the epidermis in this model.

Elevated cysteine-rich 61 mediates aberrant collagen homeostasis in chronologically aged and photoaged human skin

Alterations of human skin connective tissue structure and function are prominent features of chronological aging and solar UV irradiation-induced premature aging (photoaging). These skin connective tissue abnormalities result, in part, from reduced synthesis and elevated degradation of type I collagen, the major structural protein in skin. Here, we report that cysteine-rich 61 (CYR61/CCN1), a novel mediator of collagen homeostasis, is predominantly expressed in human skin connective tissue and is significantly elevated in fibroblasts in chronologically aged (80+ years) and photoaged human skin in vivo. In cultured human skin fibroblasts, elevated CYR61 expression substantially reduces type I procollagen and concurrently increases matrix metalloproteinase-1 (MMP-1), which initiates fibrillar collagen degradation. Elevated CYR61 caused down-regulation of transforming growth factor-beta type II receptor mRNA and protein levels, thereby impairing the transforming growth factor-beta pathway, which reduced type I procollagen and raised MMP-1 expression. Furthermore, elevated CYR61 induced transcription factor activator protein-1 (AP-1), which functions to stimulate MMP-1 expression. Thus, elevated expression of CYR61 in human skin fibroblasts acts through multiple pathways to cause alterations of collagen homeostasis similar to those pathways observed in aged human skin in vivo. These data identify CYR61 as a pivotal regulator of collagen production and degradation in aged and photoaged human skin.

Reversine-treated fibroblasts acquire myogenic competence in vitro and in regenerating skeletal muscle

Stem cells hold a great potential for the regeneration of damaged tissues in cardiovascular or musculoskeletal diseases. Unfortunately, problems such as limited availability, control of cell fate, and allograft rejection need to be addressed before therapeutic applications may become feasible. Generation of multipotent progenitors from adult differentiated cells could be a very attractive alternative to the limited in vitro self-renewal of several types of stem cells. In this direction, a recently synthesized unnatural purine, named reversine, has been proposed to induce reversion of adult cells to a multipotent state, which could be then converted into other cell types under appropriate stimuli. Our study suggests that reversine treatment transforms primary murine and human dermal fibroblasts into myogenic-competent cells both in vitro and in vivo. Moreover, this is the first study to demonstrate that plasticity changes arise in primary mouse and human cells following reversine exposure.

Generation and Differentiation of Human Embryonic Stem Cell-Derived Keratinocyte Precursors

Human embryonic stem cells (hESC) hold tremendous potential in the future of tissue engineering, offering promise as a source of virtually unlimited quantities of desired cell and tissue types. We have identified soluble chemical and extracellular matrix factors that permit isolation of keratinocyte precursors from hESCs. Culturing embryoid bodies (EB) formed from hESCs in a defined serum-free keratinocyte growth medium on a gelatin matrix generated keratin 14 (K14) expressing cells with an epithelial morphology. These K14 expressing cells could be subcultured in medium supplemented with hydrocortisone and induced to stratify and terminally differentiate by addition of calcium. Optimum times for obtaining K14 expressing cells were found for EB formation and for differentiation and growth of cultures after EB plating. EB formation was not necessary to generate keratinocyte precursors; direct transfer of hESC colonies to keratinocyte growth medium permitted differentiation into the keratinocyte lineage. With further studies to optimize generation and purification of hESC-derived keratinocyte precursors, these cells could provide a source of epidermal cells for skin tissue engineering applications in vitro or in vivo.

Exogenous nitric oxide enhances the synthesis of type I collagen and heat shock protein 47 by normal human dermal fibroblasts

BACKGROUND

It is well established that the alterations of dermal matrix contributes to skin aging characterized by wrinkles. On the other hand, physiological NO is useful to maintain skin homeostasis such as a vasodilatation. However, a role of NO on production of dermal matrix has been clarified.

OBJECTIVE

In this study, we have attempted to analyze the role of NO on type I collagen synthesis of normal human dermal fibroblasts including expression of procollagen alphaI S(1) mRNA/protein and heat shock protein 47 (HSP47).

METHODS

The effects of NO which was generated by two types of NO donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP), on type I collagen and HSP47 and their related mRNA expression were examined with ELISA and RT-PCR.

RESULTS

NO was significantly accelerated the production of type I collagen by fibroblasts corresponding with up-regulation of procollagen alphaI (1) mRNA. Furthermore, NO increased both levels of HSP47 protein and mRNA in fibroblasts in a dose-dependent manner.

CONCLUSIONS

These results suggest that NO has dual effects on collagen synthesis by fibroblasts as follows; one is the direct stimulation of collagen synthesis due to the up-regulation of procollagen alphaI(1) mRNA, and the other is an indirect effect through the increase of HSP47 mRNA expression. This is the first report that exogenous NO stimulates HSP47 production by dermal fibroblasts.

MCP-1 overexpressed in tuberous sclerosis lesions acts as a paracrine factor for tumor development

Patients with tuberous sclerosis complex (TSC) develop hamartomatous tumors showing loss of function of the tumor suppressor TSC1 (hamartin) or TSC2 (tuberin) and increased angiogenesis, fibrosis, and abundant mononuclear phagocytes. To identify soluble factors with potential roles in TSC tumorigenesis, we screened TSC skin tumor–derived cells for altered gene and protein expression. Fibroblast-like cells from 10 angiofibromas and five periungual fibromas produced higher levels of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein than did fibroblasts from the same patient's normal skin. Conditioned medium from angiofibroma cells stimulated chemotaxis of a human monocytic cell line to a greater extent than conditioned medium from TSC fibroblasts, an effect blocked by neutralizing MCP-1–specific antibody. Overexpression of MCP-1 seems to be caused by loss of tuberin function because Eker rat embryonic fibroblasts null for Tsc2 (EEF Tsc2^−/−) produced 28 times as much MCP-1 protein as did EEF Tsc2^+/+ cells; transient expression of WT but not mutant human TSC2 by EEF Tsc2^−/− cells inhibited MCP-1 production; and pharmacological inhibition of the Rheb-mTOR pathway, which is hyperactivated after loss of TSC2, decreased MCP-1 production by EEF Tsc2^−/− cells. Together these findings suggest that MCP-1 is an important paracrine factor for TSC tumorigenesis and may be a new therapeutic target.

Type I collagen synthesis parallels the conversion of keratinocytic intraepidermal neoplasia to cutaneous squamous cell carcinoma

Neoplastic progression of solid tumours is often characterized by a simultaneous increase in matrix protein (eg collagen) synthesis and degradation, and results in the formation of a tumour stroma. At the tumour periphery, this process is believed to facilitate angiogenesis and invasive growth of tumour cells. In various types of carcinoma, differentiation of fibroblasts towards myofibroblasts is thought to play an important role in extracellular matrix remodelling as their emergence coincides with architectural changes in the tumour stroma. Here, distinct architectural changes in collagen fibres are reported in cutaneous squamous cell carcinomas (cSCC) with respect to normal skin and precursor lesions, ie keratinocytic intraepidermal neoplasia (KIN). Simultaneously, type I collagen mRNA was observed in fibroblasts in close proximity to cSCC lesions (19/19) but only in 2 of 10 KIN lesions tested. Interestingly, whereas emerging of myofibroblasts correlated with reduced differentiation of cSCCs, it was not a prerequisite for type I collagen synthesis. These data indicate that type I collagen synthesis by fibroblasts parallels the malignant transformation of human KIN to cSCC.