Identification and Expression Analyses of the Special 14-3-3 Gene Family in Papaya and its Involvement in Fruit Development, Ripening, and Abiotic Stress Responses.

Plant 14-3-3 proteins play key roles in regulating growth, development, and stress responses. However, little is known about this gene family in papaya (Carica papaya L.). We characterized eight 14-3-3 genes from the papaya genome and designed them as CpGRF1-8. Based on phylogenetic, conserved motif, and gene structure analyses, papaya CpGRFs were divided into ε and non-ε groups. Expression analysis showed differential and class-specific transcription patterns in different organs. Quantitative real-time polymerase chain reaction analysis showed that most CpGRFs had large changes in expression during fruit development and ripening. This indicated that the CpGRFs were involved in regulating fruit development and ripening. Significant expression changes occurred after cold, salt, and drought treatments in papaya seedlings, indicating that CpGRFs were also involved in signaling responses to abiotic stress. These results provide a transcription profile of 14-3-3 genes in organs, during fruit development and ripening and in response to stress. Some highly expressed, fruit-specific, and stress-responsive candidate CpGRFs will be identified for further genetic improvement of papayas.

linc00174-EZH2-ZNF24/Runx1-VEGFA Regulatory Mechanism Modulates Post-burn Wound Healing.

Preservation of denatured dermis exerts promotive functions in wound healing and improves the appearance and function of skin. Angiogenesis is crucial for wound healing during burn injury. However, the potential molecular mechanism of angiogenesis in the recovery after burn injury remains to be elucidated. Herein, RNA chromatin immunoprecipitation (ChIP) sequencing analysis revealed upregulation of long intergenic non-coding RNA 00174 (linc00174) in the post-burn tissues. linc00174 overexpression promoted angiogenic activities of human umbilical vein endothelial cells (HUVECs) in the heat-denatured cell model, characterized by the promotion of cell proliferation, migration, and tube formation. Mechanistically, linc00174 directly bound to enhancer of zeste homolog 2 (EZH2), thus stimulating the protein level of trimethylation at lysine 27 of histone H3 (H3K27me3). Moreover, inhibition of EZH2 resulted in downregulation of ZNF24 and Runx1, as well as a decline of vascular endothelial growth factor A (VEGFA). Furthermore, EZH2 modulated epigenetic repression of ZNF24 and Runx1 through the promoter of H3K27me3. Additionally, ZNF24 and Runx1 both functioned as transcriptional inhibitors of VEGFA. Taken together, these findings uncover that linc00174 epigenetically inhibits ZNF24 and Runx1 expression through binding to EZH2, thus attenuating the suppression of VEGFA, contributing to the facilitation of angiogenesis during the recovery of heat-denatured endothelial cells.

Evolution of External Health Costs of Electricity Generation in the Baltic States.

Implementation of strict policies for mitigating climate change has a direct impact on public health as far as the external health costs of electricity generation can be reduced, thanks to the reduction of emission of typical pollutants by switching to cleaner low carbon fuels and achieving energy efficiency improvements. Renewables have lower external health costs due to the lower life cycle emission of typical air pollutants linked to electricity generation, such as SO2, NOx, particulate matter, NH3, or NMVOC (Non-methane volatile organic compounds), which all appear to have serious negative effects on human health. Our case study performed in the Baltic States analyzed the dynamics of external health costs in parallel with the dynamics of the main health indicators in these countries: life expectancy at birth, mortality rates, healthy life years, self-perceived health, and illness indicators. We employed the data for external health costs retrieved from the CASES database, as well as the health statistics data compiled from the EUROSTAT database. The time range of the study was 2010-2018 due to the availability of consistent health indicators for the EU Member States. Our results show that the decrease of external health costs had a positive impact on the increase of the self-perceived good health and reduction of long-standing illness as well as the decrease of infant death rate. Our conclusions might be useful for other countries as well as for understanding the additional benefits of climate change mitigation policies and tracking their positive health impacts. The cooperation initiatives on clean energy and climate change mitigation between countries like One Belt One Road initiative by the Chinese government can also yield additional benefits linked to the public health improvements.

Identification, Expression, and Interaction Network Analyses of the CDPK Gene Family Reveal Their Involvement in the Development, Ripening, and Abiotic Stress Response in Banana.

Calcium-dependent protein kinases (CDPKs) play vital roles in the regulation of plant growth, development, and tolerance to various abiotic stresses. However, little information is available for this gene family in banana. In this study, 44 CDPKs were identified in banana and were classified into four groups based on phylogenetic, gene structure, and conserved motif analyses. The majority of MaCDPKs generally exhibited similar expression patterns in the different tissues. Transcriptome analyses revealed that many CDPKs showed strong transcript accumulation at the early stages of fruit development and postharvest ripening in both varieties. Interaction network and co-expression analysis further identified some CDPKs-mediated network that was potentially active at the early stages of fruit development. Comparative expression analysis suggested that the high levels of CDPK expression in FJ might be related to its fast ripening characteristic. CDPK expression following the abiotic stress treatments indicated a significant transcriptional response to osmotic, cold, and salt treatment, as well as differential expression profiles, between BX and FJ. The findings of this study elucidate the transcriptional control of CDPKs in development, ripening, and the abiotic stress response in banana. Some tissue-specific, development/ripening-dependent, and abiotic stress-responsive candidate MaCDPK genes were identified for further genetic improvement of banana.

Epidemiology and outcome analysis of facial burns: A retrospective multicentre study 2011-2015.

BACKGROUND: The head and neck regions are frequent sites of burns, but few studies have analysed and reported the epidemiology of facial burns. As the face is the centre of one's identity and persona, facial injuries often result in physical and psychological morbidity. The aim of this article is to describe the epidemiology and outcome of facial burns in China and to suggest future preventive strategies. METHODS: This retrospective analysis included all patients with facial burns in a database at eight institutions from 2011-2015. The data collected included sex, age, month distribution, aetiology, location, presence of inhalation injury, total burn surface area, burn surface area with full-thickness and outcome including Post-traumatic stress disorder Checklist-Civilian Version scores and mortality. SPSS 19.0 software was used to analyse the data. RESULTS: A total of 1126 patients were included; 65.63% (739) had facial burns, of which 546 (73.88%) were male patients and 193 (26.12%) were female patients. Predictors of facial burns were being of male sex, working-related place, flame burns, total body surface area, and full-thickness burns. In addition, total body surface area and full-thickness burns increased the risk of poor prognosis for post-traumatic stress disorder and mortality. CONCLUSIONS: Facial burns benefit not only the healing of wound, but also the prevention of their incidence and PTSD symptom. This study may contribute to the elaboration of strategies to prevent facial burns and the establishment of a nationwide burn database in China.

Expression changes in protein-coding genes and long non-coding RNAs in denatured dermis following thermal injury.

OBJECTIVE: Thermal injury repair is a complex process during which maintaining the proliferation of human dermis fibroblasts (HDFs) and synthesis of extracellular matrix (ECM) plays a critical role. In the present study, we analyzed potential molecular markers and the probable association between differentially-expressed lncRNAs and protein-coding genes within denatured dermis following thermal injury, attempting to provide further insights to thermal injury repair pathogenesis. METHODS AND MAIN RESULTS: We found that the expression of 3940 lncRNAs was increased, while that of 1438 lncRNAs was reduced in the denatured dermis following thermal injury when compared to normal tissue. Of them, 338 were upregulated and 154 were downregulated by more than 128 times. Via cross-check with another microarray profile analysis on differentially-expressed lncRNAs after thermal injury, LINC00302 was found to be downregulated after thermal injury; more importantly, this skin-specially expressed lncRNA is located near a series of genes related to multiple skin inflammation and skin barrier-associated genomes. LINC00302 overexpression promoted the cell viability and the protein levels of α-SMA and Collagen I in HDFs. CONCLUSIONS: In conclusion, mRNAs and lncRNAs could be differentially expressed in the denatured dermis following thermal injury. mRNA and lncRNA regulatory signaling pathways could participate in thermal injury repair pathogenesis. More importantly, LINC00302 may play a critical role in thermal injury repair.

[Experience of diagnosis and treatment for 89 patients with Marjolin's ulcers in lower limbs].

OBJECTIVE: To summarize the clinical features of Marjolin's ulcers in lower limbs and the diagnosis and treatment methods for it.
 Methods: The clinical data of 89 patients with lower limbs Marjolin's ulcers, who were treated in Xiangya Hospital, Central South University from Jan 1998 to Dec 2017, were retrospectively analyzed, including demographics, injury factors, length of cancer incubation period, lesion location, ulcer area, pathological type, bone invasion, lymph node metastasis, surgical methods, repair methods and prognosis.
 Results: There were 70 males and 19 females among 89 patients with lower limbs Marjolin's ulcers. The most common injuries were flame burn (42 cases), trauma (19 cases), and burns (12 cases). The lesions were most common in the lower leg (31 cases), followed by the thigh (11 cases) and the heel (11 cases). The ulcer area was 1.5-600.0 cm2. There were 80 cases of squamous cell carcinoma, 8 cases of verrucous carcinoma, and 1 case of sarcoma. Before operation, 78 cases of inguinal lymphadenectasis were found, 49 cases of inguinal lymph node dissection, 29 cases of simple lymph node biopsy and resection, and 9 cases of lymph node metastasis and 8 cases of bone invasion were observed; 24 cases of amputation, 53 cases of extended resection and skin grafts, and 12 patients of extensive resection and flap transplantation were performed. Sixty-five cases were followed up, and 8 cases recurred, including 2 cases of amputation patients and 6 cases of extended resection patients. There was no relationship between recurrence of tumors and surgical methods (P>0.05).
 Conclusion: The recurrence and metastasis rate of Marjolin's ulcers in lower limbs is high, requiring early detection, early diagnosis, early surgical treatment and regular follow-up. Lnguinal lymphadenectasis is more common and requires lymph node biopsy and lymphadenectomy, or lymph node dissection. Extended local resection, skin graft or flap repair is the main treatment methods. However, amputation can be considered if the cancer is big, the invasion is deep, and the lower extremity scar is extensive and combined with severe deformity.

Comprehensive Analysis of Long Noncoding RNAs and Messenger RNAs Expression Profiles in Patients with Marjolin Ulcer.

BACKGROUND Marjolin ulcer (MU) is an aggressive cutaneous malignancy. Typically, MU occurs over a period of time in post-burn and/or post-traumatic lesions and scars. However, the pathogenesis of scar carcinogenesis and MU development remains to be elucidated. The present study aimed to investigate the long noncoding RNA (lncRNA) and messenger RNA (mRNA) expression profiling in MU, which could provide new information on the potential molecular mechanisms of MU development. MATERIAL AND METHODS The lncRNA microarray analysis was conducted in normal skin, scar, and MU tissue, and quantitative real-time PCR experiment was carried out to validate the reliability of the microarray data. Furthermore, a series of integrative bioinformatic approaches were applied to decipher the function of differentially expressed lncRNAs. RESULTS A total of 7130 lncRNAs and 9867 mRNAs were differentially expressed among normal skin, scar, and MU tissues. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated that these aberrantly expressed transcripts were mainly involved in cell cycle, immune response, and the p53 signaling pathway. Series Test of Cluster analysis indicated certain dysregulated lncRNAs were expressed with a gradually increasing or decreasing trend and might participated in malignant transformation of scar tissue postburn. Co-expression analysis showed 5 selected lncRNAs might regulate cell proliferation through the p53 signaling pathway. Finally, the competing endogenous RNA (ceRNA) network indicated that lncRNA uc001oou.3 might be implicated in ceRNA mechanism during MU development. CONCLUSIONS Taken together, our study implied the aberrant expression of lncRNAs may play an important role in the pathogenesis and development of MU, and the exact mechanism warrants further investigation.

Epidemiologic and clinical characteristics of severe burn patients: results of a retrospective multicenter study in China, 2011-2015.

BACKGROUND: Severe burns injury is a serious pathology, leading to teratogenicity and significant mortality, and it also has a long-term social impact. The aim of this article is to describe the hospitalized population with severe burns injuries in eight burn centers in China between 2011 and 2015 and to suggest future preventive strategies. METHODS: This 5-year retrospective review included all patients with severe burns in a database at eight institutions. The data collected included gender, age, month distribution, etiology, location, presence of inhalation injury, total burn surface area, depth of the burn, the length of hospitalization, and mortality. SPSS 19.0 software was used to analyze the data. RESULTS: A total of 1126 patients were included: 803 (71.3%) male patients and 323 (28.7%) female patients. Scalds were the most common cause of burns (476, 42.27%), followed by fire (457, 40.59%). The extremities were the most frequently affected areas, followed by the trunk. The median length of hospitalization was 30 (15, 52) days. The overall mortality rate was 14.21%. CONCLUSIONS: Although medical centers have devoted intensive resources to improving the survival rates of burn patients, expenditures for prevention and education programs are minimal. Our findings suggest that more attention should be paid to the importance of prevention and the reduction of injury severity. This study may contribute to the establishment of a nationwide burn database and the elaboration of strategies to prevent severe burns injury.

MiR-128-3p directly targets VEGFC/VEGFR3 to modulate the proliferation of lymphatic endothelial cells through Ca2+ signaling.

Lymphangiogenesis has been regarded as a physiological response to pathologic stimuli. The abnormal proliferation of lymphatic endothelial cell (LECs) and lymphangiogenesis is involved in the development of lymphatic disorders. Reportedly, VEGFC/VEGFR3 plays a key role in lymphangiogenesis; moreover, VEGFC/VEGFR3 exerts their cellular effects through activation of Ca2+ signaling in several cell types. Herein, we demonstrated that VEGFC significantly up-regulated LEC proliferation through VEGFR3; moreover, VEGFC/VEGFR3 induced Ca2+ signaling activation. By using online tools, miR-128 and miR-3916 were predicted as candidate upstream miRNAs which might target VEGFC/VEGFR3. As verified using Immunoblotting assays, miR-128 significantly regulated the protein levels of VEGFC/VEGFR3, whereas miR-3916 only slightly modulated VEGFC and VEGFR3 proteins. Contrary to VEGFC, miR-128 overexpression remarkably suppressed LEC proliferation, Ca2+ release and ERK1/2-Akt signaling; moreover, the effect of VEGFC could be partially attenuated by miR-128. In summary, miR-128 interacts with the 3'-UTR of VEGFC and VEGFR3 to inhibit their expression, thus suppressing LEC proliferation through Ca2+ and ERK1/2-Akt signaling. Taken together, we provided novel experimental basis for miRNA-regulated LEC proliferation through Ca2+ signaling.

Role of XIST/miR-29a/LIN28A pathway in denatured dermis and human skin fibroblasts (HSFs) after thermal injury.

Denatured dermis is a part of the dermis in deep burn wound and has the ability to restore normal morphology and function. In our previous study, we revealed that miR-29a downregulation in denatured dermis may help burn wound healing in the later phase, and further enhance type I collagen synthesis. LIN28A, a highly-conserved RNA binding protein expressed during embryogenesis, plays roles in development, pluripotency, metabolism, as well as tissue repair in adults. In the present study, we investigated the functional roles of LIN28A in human skin fibroblasts (HSFs) and extracellular matrix (ECM), and the interaction between miR-29a and LIN28A. In recent years, long non-coding RNAs have been reported to play a key role in normal development and physiology, as well as in disease development. By using online tools, we screened out several candidate lncRNAs of miR-29a, among which XIST was inversely regulated by miR-29a. XIST, one of the first found cancer-associated lncRNAs, has been frequently reported to play major role in several biological processes. Further, we evaluated the roles and mechanism of XIST in HSF proliferation, migration, and ECM synthesis. Through regulation of miR-29a/LIN28A, XIST knockdown suppressed HSF proliferation, migration, and ECM synthesis. In denatured dermis tissues, XIST, and LIN28A expression was upregulated, miR-29a expression was downregulated. Taken together, promoting XIST expression in denatured dermis, thus to inhibit miR-29a and promote LIN28A expression, further promote HSF proliferation, migration, and ECM synthesis presents a promising strategy for denatured dermis repair.

Muscular proteomic profiling of deep pressure ulcers reveals myoprotective role of JAK2 in ischemia and reperfusion injury.

Pressure ulcers (PUs) are a complex and serious clinical problem. Deep tissue injury (DTI) is either the outcome or the trigger of deep PUs. However, the cellular and molecular mechanisms that contribute to the pathogenesis of deep PUs remain unclear. In this study, the degeneration characteristics and increased autophagy and apoptosis were observed in deep PU muscle tissues. Muscular proteome of deep PU revealed that a total of 520 proteins were differentially expressed, particularly, JAK2 was down-regulated. Intriguingly, expression of JAK2 in C2C12 myoblasts exposed to oxygen-glucose deprivation and reoxygenation (OGD/R) insult was also distinctly reduced. Ex vivo, we transfected C2C12 myoblasts with lentivirus carrying the JAK2 plasmid and found that JAK2-overexpressed myoblasts exhibited a decrease in autophagy and apoptosis after OGD/R treatment, as well as less cell death. Finally, Western blot analysis determined that p-JAK2, p-AKT, p-mTOR and p-ERK1/2 levels were significantly elevated, accompanied by JAK2 overexpression but without p-STAT3, and inhibition of the AKT and ERK1/2 pathway resulted in elevated apoptosis and/or autophagy. These results demonstrated that JAK2 may play an important protective role in muscular ischemia and reperfusion injury during DTI development by inhibition of autophagy and apoptosis through the AKT and ERK1/2 pathways.

Reconstruction of fingers after electrical injury using lateral tarsal artery flap.

OBJECTIVE: Electrical injuries to the fingers account for the majority of total severe burns that occur each year. While several types of flaps have been used in covering finger defects, all have limitations or disadvantages. The purpose of this study was to introduce our clinical experiences of using the lateral tarsal artery (LTA) flap to successfully restore fingers after electrical injury. PATIENTS AND METHODS: From 2005 to 2012, 10 patients with 14 severe electrical burns to their fingers, including six thumbs and four index and four middle fingers, were treated with LTA flap. The wound size ranged from 2.0×3.0 cm to 3.5×5.0 cm. The flap with free tendon graft was used to repair the tendon defect in four cases, free nerve graft was used to repair the feeling defect in two cases, and the flap with nerve was used to repair the feeling defect in two cases. All the patients were followed up for 3 months to 2 years. RESULTS: All skin flaps adhered successfully and there were no complications. All patients were satisfied with the esthetic appearance and functional outcome of the finger reconstruction. CONCLUSION: LTA flap is a reliable method to restore fingers after severe electrical injuries.

Early laparotomy and timely reconstruction for patients with abdominal electrical injury: Five Case Reports and Literature Review.

INTRODUCTION: High-tension electricity can cause devastating injuries that may result in abdominal wall loss, visceral damage, and sometimes major threat to life. The visceral organ may be exposed after debridement and require flap cover, but the tensile strength of abdominal wall may be lack even if flap transplanted. METHODS: From April 2007 through May 2015, 5 patients with severe abdominal electrical injury were treated at our hospital. Exploratory laparotomy was performed based on their clinical manifestations and debridement findings of abdominal wall at early stage, and decision regarding technique for reconstruction of abdominal wall was based on an assessment of the location and extent of the defect. Medical records were reviewed for these data. RESULTS: Clinical evaluation and debridement findings of the abdomen revealed 4 patients with suspicious visceral damage. Laparotomy was performed in 4 cases, and revealed obvious lesion in 3 cases, including segmental necrosis of small intestine, partial necrosis of diaphragm, left liver and gastric wall, and greater omentum. Five patients underwent abdominal wall reconstruction using island retrograde latissimus dorsi myocutaneous flap or free/island composite anterolateral thigh myocutaneous flap. All flaps survived, abdominal bulging occurred in 3 cases after follow-up of 12 to 36 months. CONCLUSIONS: The clinical manifestations and wound features of abdomen collectively suggest a possible requirement of laparotomy for severe abdominal electrical burns. Retrograde latissimus dorsi myocutaneous flap or composite anterolateral thigh myocutaneous flap is an effective option for reconstruction of abdominal wall loss, the long-term complication of abdominal bulging, however, remains a significant clinical challenge.

Genome-Wide Identification, Phylogeny, and Expression Analyses of the 14-3-3 Family Reveal Their Involvement in the Development, Ripening, and Abiotic Stress Response in Banana.

Plant 14-3-3 proteins act as critical components of various cellular signaling processes and play an important role in regulating multiple physiological processes. However, less information is known about the 14-3-3 gene family in banana. In this study, 25 14-3-3 genes were identified from the banana genome. Based on the evolutionary analysis, banana 14-3-3 proteins were clustered into ε and non-ε groups. Conserved motif analysis showed that all identified banana 14-3-3 genes had the typical 14-3-3 motif. The gene structure of banana 14-3-3 genes showed distinct class-specific divergence between the ε group and the non-ε group. Most banana 14-3-3 genes showed strong transcript accumulation changes during fruit development and postharvest ripening in two banana varieties, indicating that they might be involved in regulating fruit development and ripening. Moreover, some 14-3-3 genes also showed great changes after osmotic, cold, and salt treatments in two banana varieties, suggested their potential role in regulating banana response to abiotic stress. Taken together, this systemic analysis reveals the involvement of banana 14-3-3 genes in fruit development, postharvest ripening, and response to abiotic stress and provides useful information for understanding the functions of 14-3-3 genes in banana.

[Analysis of clinical characteristics of 187 patients with Marjolin's ulcers].

OBJECTIVE: To analyze the etiology and clinical characteristics of Marjolin's ulcer, and to explore its prevention and treatment. METHODS: Medical records of 187 patients with Marjolin's ulcers admitted to the Department of Burns and Reconstructive Surgery of Xiangya Hospital of Central South University from January 1998 to May 2015 were retrospectively analyzed, including gender, age of onset of initial injury or primary disease, age of onset of Marjolin's ulcer, initial injury or primary disease, length of latency, lengths of pre- and post-ulceration periods, lesion site, lesion type, lesion area, local scar tension, histopathological type, degree of carcinoma cell differentiation, bone invasion and lymphadenopathy, treatment, and prognosis. The relationships between the age of onset of initial injury or primary disease and the length of latency, and the length of pre-ulceration period and the length of post-ulceration period were assessed by Spearman correlation analysis. The recurrence rates were processed with Fisher's exact test. RESULTS: (1) Among the patients, the ratio of male to female was nearly 1.6:1.0. The age of onset of initial injury or primary disease was 0.17-78.00 (17±18) years, and the age of onset of Marjolin's ulcers was 18-84 (49±14) years. (2) The most common initial injury among the patients was flame burn. The length of latency was 0.25-74.00 (32±16) years, and the lengths of pre- and post-ulceration periods were 0-73.00 (26±19) years and 0.08-59.00 (6±11) years respectively. The common lesion sites were the lower limbs and head and face. The rodent ulcer was the most common lesion type, and the lesion area was 1-625 (69±110) cm(2). There were obviously negative correlations between the age of onset of initial injury or primary disease and the length of latency, as well as the length of pre-ulceration period and the length of post-ulceration period (with r values respectively -0.71 and -0.50, P values below 0.01). The pathological scars of strong tension around lesions were seen in 176 cases. (3) The major histopathological type was squamous cell carcinoma, with high cell differentiation in most cases. (4) Bone invasion of carcinoma cells was observed in 59 cases. Lymph node enlargement was observed in 100 cases, and lymph node metastasis was observed in 18 cases. (5) Twenty patients did not receive any surgery, while 167 patients were treated by surgery with lesion extended resection as the main method. According to the condition of wound after the lesion extended resection, the wounds were mainly repaired by skin grafting and transplantation of local skin flap. The majority of wounds in 139 patients who underwent lesion extended resection were repaired in one surgery. Twenty-eight patients out of 104 followed-up cases had recurrence after surgery, mainly seen on head and face, upper limb, lower limb, and buttock, and there was no significant difference among them (P>0.05). The recurrence time of most patients was longer than 6 months after cure. CONCLUSIONS: Patients with Marjolin's ulcers in younger age of onset of initial injury or primary disease tend to have longer latency, during which the shorter the pre-ulceration period is, the longer the post-ulceration period will be. Marjolin's ulcers are prone to occur in scar sites with large tension. Early treatment of high tension scar and scar ulcer is important in prevention, and surgery is the optimal treatment for Marjolin's ulcers. Regular follow-up should be carried out owning to recurrence rate in certain degree after surgery.

[Changes in the expression of three markers in T lymphocytes of peripheral blood and immunoregulatory mechanisms of burned mice with sepsis at early stage].

OBJECTIVE: To study the expression levels of annexin A1 (ANXA1), GATA-3, and T-bet in T lymphocytes of peripheral blood in burned mice with sepsis at early stage, and to analyze their immune regulatory mechanisms. METHODS: Seven-hundred and eighty male mice of clean grade were divided into sham injury group (n=60, sham injured on the back by immersing in 37 ℃ warm water for 10 s), burn group (n=240, inflicted with 20% TBSA deep partial- thickness burn on the back by immersing in 100 ℃ hot water for 10 s), sepsis group (n=240, intraperitoneally injected with 6 mg/kg lipopolysaccharide), and burn+ sepsis group (n=240) according to the random number table. Mice of burn+ sepsis group were treated as that in burn group at first, and then they were treated as that in sepsis group. (1) Immediately after injury, six mice in sham injury group were selected to collect lymphocyte suspension of peripheral blood (1 tube each mouse) according to the random number table. According to the random number table, 6 mice of each of the other three groups were respectively selected at post injury hour (PIH) 12, 24, 48, and 72 for the collection of lymphocyte suspension from peripheral blood (1 tube each mouse). Each tube of cell suspension was equally divided into two parts. Fluorescein isothiocyanate (FITC)-labeled human anti-mouse CD4 monoclonal antibody and phycoerythrin (PE)-labeled human anti-mouse interferon-γ monoclonal antibody were added to one part of cell suspension to mark helper T lymphocyte 1 (Th1). FITC-labeled human anti-mouse CD4 monoclonal antibody and PE-labeled human anti-mouse interleukin-4 (IL-4) monoclonal antibody were added to the other part of cell suspension to mark Th2. The percentages of Th1 and Th2 were determined with flow cytometer, and the ratio of Th1 to Th2 was calculated. (2) According to the random number table, 18 mice in sham injury group were selected immediately after injury for the collection of lymphocyte suspension of peripheral blood (1 tube each mouse), and 18 mice of each of the other 3 groups were respectively selected at PIH 12, 24, 48, and 72 to collect the lymphocyte suspension of peripheral blood (1 tube each mouse). The mRNA expression levels of ANXA1, GATA-3, and T-bet were determined by real-time fluorescent quantitative reverse transcription-PCR. (3) Immediately after injury, 36 mice in sham injury group were selected to collect lymphocyte suspension of peripheral blood (1 tube each mouse) according to the random number table, and then 36 tubes of cell suspension were divided into 6 batches (6 tubes each batch). Each one of 6 kinds of antibody combinations: antibodies for labeling Th1 and Th2 in combination with PE-anthocyanin 7 labeled human anti-mouse ANXA1 monoclonal antibody, PE-anthocyanin 7 labeled human anti-mouse GATA-3 monoclonal antibody, and PE-anthocyanin 7 labeled human anti-mouse T-bet monoclonal antibody was added to 1 tube of cell suspension at each batch. According to the random number table, 36 mice of each of the other 3 groups were respectively selected at PIH 12, 24, 48, and 72 for the collection of lymphocyte suspension of peripheral blood (1 tube each mouse), and then 36 tubes of cell suspension at each time point were divided into 6 batches for marking with 3 kinds of surface markers of Th1 and Th2 (6 tubes each batch). Each one of above-mentioned 6 kinds of antibodies was added to 1 tube of cell suspension at each time point for each batch. The percentages of ANXA1, GATA-3, and T-bet positive cells in Th1 and Th2 were determined with flow cytometer. Data were processed with one-way analysis of variance, analysis of variance of factorial design, and SNK test. The relationship between the percentages of ANXA1 positive cell and the percentages of GATA-3 positive cell in Th1 and Th2, and mRNA expression level of ANXA1 and mRNA expression level of GATA-3 in lymphocytes were assessed by linear correlation analysis. RESULTS: (1) Compared with those in sham injury group immediately after injury, the percentages of Th1 and Th2 and the ratio of Th1 to Th2 of mice in burn group were significantly decreased from PIH 24 on, with P values below 0.05; the percentages of Th1 and Th2 and the ratios of Th1 to Th2 of mice in sepsis group and burn+ sepsis group were significantly decreased from PIH 12 on, with P values below 0.05. (2) Compared with those in sham injury group immediately after injury, the mRNA expression levels of ANXA1 and GATA-3 in lymphocyte of mice in burn group were significantly decreased from PIH 24 on, with P values below 0.05; the mRNA expression level of T-bet was significantly decreased at PIH 24 but significantly increased at PIH 48 and 72, with P values below 0.05. Compared with those in sham injury group immediately after injury, the mRNA expression levels of ANXA1 and GATA-3 in lymphocytes of mice in sepsis group were significantly decreased from PIH 12 on, and the mRNA expression level of T-bet was increased significantly from PIH 12 on, with P values below 0.05; the mRNA expression levels of ANXA1, GATA-3, and T-bet in lymphocytes of mice in burn+ sepsis group were significantly decreased from PIH 12 on, with P values below 0.05, reaching the nadir at PIH 72 (0.50±0.04, 0.45±0.03, 0.21±0.05, respectively). (3) A significant positive correlation was observed between ANXA1 mRNA expression level and GATA-3 mRNA expression level in lymphocytes of peripheral blood (r=0.862, P<0.05). (4) Compared with those in sham injury group immediately after injury, the percentages of ANXA1 and GATA-3 positive cellsin Th1 and Th2 of mice in burn group were significantly lowered from PIH 24 on, and the percentage of T-bet positive cells was significantly decreased at PIH 24, but it was increased from PIH 48 on, with P values below 0.05. The percentages of ANXA1 and GATA-3 positive cells in Th1 and Th2 of mice in sepsis group were continuously decreased from PIH 12 on, which were lower at most time points than those in sham injury group immediately after injury, with P values below 0.05. The percentages of T-bet positive cells in Th1 and Th2 of mice in sepsis group were significantly increased since PIH 12 as compared with those in sham injury group immediately after injury, with P values below 0.05. The percentages of ANXA1, GATA-3, and T-bet positive cells in Th1 and Th2 of mice in burn+ sepsis group were continuously lowered from PIH 12, with significantly statistical differences at most time points as compared with those in sham injury group immediately after injury, with P values below 0.05. (5) The percentages of GATA-3 positive cells in Th1 and Th2 were significantly positively correlated with those of ANXA1 (with r values respectively 0.747 and 0.787, P values below 0.05). CONCLUSIONS: The expression levels of ANXA1, GATA-3, and T-bet were continuously lowered in burned mice with sepsis, and it may play an important role in Th1/Th2 balance switching to Th2 bias and immunosuppressive process.

Protective role of microRNA-29a in denatured dermis and skin fibroblast cells after thermal injury.

Our previous study has suggested that downregulated microRNA (miR)-29a in denatured dermis might be involved in burn wound healing. However, the exact role of miR-29a in healing of burn injury still remains unclear. Here, we found that expression of miR-29a was notably upregulated in denatured dermis tissues and skin fibroblast cells after thermal injury, and thereafter gradually downregulated compared with control group. By contrast, the expression of collagen, type I, alpha 2 (COL1A2) and vascular endothelial growth factor (VEGF-A) were first reduced and subsequently upregulated in denatured dermis tissues and skin fibroblast cells after thermal injury. We further identified COL1A2 as a novel target of miR-29a, which is involved in type I collagen synthesis, and showed that miR-29a negatively regulated the expression level of COL1A2 in skin fibroblast cells. In addition, VEGF-A, another target gene of miR-29a, was also negatively mediated by miR-29a in skin fibroblast cells. Inhibition of miR-29a expression significantly promoted the proliferation and migration of skin fibroblast cells after thermal injury, and knockdown of COL1A2 and VEGF-A reversed the effects of miR-29a on the proliferation and migration of skin fibroblast cells. Furthermore, we found that Notch2/Jagged2 signaling was involved in miR-29a response to burn wound healing. Our findings suggest that downregulated miR-29a in denatured dermis may help burn wound healing in the later phase, probably via upregulation of COL1A2 and VEGF-A expression, which can further enhance type I collagen synthesis and angiogenesis.

Myofibroblasts contribute to but are not necessary for wound contraction.

Wound contraction facilitates tissue repair. The correct balance between too little contraction, which leads to non-healing wounds, and too much contraction, which leads to contractures, is important for optimal healing. Thus, understanding which cells cause wound contraction is necessary to optimize repair. Wound contraction is hypothesized to develop from myofibroblast (cells which express alpha-smooth muscle actin; ACTA2) contractility, while the role of fibroblast contractility is unknown. In this study, we utilized ACTA2 null mice to determine what role fibroblasts play in wound contraction. Human scar contractures were immunostained for ACTA2, beta-cytoplasmic actin (ACTB), and gamma-cytoplasmic actin (ACTG1). Full-thickness cutaneous wounds were created on dorsum of ACTA2(+/+) mice and strain-matching ACTA2(+/-) and ACTA2(-/-) mice. Wound contraction was quantified. Tissue was harvested for histologic, immunohistochemical and protein analysis. Compared with surrounding unwounded skin, human scar tissue showed increased expression of ACTA2, ACTB, and ACTG1. ACTA2 was focally expressed in clusters. ACTB and ACTG1 were widely, highly expressed throughout scar tissue. Wound contraction was significantly retarded in ACTA2(-/-) mice, as compared to ACTA2(+/+) controls. Control mice had increased epithelialization, cell proliferation, and neovascularization. ACTA2(-/-) mice had lower levels of apoptosis, and fewer total numbers of cells. Smaller amount of collagen deposition and immature collagen organization in ACTA2(-/-) mice demonstrate that wounds were more immature. These data demonstrate that myofibroblasts contribute to but are not necessary for wound contraction. Mechanisms by which fibroblasts promote wound contraction may include activation of contractile signaling pathways, which promote interaction between non-muscle myosin II and ACTB and ACTG1.