Idiopathic pulmonary fibrosis (IPF), a chronic interstitial lung disease, is characterized by aberrant wound healing, excessive scarring and the formation of myofibroblastic foci. Although the role of alternative splicing (AS) in the pathogenesis of organ fibrosis has garnered increasing attention, its specific contribution to pulmonary fibrosis remains incompletely understood. In this study, we identified an up-regulation of serine/arginine-rich splicing factor 7 (SRSF7) in lung fibroblasts derived from IPF patients and a bleomycin (BLM)-induced mouse model, and further characterized its functional role in both human fetal lung fibroblasts and mice. We demonstrated that enhanced expression of Srsf7 in mice spontaneously induced alveolar collagen accumulation. Mechanistically, we investigated alternative splicing events and revealed that SRSF7 modulates the alternative splicing of pyruvate kinase (PKM), leading to metabolic dysregulation and fibroblast activation. In vivo studies showed that fibroblast-specific knockout of Srsf7 in conditional knockout mice conferred resistance to bleomycin-induced pulmonary fibrosis. Importantly, through drug screening, we identified lomitapide as a novel modulator of SRSF7, which effectively mitigated experimental pulmonary fibrosis. Collectively, our findings elucidate a molecular pathway by which SRSF7 drives fibroblast metabolic dysregulation and propose a potential therapeutic strategy for pulmonary fibrosis.

Objective　To investigate the contamination status of Bacillus cereus in food, the profile of virulence factors carried, and drug sensitivity characteristics in Liaoning Province. Methods　A total of 620 samples were isolated from 15 monitoring sites, covering four major sample types of food products in Liaoning Province between 2021 and 2022. Bacillus cereus was isolated and identified by GB4789.14—2014, and its virulence was assessed using PCR detection of the groEL and gyrB genes specific to the bacterial group, as well as 11 other virulence genes. Broth microdilution method was used to detect the antibiotic sensitivity of the strain. Results　All 79 Bacillus cereus strains were found to carry virulence genes. The detection rates of non-hemolytic enterotoxin genes nheC, nheA, and nheB were 100% (79/79), 93.3% (74/79), and 83.5% (66/79), respectively. The detection rate of enterotoxin entFM gene was 98.7% (78/79). The 79 strains of Bacillus cereus carried 19 types of virulence gene patterns, with IX and XVII gene patterns being the most prevalent, each accounted for 16.5% (13/79). The resistance rates of 79 strains of Bacillus cereus to 10 antibacterial drugs were 100% for both ampicillin and penicillin. The resistance rates to cotrimoxazole, imipenem, erythromycin, clindamycin, ciprofloxacin, and tetracycline 65.8% (52/79), 10.1% (8/79), 73.4% (58/79), 60.8% (48/79), 75.9% (60/79), and 70.9% (56/79) respectively. The resistance rates to chloramphenicol and gentamicin were both 0%. Conclusion　Food from catering services in Liaoning Province shows contamination by Bacillus cereus, with isolated strains carrying at least four kinds of virulence genes. About 100% of the isolates were resistant to ampicillin and penicillin, whereas high sensitivity was observed to chloramphenicol and gentamicin. Active monitoring, timely targeted prevention and control interventions should be strengthened to provide a theoretical basis for future traceability studies.

Abstract: Objective　To analyze the molecular serotyping and drug resistance of foodborne Listeria monocytogenes (LM)isolates from the food monitoring network of Liaoning Province, and to provide a reference for identifying and tracing the outbreaks of foodborne diseases. Methods　The Listeria monocytogenes isolates were identified, biochemical typing was conducted by VITEK biochemical identification and PCR amplification techniques were applied for molecular serotyping of 67 strains of Listeria monocytogenes detected from 2 797 food samples collected from 15 monitoring sites across the province during 2021-2022. Verification was performed according to the instructions of the serodiagnosis manual. The sensitivity of the strains to ampicillin, penicillin, meropenem, cotrimoxazole, and erythromycin was determined by broth dilution method. Results　In food from Liaoning Province, the molecular serotypes of Listeria monocytogenes carried were identified as 1/2a(3a), 1/2b(3b, 7), 1/2c(3c), and 4b (4d, 4e), with the predominant serotypes being 1/2a accounting for 62.7% (42/67), and 1/2b accounting for 28.4% (19/67). Among them, the 4b strain was isolated in 3 strains, representing 4.5%. The dominant strains of Listeria monocytogenes in 2021 and 2022 in Liaoning Province were 1/2a(3a) and 1/2b(3b, 7), with the most diverse types carried by meat and meat products. Double resistance to cotrimoxazole and erythromycin accounted for 11.9% (8/67), while resistance to only one cotrimoxazole accounted for 9.0% (6/67). Conclusions　The presence of pathogenic serotypes 1/2a(3a), 1/2b(3b, 7), 1/2c(3c), and 4b (4d, 4e) in food in Liaoning Province and the emergence of strains with one or more drug resistances indicate the existence of food safety issues caused by Listeria monocytogenes, posing a potential risk of listeriosis. There is a need to optimize source tracing methods and strengthen the confirmation of Listeria monocytogenes outbreaks.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with unknown etiology and limited therapeutic options. Activation of fibroblasts is a prominent feature of pulmonary fibrosis. Here we report that lncRNA DACH1 (dachshund homolog 1) is downregulated in the lungs of IPF patients and in an experimental mouse model of lung fibrosis. LncDACH1 knockout mice develop spontaneous pulmonary fibrosis, whereas overexpression of LncDACH1 attenuated TGF-β1-induced aberrant activation, collagen deposition and differentiation of mouse lung fibroblasts. Similarly, forced expression of LncDACH1 not only prevented bleomycin (BLM)-induced lung fibrosis, but also reversed established lung fibrosis in a BLM model. Mechanistically, LncDACH1 binding to the serine/arginine-rich splicing factor 1 (SRSF1) protein decreases its activity and inhibits the accumulation of Ctnnb1. Enhanced expression of SRSF1 blocked the anti-fibrotic effect of LncDACH1 in lung fibroblasts. Furthermore, loss of LncDACH1 promoted proliferation, differentiation, and extracellular matrix (ECM) deposition in mouse lung fibroblasts, whereas such effects were abolished by silencing of Ctnnb1. In addition, a conserved fragment of LncDACH1 alleviated hyperproliferation, ECM deposition and differentiation of MRC-5 cells driven by TGF-β1. Collectively, LncDACH1 inhibits lung fibrosis by interacting with SRSF1 to suppress CTNNB1 accumulation, suggesting that LncDACH1 might be a potential therapeutic target for pulmonary fibrosis.

Objective To isolate the dedifferentiation-derived epidermal stem cells (DDESCs)to further investigate their phenotypic characteristics. Methods The sheets of human foreskin were digested overnight after removal of adipose tissues and then the epidermis was separated from the dermis.The epidermis sheets which eliminated basal stem cells by repeated adhesion to type Ⅳ collagen and flushing were transplanted onto the full-thickness skin wounds on the back of BALB/c nude mice. After five days, the sheets were collected and digested into single cells, after which the percentages of positive cells of CK10, CK19 and β1 integrin were detected by flow cytometric analysis. DDESCs were isolated by rapid adhesion to type Ⅳ collagen. The expressions of CK19, β1 integrin, Oct4 and Nanog in the cells were examined using immunofluorescence and quantitative real-time polymerase chain reaction (RTPCR). Results The percentages of positive cells of CK19 and 31 integrin were increased (P ＜0.01 )and those of CK10 in the transplanted sheets decreased ( P ＜0.01 ) five days after transplantation. Isolation of DDESCs by repeated adhesion to type Ⅳ collagen showed 4.56% adhering cells in the transplantation group within 10 minutes. The in vitro phenotypic assays showed that the expressions of CK19, β1 integrin, Oct4 and Nanog in DDESCs were similar to those of original epidermal stem cells ( P ＞0.05 ) but remarkably higher than those in the control group ( P ＜ 0.01 ). Conclusion The phenotypic characteristics of DDESCs cultured in vitro are similar to those of epidermal stem cells, indicating a new approach for wound repair and regeneration.

Objective To investigate the correlation between human epidermal stem cell (hESCs) and hypertrophic scar or keloid. Methods Improved collagen Ⅳ-coated adhesion methods was used to isolate and culture the epidermal stem cells after neutral protease selectively digested the dermo-epidermal junctions. After the cells were cultured and expanded in vitro, and passage 3 hESCs were induced by different concentrations of TGF-β1 (0.1, 5.0, and 10.0 ng/ml). Morphological fea-tures and identification of these cells were meseasured by HE, Masson, immunohistochemical staining on the days 3 and 7, respectively. Results After induced by TGF-β1 for 3 and 7 days, the morpholo-gy of the epidermal stem cell (hESCs) was changed into fusiform shape, similar to fibroblasts. 70 % ofthe cell which was induced by TGF-β1 were blue stained in the cytoplasm by Masson stain, which is the distinctive method for collagen, suggesting collagen appeared or increased in the cells. The collagen concentrations in supernatants of hESCs were 0.4150±0.0014, 0.3380±0. 0020, and 0.3870±0.0020, much higher than that in control group (0.0780±0.0025) and normal skin fibro-blast group (0.15004±0.0051) (P<0.05). Immunohistochemical staining revealed that positive rates of these cells for anti-vimentin staining were more than (95.00±1.20)% in experiments and (5.70±0.20)% in control group. Conclusion The differentiantion of hESCs induced by TGF-β1 into fibro-blasts indicates that hESCs may play a role in the pathogenesis of hypetrophic scar and keloid.

Objective To investigate the inductive role of traumatic microenvironment in dedifferentiation of epidermal cells and explore the potential role of Wnt signaling pathway in this biological process. Methods The sheets of human foreskin were digested overnight after removal of adipose tissue, and then the epidermis was separated from the dermis. The separated epidermis sheets were repeatedly adhered to type Ⅳ collagen and flushed to remove the epidermal stem cells. The obtained epidermis sheets were transplanted onto the full-thickness skin wounds on the back of BALB/c nude mice, five days after which the cell lineage was evaluated by immunohistochemistry and the expressions of Wnts and downstream components in the grafted epidermal sheets examined by RT-PCR and Western blot. Results The cells in the basal layer of full-thickness epidermal sheets were positive for CK19 and β1 integrin and negative for CK10. While the cells in uhrathin epidermal sheets treated with type Ⅳ collagen were fully positive for CK10. Five days after transplantation of the ultrathin epidermal sheets, cells negative for CK10 but positive for CK19 and β1 integrin emerged at the wound-neighboring side of the skin grafts. At the same time, the expressions of Wnt-10b, Wnt-4 and Wnt-7a mRNA were increased by about 3.1-fold, 2.2-fold and 1.4-fold independently after transplantation. Furthermore, the expressions of β-catenin and β-catenin target genes (cyclin D1 and c-myc) were elevated by about 3-fold, 1.5-fold and 2-fold respectively in the grafted epidermal sheets (P < 0.01). Conclusion Traumatic microenvironment can induce epidermal cell dedifferentiation, when the Wnt/β -catenin signaling pathway may play an important role.

Objective To explore the effect of botulinum toxin type A(BTXA)in the treatment of early hypertrophic scars(HTS).Methods BTXA was injected into and around the eady HTS,and then the modal and histological changes of the scars as well as the clinical reaction were observed in the patient.BTXA was also injected into muscle around the incision and effect on the cicatrization observed.Results Injection of BTXA could obviously alleviate ache and pruritus of eady HTS and could impel the atrophy and inteneration of eady HTS.Changes were found in paraffin-embedded tissue section by the hemetoxylin and eosin(HE)staining.Injection of BTXA into muscle around the cut could can reduce occurrence of HTS.Conclusion BTXA can help prevent the early HTS to a certain extent.The mechanism underlying this effect may be related to the reducing the tension around scars and proliferative activity,interfering with the signal transduction of small nerves,affecting the proliferation and apoptosis of fibroblasts and subsequently decreasing the collagen synthesis.

Objective To investigate the possible signaling mechanisms by which recombinant human platelet-derived growth factor (rhPDGF) accelerated healing of cutaneous wound in diabetic rats. Methods Four full-thickness skin wounds were incised in the back of 26 male Wistar diabetic rats. The wounded rats were divided into 3 groups (7 or 8 rats each group). One group without treatment was used as a control, and the other 2 groups were treated with rhPDGF at a dose of 7.0 μg/cm2 wound or vehicle ( DMSO/0.9%NaCl, vol/vol 1:1) from 1 to 14 days. The wound healing was evaluated by the measurements of the wound volume and area. Immunofluorescent and immunohistochemical staining were used to examine the phosphorylation of extracellular signal-regulated kinase 1/2(ERK1/2) and the expression of proliferative cell nuclear antigen (PCNA), respectively. Results Granulation tissue appeared in the bed of wound after injury. The number of blood capillary buds and fibroblasts was greater in the rhPDGF-treated group than that in the other 2 groups. A lot of inflammatory cells infiltration and collagen deposition were observed in the wound. The wound-volume in the rhPDGF-treated group was smaller than that in control group ( P ＜ 0.05). The reepithelialization rate in rhPDGF-treated group was higher than that in the other 2 groups at 7 days after injury ( P ＜ 0.05). The expression of PCNA in reparative cells was higher in rhPDGF-treated group than in control group or vehicle-treated group at 3,7 days after injury( P ＜ 0.05). The phosphorylation of ERK1/2 was stronger in rhPDGF-treated group than that in control group or vehicle group at 7 and 14 days after injury( P ＜ 0.05). Conclusion These results suggest that rhPDGF accelerates wound healing and improves healing quality by increasing the phosphorylation of ERK1/2.

Objective To investigated the distribution of epidermal stem cells in rat full-thickness wound tissues during the wound healing process and to elucidate the roles of epidermal stem cells in wound repair in vivo. Methods Eighty circular full-thickness wounds were produced on both sides of the back in 20 male Wistar rats labeled with BrdU 60 days previously (4 wounds in each rat). BrdU, β1 integrin and keratin 19 (K19) were employed to determine the epidermal stem cells with SP immunohistochemical methods, and the epithelialization was determined with routine histological methods of HE staining on the 3rd, 7th, 14th, and 21st days after operation. Results No cells with positive immunostaining for β1 integrin, K19 and BrdU were found in granulation tissue of wound in both groups during the healing process. However, a few scattered β1 integrin and K19 positive cells were found within the stratum spinosum and stratum granulosum of the epidermis on the wound edges on the 3rd day post-injury. And these positive cells gradually became more and more in number, and mostly concentrated on the border of wound edges till the wounds healed. In addition, the number of positive cells for β1 integrin and K19 in the infected wounds was less than that in non-infected wounds. These positive cells for β1 integrin and K19 staining on the wound edge were also positively stained with BrdU in the cellular nuclei. Conclusion The above results indicate that ectopia of epidermal stem cells present a major function during wound epithelialization.