BACKGROUND: Glucocorticoids have been widely used to treat patients with chronic obstructive pulmonary disease (COPD). Nevertheless, corticosteroid insensitivity is a major barrier to the effective treatment of COPD and its mechanism remains unclear. This study aimed to evaluate the effect of cathelicidin LL-37 on corticosteroid insensitivity in COPD rat model, and to explore the involved mechanisms. METHODS: COPD model was established by exposing male Wistar rats to cigarette smoke combined with intratracheal instillation of lipopolysaccharide (LPS). Inhaled budesonide and LL-37 were consequently applied to COPD models separately or collectively to confirm the effects on inflammatory cytokines (tumor necrosis factor [TNF]-α and transforming growth factor [TGF]-β) by enzyme-linked immunosorbent assay (ELISA) and lung tissue histopathological morphology. Expression of histone deacetylase-2 (HDAC2) and phosphorylation of Akt (p-AKT) in lung were also measured. RESULTS: Briefly, COPD model rats showed an increased basal release of inflammatory cytokines (lung TNF-α: 45.7 ± 6.1 vs. 20.1 ± 3.8 pg/mL, P < 0.01; serum TNF-α: 8.9 ± 1.2 vs. 6.7 ± 0.5 pg/mL, P = 0.01; lung TGF-β: 122.4 ± 20.8 vs. 81.9 ± 10.8 pg/mL, P < 0.01; serum TGF-β: 38.9 ± 8.5 vs. 20.6 ± 2.3 pg/mL, P < 0.01) and COPD related lung tissue histopathological changes, as well as corticosteroid resistance molecular profile characterized by an increase in phosphoinositide 3-kinase (PI3K)/Akt (0.5 ± 0.1 fold of control vs. 0.2 ± 0.1 fold of control, P = 0.04) and a decrease in HDAC2 expression and activity (expression: 13.1 ± 0.4 μmol/μg vs. 17.4 ± 1.1 μmol/μg, P < 0.01; activity: 1.1 ± 0.1 unit vs. 1.4 ± 0.1 unit, P < 0.01), compared with control group. In addition, LL-37 enhanced the anti-inflammatory effect of budesonide in an additive manner. Treatment with combination of inhaled corticosteroids (ICS) and LL-37 led to a significant increase of HDAC2 expression and activity (expression: 15.7 ± 0.4 μmol/μg vs. 14.1 ± 0.9 μmol/μg, P < 0.01; activity: 1.3 ± 0.1 unit vs. 1.0 ± 0.1 unit, P < 0.01), along with decrease of p-AKT compared to budesonide monotherapy (0.1 ± 0.0 fold of control vs. 0.3 ± 0.1 fold of control, P < 0.01). CONCLUSIONS This study suggested that LL-37 could improve the anti-inflammatory activity of budesonide in cigarette smoke and LPS-induced COPD rat model by enhancing the expression and activity of HDAC2. The mechanism of this function of LL-37 might involve the inhibition of PI3K/Akt pathway.
Animals ; Antimicrobial Cationic Peptides ; pharmacology ; therapeutic use ; Glucocorticoids ; metabolism ; Histone Deacetylase 2 ; metabolism ; Humans ; Inflammation ; chemically induced ; drug therapy ; Lipopolysaccharides ; pharmacology ; Male ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Pulmonary Disease, Chronic Obstructive ; drug therapy ; metabolism ; Rats ; Rats, Wistar ; Smoking ; adverse effects ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVE: To discuss the clinical significance of antibacterial peptide LL-37 in the early diagnosis of patients with sepsis in emergency department. METHODS: Forty patients diagnosed with sepsis in the emergency department of the Affiliated Hospital of Zunyi Medical College from December 2017 to March 2018 were enrolled as sepsis group. Twenty healthy volunteers were enrolled contemporaneously in our hospital at medical center as healthy control group. Peripheral blood was collected immediately after diagnosis in sepsis group or during physical examination in healthy control group. The expression of antibacterial peptide LL-37 was determined by enzyme-linked immunosorbent assay (ELISA). Meanwhile, serum procalcitonin (PCT) and C-reactive protein (CRP) levels were determined. The differences in antibacterial peptide LL-37, PCT and CRP levels between the two groups were compared. Pearson correlation method was used to analyze the correlation between antibacterial peptide LL-37, PCT and CRP. Receiver operating characteristic (ROC) curve was drawn, and the early individually or jointly diagnostic value of each detected index for sepsis was analyzed. RESULTS: The levels of antimicrobial peptide LL-37, PCT and CRP in peripheral blood of sepsis group were significantly higher than those of healthy control group [LL-37 (μg/L): 1.34±0.69 vs. 0.10±0.06, PCT (μg/L): 46.67±39.51 vs. 0.03±0.02, CRP (mg/L): 129.68±49.83 vs. 3.16±2.85], with statistically significant differences (all P < 0.05). Pearson correlation analysis showed that the expression of antimicrobial peptide LL-37 was positively correlated with PCT and CRP levels (r₁ = 0.835, r₂ = 0.932, both P < 0.01). ROC curve analysis showed that the area under ROC curve (AUC) of LL-37, PCT and CRP for early diagnosis of sepsis was 0.885, 0.963 and 0.983, respectively, and the AUC of combined diagnosis of the three parameters was as high as 0.994, indicating that the value of combined diagnosis of sepsis was greater than that of single diagnosis; when the combined prediction probability of the three parameters was 0.92, the sensitivity was 97.5%, and the specificity was 95.0%. CONCLUSIONS Antibacterial peptide LL-37 has certain clinical value in early diagnosis of patients with sepsis, which can be used as early routine monitoring indicators for patients with early sepsis when combined with PCT and CRP.
Antimicrobial Cationic Peptides/metabolism* ; C-Reactive Protein ; Calcitonin ; Calcitonin Gene-Related Peptide ; Early Diagnosis ; Emergency Service, Hospital ; Humans ; Protein Precursors ; ROC Curve ; Sepsis/metabolism* ; Cathelicidins

OBJECTIVE: To evaluate the application of heparin-binding protein (HBP) in diagnosis of sepsis in adult patients. METHODS: An extensive search for the Chinese and English literatures from the PubMed, Embase, the Cochrane Library, Wanfang data, CNKI and VIP up to July 2019 was performed. The articles regarding HBP for the diagnosing of sepsis in adult patients were enrolled. Two researchers independently extracted related literature. The quality of the studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-Disc 1.4 and STATA 12.0 were used for Meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated. Summary receiver operating characteristic (SROC) curves and area under the curve (AUC) were used to evaluate the diagnostic performance of HBP for sepsis. Deek funnel plot was used to detect publication bias. RESULTS: A total of 10 studies with 1 884 patients were included in this Meta-analysis. The quality of the literature was relatively moderate. HBP in plasma were detected by enzyme linked immunosorbent assay (ELISA) in all studies. The studies showed substantial heterogeneity, and random effect model was used for Meta-analysis. The pooled sensitivity, specificity, PLR, NLR, and DOR were 0.80 [95% confidence interval (95%CI) was 0.77-0.83], 0.80 (95%CI was 0.78-0.82), 3.96 (95%CI was 2.45-6.41), 0.28 (95%CI was 0.20-0.39) and 14.63 (95%CI was 6.83-31.30) respectively. The pooled AUC was 0.86 and the Cochran-Q was 0.79. To explore the potential sources of heterogeneity, subgroup analyses were performed based on the severity of the disease, diagnostic criteria and region. However, the results indicated that no methodological covariates affected the diagnostic accuracy of HBP, indicating that there was still unexplained heterogeneity. In addition, the sensitivity analysis by removing individual studies were performed. No outlier study was identified and the results were relatively stable and reliable. Deek funnel plot showed little publication bias. CONCLUSIONS There is preferable value of HBP for diagnosis of sepsis in adult patients. However, it needs to be further confirmed by large multicenter studies.
Adult ; Antimicrobial Cationic Peptides/metabolism* ; Blood Proteins/metabolism* ; Humans ; Sensitivity and Specificity ; Sepsis/metabolism*

BACKGROUNDAntimicrobial peptides, including cathelicidin LL-37, human beta defensin (HBD)-2, and HBD-3, are important elements of the innate immune response and involved in modulation of the adaptive immunity, and they also play an important role in cutaneous defense against Mycobacterium tuberculosis.

METHODSThe fresh skin tissues and paraffin-embedded biopsy samples from three cutaneous tuberculosis, two tuberculids, and ten healthy individuals were collected. The expressions of LL-37, HBD-2, and HBD-3 mRNA in the lesions of three cutaneous tuberculosis and two tuberculids were detected by quantitative real-time polymerase chain reaction; the protein expressions were detected by immunohistochemistry and Western blotting methods.

RESULTSThe expressions of LL-37 mRNA and protein in the lesions of cutaneous tuberculosis and tuberculids were similar to that of normal skin. The expression of HBD-2 mRNA had an increasing trend in the lesions of cutaneous tuberculosis and tuberculids compared with that of normal skin; however, the expression of HBD-2 protein in the lesions of cutaneous tuberculosis had a decreasing trend compared with that of normal skin, and the expression of HBD-2 protein in the lesions of tuberculids was similar to that of normal skin. The expressions of HBD-3 mRNA and protein in lesions of cutaneous tuberculosis and tuberculids were similar to that of normal skin.

CONCLUSIONSOur study indicated that the expression of HBD-2 and HBD-3 mRNA and protein in lesions of cutaneous tuberculosis may be not consistent with that of tuberculids. However, an inherent limitation of the present study was that the sample size was small, and the roles and regulation mechanisms of LL-37, HBD-2, and HBD-3 in cutaneous tuberculosis and tuberculids need to be further investigated.

Adult ; Aged ; Antimicrobial Cationic Peptides ; genetics ; Female ; Humans ; Male ; Middle Aged ; RNA, Messenger ; analysis ; Tuberculosis, Cutaneous ; metabolism ; beta-Defensins ; genetics

OBJECTIVETo investigate the effect of antibacterial peptide hCAP18/LL-37 on ovarian cancer microenvironment and the regulatory mechanism of its expression.

METHODSWe assessed the effect of macrophage-promoted ovarian cancer cells invasion using BioCoat Matrigel invasion chamber. The expressions of hCAP18/LL-37 and versican V1 were determined by real-time PCR and Western blot analysis. SKOV3 cells were transfected with shRNA plasmid to abrogate the expression of versican V1, and then the expression of hCAP18/LL-37 in macrophages and the invasiveness of SKOV3 cells were assayed.

RESULTSThe Matrigel invasion assay showed that after co-culture with macrophages for 4 days, the number of penetrated SKOV3 cells was 112.8±17.1/per high power field, significantly higher than that in the SKOV3 cells cultured alone (8.2±1.9/per high power field) (P<0.05). Addition of hCAP/LL-37 neutralizing antibody into the co-cultured macrophage-SKOV3 cells markedly inhibited the macrophage-promoted SKOV3 cells invasion. The penetrated SKOV3 cells was 22.2±5.6/per high power field, significantly lower than the 100.6±25.2/per high power field in the control macrophage- SKOV3 co-cultured cells (P<0.05). The expressions of hCAP18/LL-37 mRNA and protein in macrophages were remarkably enhanced upon co-culture with SKOV3 cells, but not changed in SKOV3 cells cultured alone. The expression and secretion of versican V1 in the ovarian cancer cells were also significantly increased after co-cultured with macrophages. Knockdown of versican V1 in SKOV3 cells by small interfering RNA significantly reduced the expression of hCAP18/LL-37 mRNA and protein in the macrophages, as well as decreased the invasiveness of SKOV3 cells (P<0.05).

CONCLUSIONSIn the cancer microenvironment, the macrophage-secreted hCAP18/LL-37 promote the invasiveness of ovarian cancer cells, and the hCAP18/LL-37 expression is regulated by versican V1 protein released by ovarian cancer cells.

Antimicrobial Cationic Peptides ; metabolism ; pharmacology ; Cell Line, Tumor ; Coculture Techniques ; Collagen ; Drug Combinations ; Female ; Humans ; Laminin ; Macrophages ; metabolism ; Neoplasm Invasiveness ; Neoplasm Proteins ; metabolism ; Ovarian Neoplasms ; metabolism ; pathology ; physiopathology ; Plasmids ; Proteoglycans ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; Real-Time Polymerase Chain Reaction ; Transfection ; Tumor Microenvironment ; drug effects ; Versicans ; metabolism

AIK is a novel cationic peptide with potential antitumor activity. In order to construct the AIK expression vector by Gateway technology, and establish an optimal expression and purification method for recombinant AIK, a set of primers containing AttB sites were designed and used to create the AttB-TEV-FLAG-AIR fusion gene by overlapping PCR. The resulting fusion gene was cloned into the donor vector pDONR223 by attB and attP mediated recombination (BP reaction), then, transferred into the destination vector pDESTl 5 by attL and attR mediated recombination (LR reaction). All the cloning was verified by both colony PCR and DNA sequencing. The BL21 F. coli transformed by the GST-AIR expression plasmid was used to express the GST-AIK fusion protein with IPTG induction and the induction conditions were optimized. GST-AIR fusion protein was purified by glutathione magnetic beads, followed by rTEV cleavage to remove GST tag and MTS assay to test the growth inhibition activity of the recombinant AIR on human leukemia HL-60 cells. We found that a high level of soluble expression of GST-AIK protein (more than 30% out of the total bacterial proteins) was achieved upon 0.1 mmol/L ITPG induction for 4 h at 37 °C in the transformed BL21 F. coli with starting OD₆₀₀ at 1.0. Through GST affinity purification and rTEV cleavage, the purity of the resulting recombinant AIK was greater than 95%. And the MTS assays on HL-60 cells confirmed that the recombinant AIK retains an antitumor activity at a level similar to the chemically synthesized AIK. Taken together, we have established a method for expression and purification of recombinant AIK with a potent activity against tumor cells, which will be beneficial for the large-scale production and application of recombinant AIK in the future.
Antimicrobial Cationic Peptides ; biosynthesis ; Antineoplastic Agents ; metabolism ; Escherichia coli ; metabolism ; Genetic Vectors ; HL-60 Cells ; Humans ; Polymerase Chain Reaction ; Recombinant Proteins ; biosynthesis ; Sequence Analysis, DNA

BACKGROUNDAdenoid hypertrophy (AH) is associated with pediatric chronic rhinosinusitis (pCRS), but its role in the inflammatory process of pCRS is unclear. It is thought that innate immunity gene expression is disrupted in the epithelium of patients with chronic rhinosinusitis (CRS), including antimicrobial peptides and pattern recognition receptors (PRRs). The aim of this preliminary study was to detect the expression of innate immunity genes in epithelial cells of hypertrophic adenoids with and without pCRS to better understand their role in pCRS.

METHODSNine pCRS patients and nine simple AH patients undergoing adenoidectomy were recruited for the study. Adenoidal epithelium was isolated, and real-time quantitative polymerase chain reaction (RT-qPCR) was employed to measure relative expression levels of the following messenger RNAs in hypertrophic adenoid epithelial cells of pediatric patients with and without CRS: Human β-defensin (HBD) 2 and 3, surfactant protein (SP)-A and D, toll-like receptors 1-10, nucleotide-binding oligomerization domain (NOD)-like receptors NOD 1, NOD 2, and NACHT, LRR and PYD domains-containing protein 3, retinoic acid-induced gene 1, melanoma differentiation-associated gene 5, and nuclear factor-κB (NF-κB). RT-qPCR data from two groups were analyzed by independent sample t-tests and Mann-Whitney U-tests.

RESULTSThe relative expression of SP-D in adenoidal epithelium of pCRS group was significantly lower than that in AH group (pCRS 0.73 ± 0.10 vs. AH 1.21 ± 0.15; P = 0.0173, t = 2.654). The relative expression levels of all tested PRRs and NF-κB, as well as HBD-2, HBD-3, and SP-A, showed no statistically significant differences in isolated adenoidal epithelium between pCRS group and AH group.

CONCLUSIONSDown-regulated SP-D levels in adenoidal epithelium may contribute to the development of pCRS. PRRs, however, are unlikely to play a significant role in the inflammatory process of pCRS.

Adenoids ; cytology ; Antimicrobial Cationic Peptides ; metabolism ; Child ; Epithelial Cells ; metabolism ; Female ; Humans ; Immunity, Innate ; genetics ; physiology ; Male ; Receptors, Pattern Recognition ; metabolism ; Sinusitis ; metabolism ; Toll-Like Receptors ; metabolism

Due to their potential application as novel antibiotics, antimicrobial peptides are attracting much attention. Large quantities of highly purified peptides are crucial to basic and clinical studies. Natural resources of antimicrobial peptides are limited and hard to purify, chemical synthesis is of high-cost and unstable, so recombinant expression of antimicrobial peptides is a cost-effective way. Escherichia coli has been the most widely used as host to express antimicrobial peptides with fusion protein, which can not only avoid the lethal effect towards the host, but also protect the peptide from degradation by proteases. Combined with our research, the present article reviews the progress of fusion vector, cleavage methods and optimization options for antimicrobial peptides production with fusion protein in Escherichia coli.
Antimicrobial Cationic Peptides ; biosynthesis ; Escherichia coli ; metabolism ; Genetic Vectors ; Recombinant Fusion Proteins ; biosynthesis

PURPOSE: Recent findings of increased cathelicidin protein and its proteolytic fragments in rosacea suggest a pathogenic role for cathelicidin in this disease. The relationship between cathelicidin and protease-activated receptor 2 (PAR-2) is therefore of interest, as PAR-2, expressed principally in keratinocytes, regulates pro-inflammatory cytokine expression in the skin. The purpose of this study was to determine the relationship between expression of PAR-2 and cathelicidin in rosacea and to test the effect of direct PAR-2 activation on cathelicidin expression in keratinocytes. MATERIALS AND METHODS: Samples from 40 patients with clinicopathologic diagnosis of rosacea and facial skin tissue samples from 20 patients with no specific findings or milium without inflammation were retrieved. Intensities of immunohistochemical staining for PAR-2 and cathelicidin were compared between normal and rosacea-affected skin tissues. Additionally, correlations between PAR-2 and cathelicidin staining intensities within rosacea patients were analyzed. In cultured keratinocytes, changes in PAR-2, cathelicidin, and vascular endothelial growth factor (VEGF) mRNA and protein were analyzed after treatment with PAR-2 activating peptide (AP). RESULTS: Cathelicidin expression was significantly higher in rosacea skin tissues than in normal tissues (p<0.001), while PAR-2 expression was not significantly higher in rosacea tissues than in normal skin tissues. A positive correlation between PAR-2 and cathelicidin within rosacea samples was observed (R=0.330, p=0.037). After treatment of PAR-2 AP, both mRNA and protein levels for PAR-2, cathelicidin, and VEGF significantly increased in cultured keratinocytes, compared with PAR-2 control peptide treatment. CONCLUSION: PAR-2 may participate in the pathogenesis of rosacea through activation of cathelicidin LL-37, a mediator of innate immune responses in the skin.
Adult ; Aged ; Antimicrobial Cationic Peptides/*metabolism ; Cytokines/metabolism ; Female ; Humans ; Immunity, Innate ; Inflammation/metabolism ; Keratinocytes/*metabolism ; Male ; Middle Aged ; Receptor, PAR-2/*metabolism ; Rosacea/*pathology ; Skin/pathology ; Vascular Endothelial Growth Factor A/*metabolism

Penaeidin-2 (Pen-2) is an important antimicrobial peptide derived from the Pacific white shrimp, Penaeus vannamei, and possesses both antibacterial and antifungal activities. Recent studies suggest that recombinant penaeidins show similar activities to the native Pen-2 protein. Previous researches have shown that some antimicrobial peptides (AMPs) exhibit cytotoxic activity against cancer cells. To date, there have been no studies on the antitumor effects of Pen-2. This study evaluated the potential of recombinant pen-2 (rPen-2) in the selective killing of kidney cancer cell lines ACHN and A498, and its action mechanism. MTT assays found the maximal growth inhibition of HK-2, ACHN and A498 cells treated with 100 μg/mL rPen-2 at 48 h was 13.2%, 62.4%, and 70.4%, respectively. DNA-specific fluorescent dye staining showed a high percentage of apoptosis on cancer cells. Flow cytometry revealed that the apoptosis rate of HK-2, ACHN and A498 cells was 15.2%, 55.2%, and 61.5% at 48 h respectively, suggesting that rPen-2 induced higher apoptosis rate in cancer cells than in HK-2 cells. Laser confocal scanning microscopy demonstrated that the plasma membrane was the key site where rPen-2 interacted with and destroyed tumor cells. Scanning electron microscopy showed the morphologic changes of the cell membranes of kidney cancer cells treated with rPen-2. These results suggest that rPen-2 is a novel potential therapeutic agent that may be useful in treating kidney cancers.
Animals ; Antimicrobial Cationic Peptides ; genetics ; pharmacology ; Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Arthropod Proteins ; genetics ; pharmacology ; Drug Screening Assays, Antitumor ; Humans ; Kidney Neoplasms ; drug therapy ; metabolism ; pathology ; Penaeidae ; genetics ; Recombinant Proteins ; genetics ; pharmacology