Humanized Mice as Preclinical Models in Transplantation

Animal models have been instrumental in our understanding of the mechanisms of rejection and the testing of novel treatment options in the context of transplantation. We have now entered an exciting era with research on humanized mice driving advances in translational studies and in our understanding of the function of human cells in response to pathogens and cancer as well as the recognition of human allogeneic tissues in vivo. In this chapter we provide a historical overview of humanized mouse models of transplantation to date, outlining the distinct strains and share our experiences in the study of human transplantation immunology.

The peroxisome proliferator-activated receptor γ agonist pioglitazone prevents NF-κB activation in cisplatin nephrotoxicity through the reduction of p65 acetylation via the AMPK-SIRT1/p300 pathway

The thiazolidinedione pioglitazone, which is also a PPAR-γ agonist, now is widely used in patients with hypercholesterolemia and hypertriglyceridemia. NF-κB is a ubiquitously expressed transcription factor controlling the expression of numerous genes involved in inflammation. The aim of the present study was to evaluate whether the activation of PPAR-γ attenuates the cisplatin-induced NF-κB activation in cisplatin nephrotoxicity. The results showed that the PPAR-γ agonist pioglitazone decreased the expression of NF-κB p65 transcription target genes (e.g., IL-6, IL-1β, and TNF-α) and inhibited histological injury and inflammatory cells infiltration in cisplatin nephrotoxicity. The suppression of NF-κB activity following pioglitazone treatment inhibited the cisplatin-induced IκB-α degredation and NF-κB p65 subunit translocation. Translocation of the NF-κB p65 subunit depends on p65 acetylation, which primarily regulated by SIRT1 or p300. Notably, AMP kinase (AMPK) activation not only decreased the phosphorylation, activation and p65 interaction of p300 but also increased SIRT1 expression, activation and p65 binding, thus leading to a significant reduction in p65 acetylation. Interestingly, the reduction of IL-6, TNF-α and IL-1β, the inhibition of histological injury and the inflammatory cells infiltration following pioglitazone treatment in cisplatin nephrotoxicity were attenuated after treatment with the PPAR-γ antagonist GW9662. These results suggest that the PPAR-γ agonist pioglitazone prevents NF-κB activation in cisplatin nephrotoxicity through a reduction in p65 acetylation via the AMPK-SIRT1/p300 pathway.

Expressions of Senescence-Associated β-Galactosidase and Senescence Marker Protein-30 are Associated with Lens Epithelial Cell Apoptosis

BACKGROUND To investigate associations of senescence marker protein-30 and senescence-associated β-galactosidase expression with lens epithelial cells apoptosis among Chinese age-related cataract patients. MATERIAL AND METHODS A total of 145 age-related cataract patients (69 cases with nuclear cataract in 91 eyes and 76 cases of cortical cataract with 102 eyes) were enrolled in our study. An annular tear of the central part of anterior lens capsules was performed for each patient. Immunohistochemical staining and real-time PCR were used to detect the protein and mRNA expression levels, and TUNEL was used to assess lens epithelial cells apoptosis. Comparisons of protein expression levels and lens epithelial cells apoptosis were made between the 2 groups. RESULTS The results showed a higher protein expression level of senescence marker protein-30 in surrounding parts of the anterior lens capsule compared with the central part of the anterior lens capsule; however, the positive rate of senescence-associated β-galactosidase was remarkably higher in the central part than in the surrounding part. Compared with cortical cataract patients, nuclear cataract patients had elevated senescence marker protein-30 protein and mRNA expression levels, but had a decreased positive rate of senescence-associated β-galactosidase. TUNEL results showed that the lens epithelial cell apoptosis rate was higher in the central part of the anterior lens capsule than in the surrounding part in both groups. Within either central or surrounding area of anterior lens capsule, cortical cataract patients exhibited a significantly higher lens epithelial cell apoptosis rate in contrast with nuclear cataract patients. CONCLUSIONS Our study results suggest that senescence marker protein-30 and senescence-associated β-galactosidase expressions in both nuclear cataract and cortical cataract patients were associated with lens epithelial cells apoptosis.

Low expression of circulating microRNA-328 is associated with poor prognosis in patients with acute myeloid leukemia

BACKGROUND

Dysregulation of circulating miR-328 has been identified in several tumors and is associated with prognosis of patients. However, the expression pattern of miR-328 and the impact on prognosis has not yet been studied in acute myeloid leukemia (AML). The purpose of this study is to investigate the expression status of miR-328 and its clinical significance in AML patients.

METHODS

RNA was extracted from plasma of 176 patients with newly diagnosed AML and 70 healthy volunteers. The miR-328 expression was examined by Realtime quantitative PCR. The association of circulating miR-328 expression with clinicopathological factors and prognosis of AML patients was statistically analyzed.

RESULTS

The expression of miR-328 was significantly downregulated in AML patients (median value 22.99, range: 3.63-242.0) compared with those of healthy controls (median value 89.17, range: 12.05-397.7; P < 0.001), and miR-328 expression was markedly increased in patients after treatment than before (23.40 ± 1.76 vs. 46.61 ± 3.83, P < 0.001). Moreover, low levels of miR-328 were associated with a higher white blood cell count and BM blast count (P = 0.026 and P = 0.003, respectively), and lower hemoglobin and platelet count (P = 0.004 and P = 0.022, respectively). Patients with low miR-328 expression had a relatively poor overall survival (P = 0.022) and shorter relapse-free survival (P = 0.008) than those with high miR-328 expression. In addition, low miR-328 expression was an independent prognostic factors for both OS (P = 0.017) and RFS (P = 0.023).

CONCLUSIONS

Circulating miR-328 downregulation is a common event and is associated with poor clinical outcome in AML patients.

Clinical Safety and Preliminary Efficacy of Plasmid pUDK-HGF Expressing Human Hepatocyte Growth Factor (HGF) in Patients with Critical Limb Ischemia

OBJECTIVE

Critical limb ischemia (CLI) is the most severe form of peripheral arterial disease and a major unmet public health care need. This phase I clinical study was performed to assess the safety and preliminary efficacy of naked plasmid DNA (pUDK-HGF) expressing human hepatocyte growth factor (HGF) in patients with critical limb ischemia (CLI).

DESIGN

Twenty-one patients with CLI were enrolled and randomly divided into four dose groups (4-16 mg) to receive local injection of pUDK-HGF into ischemic calf and/or thigh muscles twice on days 1 and 15. Safety, including adverse events and physiological parameters, and preliminary efficacy, including pain severity score (VAS), ulcer size, transcutaneous oxygen pressure (TcPO2), and ankle brachial index (ABI), were evaluated throughout a 3 month follow up period.

RESULTS

All doses of pUDK-HGF were well tolerated by the patients. None of the adverse effects was considered to be related to pUDK-HGF injection. Two significant clinical results were observed after pUDK-HGF administration. The mean VAS value of all patients decreased from 4.52 at baseline to 0.30 (p < .01), and pain had disappeared in 14 out of 17 evaluable patients by day 91. Two of four ulcers had completely healed, with the other two patients having more than 25% ulcer size reduction in the long axis diameter. Of five patients with gangrene, one gangrenous wound had healed completely and two patients showed marked size reduction by day 91. The mean hemodynamic parameters (ABI, TcPO2) were also improved.

CONCLUSION

Intramuscular injection of pUDK-HGF is safe, and may provide symptomatic relief for CLI patients. A larger, randomized, double blinded phase II trial will provide more information on safety and efficacy.

[The neuroimaging features of Parkinson's disease and dystonia by transcranial sonography]

OBJECTIVE

To assess the neuroimaging features of Parkinson's Disease and dystonia by transcranial sonography (TCS).

METHODS

63 Parkinson's Disease patients, 32 dystonia patients and 81 controls underwent TCS in blind manner. The echo of the substantia nigra (SN) was classified into I-V as half quantitative data. The echo of SN≥III was considered to be positively enhanced, the hyperechogenicity were measured and the hyper-substantia nigra/midbrain (S/M) were calculated. The echo of the lentiform nucleus (LN) was classified into I-III as half quantitative data. The echo of LN≥II was considered to be positively increased and were measured.

RESULT

Semi-quantitative analysis: the ratio of the patients with SN≥III was greater in Parkinson's Disease patients (60.32%, 38/63) than in dystonia patients (12.50%, 4/32) and normal controls (11.11%, 8/72, χ2=19.67, 36.22, P<0.01, respectively), the ratio of the patients with LN≥II was greater in dystonia patients (65.62%, 21/32) than in Parkinson's Disease patients (20.63%, 13/63) and in controls (8.33%, 6/72, χ2=18.69, 37.83, P<0.01, respectively). Quantitative analysis:the median and quartile (M/Q) of the SN hyperechogenieity area in Parkinson's Disease patients [0.73 (0.53) cm2] was greater than in dystonia patients [0.56 (0.53) cm2] and in controls [0.44 (0.19) cm2, H=10.05, P=0.007], the S/M in Parkinson's Disease patients was greater [15.7% (11.5%)] than in dystonia patients [(13.8% (14.2%)] and in controls [8.9% (2.9%), H=6.96, P=0.031]. The M/Q of LN hyperechogenieity area in dystonia patients was greater [0.50 (0.33) cm2] than in Parkinson's Disease patients [0.45 (0.22) cm2] and in controls [0.35 (0.17) cm2, H=10.87, P=0.004].

CONCLUSION

TCS might find the specific hyperechogenicity of SN in Parkinson's Disease patients (60.32%) and hyperechogenicity of LN in dystonia patients (65.63%), which could provide useful informations to distinguish Parkinson's Disease from dystonia.

Targeted Blockade of JAK/STAT3 Signaling Inhibits Ovarian Carcinoma Growth

Ovarian carcinoma is the fifth leading cause of death among women in the United States. Persistent activation of STAT3 is frequently detected in ovarian carcinoma. STAT3 is activated by Janus family kinases (JAK) via cytokine receptors, growth factor receptor, and non-growth factor receptor tyrosine kinases. Activation of STAT3 mediates tumor cell proliferation, survival, motility, invasion, and angiogenesis, and recent work demonstrates that STAT3 activation suppresses antitumor immune responses and supports tumor-promoting inflammation. We hypothesized that therapeutic targeting of the JAK/STAT3 pathway would inhibit tumor growth by direct effects on ovarian carcinoma cells and by inhibition of cells in the tumor microenvironment (TME). To test this, we evaluated the effects of a small-molecule JAK inhibitor, AZD1480, on cell viability, apoptosis, proliferation, migration, and adhesion of ovarian carcinoma cells in vitro. We then evaluated the effects of AZD1480 on in vivo tumor growth and progression, gene expression, tumor-associated matrix metalloproteinase (MMP) activity, and immune cell populations in a transgenic mouse model of ovarian carcinoma. AZD1480 treatment inhibited STAT3 phosphorylation and DNA binding, and migration and adhesion of cultured ovarian carcinoma cells and ovarian tumor growth rate, volume, and ascites production in mice. In addition, drug treatment led to altered gene expression, decreased tumor-associated MMP activity, and fewer suppressor T cells in the peritoneal TME of tumor-bearing mice than control mice. Taken together, our results show pharmacologic inhibition of the JAK2/STAT3 pathway leads to disruption of functions essential for ovarian tumor growth and progression and represents a promising therapeutic strategy.

Association between loop diuretic use and fracture risk

SUMMARY

Loop diuretic use has been shown to be associated with an increased fracture risk, but the findings have been inconsistent. The present meta-analysis suggests that loop diuretics show a significant positive association with the overall risk of total fractures and, specifically, hip fractures.

INTRODUCTION

Despite being widely used, there is limited, prospective randomized trial evidence regarding the skeletal effects of loop diuretics. Previous observational studies have reported conflicting findings regarding the association between loop diuretic use and the risk of fractures.

METHODS

This meta-analysis of observational studies assessed the association between loop diuretic use and the risk of fractures. The PubMed, EMBASE, and OVID databases were searched for prospective cohort and case-control studies. Relative risks (RR) with 95% confidence intervals (CI) were derived using random-effects models throughout the analysis.

RESULTS

Thirteen studies (4 cohort studies and 9 case-control studies) were included, involving 842,644 participants and 108,247 fracture cases. Compared with non-users, people who had taken loop diuretics had an approximately 15% higher risk of total fractures (95% CI, 1.04-1.26; p<0.01), with high heterogeneity between studies (I2=80.5%; p<0.01). The RR was 1.14 (95% CI, 1.08-1.19) for hip fractures and 0.99 (95% CI, 0.93-1.05) for lower arm or wrist fractures. The RR was 1.05 (95% CI, 1.00-1.11) in prospective cohort studies and 1.22 (95% CI, 1.00-1.44) in case-control studies. There was no evidence of publication bias.

CONCLUSION

The results suggest that loop diuretics show a significant positive association with the overall risk of total fractures and hip fractures.

Removal of emerging contaminants by pre-mixed PACl and carbonaceous materials

In this study, pre-mixed poly aluminum chloride (PACl) and super powdered activated carbon (SPAC)/carbon nanotubes (CNT) were employed for the removal of emerging contaminants (ECs) from various water sources.

Correction: Removal of emerging contaminants by pre-mixed PACl and carbonaceous materials

Correction for ‘Removal of emerging contaminants by pre-mixed PACl and carbonaceous materials’ by W. Jiang et al., RSC Adv., 2015, 5, 35461–35468.

Desipramine ameliorates Cr(VI)-induced hepatocellular apoptosis via the inhibition of ceramide channel formation and mitochondrial PTP opening

BACKGROUND

Hexavalent chromium (Cr(VI)) is a common environmental pollutant. Cr(VI) exposure can lead to severe damage in the liver, but the preventive measures to diminish Cr(VI)-induced hepatotoxicity need further study. Acid sphingomyelinase (ASMase) is responsible for the production of ceramide via the hydrolysis of sphingomyelin. The present study was designed to investigate effects of desipramine (DES), as an ASMase inhibitor, on Cr(VI)-induced hepatotoxicity.

METHODS

L-02 hepatocytes were incubated with different concentrations of Cr(VI) for 24h, and ASMase activities and ceramide levels were measured. Moreover, the study investigated the role of DES played in ASMase activities and ceramide levels. Finally, effects of DES on mRNA and protein expressions of the components of mitochondrial permeability transition pore (PTP) and PTP opening were detected.

RESULTS

The ASMase activities and ceramide contents increased in L-02 hepatocytes treated with Cr(VI). The results demonstrated that apoptosis rates, ASMase activities and ceramide content decreased in groups treated with the combination of DES and Cr(VI) compared to Cr(VI) groups. Furthermore, DES inhibited Cr(VI)-induced mitochondrial PTP opening by intervening the mRNA and protein expressions of the components of mitochondrial PTP.

CONCLUSIONS

DES may exert protective effects on Cr(VI)-induced hepatocellular apoptosis probably by inhibiting ceramide channel formation and mitochondrial PTP opening.

[Effects of 10% Liuyangmycin emulsifiable on mitochondrial function in L-02 hepatocytes]

OBJECTIVE

To investigate the effects of 10% Liuyangmycin emulsifiable (LY-EC) on mitochondrial function in L-02 hepatocytes.

METHODS

To detect the effect of different concentration of LY-EC (0 -200 mg/L) on L-02 hepatocytes survival rate with MTT method, and choose proper LY-EC treated concentrations (survival rate > 70%) for the following experiments. After hepatocytes were treated with LY-EC at 0.39, 1.56, 6.25 and 25.00 mg/L respectively for 12 h, MDA and GSH contents, SOD, SDH, ATPase activities were respectively analyzed by their assay kits using colorimetry. Then mitochondrial PTP open percentage and the contents of ATP, ADP and AMP were measured with HPLC assays, and ATP/ADP ratio and energy charge (EC) values were calculated. The effects of LY-EC on mitochondrial ultra-structures were observed by transmission electron microscopy.

RESULTS

LY-EC induced the decrease of cell survival rates in a concentrate- dependent manner (r = 0.939, P < 0.05). Compared with control group, GSH contents and SOD, SDH and ATPase activities in groups treated with LY-EC decreased significantly, MDA contents and mitochondrial PTP open percentages increased (P < 0.05), the levels of cellular ATP, TAN and ATP/ADP ratio in L-02 hepatocytes decreased, while energy charge (EC) increased significantly (P < 0.05). Hepatocytes treated with LY-EC were observed cytoplasmic edema, mitochondria swelling and the deformation of mitochondrial cristae with transmission electron microscope.

CONCLUSION

LY-EC induced oxidative stress, mitochondrial function damage and energy metabolism disorder in L-02 hepatocytes.

Abstract 3916: HSP90 mediates tumor-associated matrix metalloproteinase 2 and Cathepsin L protease activities in ovarian carcinoma

Ovarian cancer is the fifth leading cause of cancer-related deaths among women in the United States. At diagnosis, disease has commonly spread beyond the ovary. Ovarian cancer cells dislodge from primary tumor and spread locally throughout the abdominal cavity and lymphatics. Cancer cell shedding and colonization at other sites involves the degradation of extra cellular matrix (ECM) by tumor-associated proteases, such as matrix metalloproteinase (MMPs) and cathepsin proteases. Heat shock protein 90 (HSP90) is an ATP-dependent molecular chaperone that interacts with and stabilizes MMPs in some solid tumors. Whether HSP90 regulates cathepsin activity is currently unknown. To determine the role of HSP90 on tumor-associated MMP and cathepsin protease activities in ovarian carcinoma, HSP90 activity was inhibited using pharmacologic and RNA interference (RNAi) approaches. A small molecule inhibitor, ganetespib, and two HSP90 targeting siRNAs were used to determine the effects of HSP90 inhibition on ovarian carcinoma cell line invasion using transwell and spheroid invasion assays. The effects of ganetespib or HSP90 targeting siRNA treatment on MMP and cathepsin protease activities were assayed by gelatin zymography (MMPs), enzyme assay (cathepsins) and by dynamic imaging using protease cleavable imaging probes. The effects of ganetespib treatment on in vivo orthotopic tumor growth, dissemination and tumor associated protease activities were determined using human ovarian carcinoma xenograft models. In vitro, ganetespib treatment or expression of HSP90-targeted siRNAs inhibited transwell and spheroid invasion, and MMP-2 and cathepsin L protease activities. In vivo, ganetespib treatment resulted in decreased growth of primary tumors and disseminated tumor nodules and decreased tumor-associated MMP and cathepsin activities. Importantly, significant inhibition of MMP and cathepsin activities was detected prior to differences in tumor volume, demonstrating rapid functional response to the drug. These results show that HSP90 regulates ovarian carcinoma-associated proteolytic activities that are essential to tumor progression and dissemination. They also point to the potential utility of HSP90 inhibition as a therapeutic strategy for the treatment of ovarian cancer.

Citation Format: Shane W. O'Brien, Fang Xiao, Marsia A. Maglaty, Joshua S. Trinadad, Lainie P. Martin, David A. Proia, Denise C. Connolly. HSP90 mediates tumor-associated matrix metalloproteinase 2 and Cathepsin L protease activities in ovarian carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3916. doi:10.1158/1538-7445.AM2014-3916

Abstract 1113: Targeting the JAK2/STAT3 pathway in ovarian cancer

Ovarian cancer is the fifth leading cause of death and the most lethal gynecological cancer among women in the United States. Persistent activation of signal transducer and activator of transcription 3 (STAT3), a cytoplasmic transcription factor, is frequently detected in EOC. STAT3 transduces signals from cytokines such as interleukin 6 (IL-6) via interactions with the IL-6 receptor and Janus kinases (JAK). JAK2 activates STAT3 by phosphorylation, leading to dimerization and translocation of STAT3 to the nucleus where it activates transcription of target genes regulating proliferation, survival and motility. Importantly, in addition to tumor cells, STAT3 signaling is also critical for immune cell activity and, in particular, inflammatory response. The inflammatory tumor microenvironment is important for ovarian cancer progression; therefore, we hypothesized that disruption of the STAT3 pathway would block ovarian tumor progression by: 1) directly inhibiting the growth of tumor cells; and 2) reducing a pro-tumorigenic inflammatory microenvironment. To target JAK2-mediated activation of STAT3 we used AZD1480, a JAK2-selective small molecule inhibitor. The effects of AZD1480 treatment on cell proliferation, apoptosis, adhesion and motility were evaluated in cultured human ovarian carcinoma cells. To study the effects of AZD1480 in vivo, we used MISIIR-TAg mice, a transgenic mouse model of ovarian carcinoma. Tumor growth in MISIIR-TAg mice was monitored and quantified in mice by weekly magnetic resonance imaging (MRI). Drug treatment-mediated alterations in gene expression were evaluated by microarray analysis and changes in the inflammatory response were evaluated by flow cytometry analysis of cells extracted from ovarian tumors, spleens and peritoneal washes. AZD1480 treatment significantly reduced primary ovarian tumor growth in transgenic mice. Microarray analysis showed changes in expression of genes involved in the acute immune response, such as Gbp6, Ifi44, Irgm, Igtp, Gzmb and Cd69. Analysis of immune cell populations by flow cytometry showed a significant decrease in the number and percent of T helper and T regulatory cells present in the peritoneal cavity of drug-treated mice compared to controls. As T regulatory cells are associated with a poor prognosis in ovarian cancer patients, the decrease of this subpopulation in drug-treated mice suggests a change in the tumor microenvironment that may contribute to reduced tumor growth. Taken together, these results indicate that targeting JAK2/STAT3 impedes ovarian tumor growth through complex mechanisms, including the reduction of primary tumor growth and inflammation in the tumor microenvironment. These findings highlight the potential utility of targeting the JAK2/STAT3 pathway for the treatment of ovarian cancer patients.

Citation Format: Galina Gritsina, Fang Xiao, Shane W. O'Brien, Marisa A. Maglaty, Ren-Huan Xu, Luis J. Sigal, Samuel Litwin, Denise C. Connolly. Targeting the JAK2/STAT3 pathway in ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1113. doi:10.1158/1538-7445.AM2014-1113

Endothelial C-type natriuretic peptide maintains vascular homeostasis

The endothelium plays a fundamental role in maintaining vascular homeostasis by releasing factors that regulate local blood flow, systemic blood pressure, and the reactivity of leukocytes and platelets. Accordingly, endothelial dysfunction underpins many cardiovascular diseases, including hypertension, myocardial infarction, and stroke. Herein, we evaluated mice with endothelial-specific deletion of Nppc, which encodes C-type natriuretic peptide (CNP), and determined that this mediator is essential for multiple aspects of vascular regulation. Specifically, disruption of CNP leads to endothelial dysfunction, hypertension, atherogenesis, and aneurysm. Moreover, we identified natriuretic peptide receptor-C (NPR-C) as the cognate receptor that primarily underlies CNP-dependent vasoprotective functions and developed small-molecule NPR-C agonists to target this pathway. Administration of NPR-C agonists promotes a vasorelaxation of isolated resistance arteries and a reduction in blood pressure in wild-type animals that is diminished in mice lacking NPR-C. This work provides a mechanistic explanation for genome-wide association studies that have linked the NPR-C (Npr3) locus with hypertension by demonstrating the importance of CNP/NPR-C signaling in preserving vascular homoeostasis. Furthermore, these results suggest that the CNP/NPR-C pathway has potential as a disease-modifying therapeutic target for cardiovascular disorders.

Glucocorticoid receptor agonist dexamethasone attenuates renal ischemia/reperfusion injury by up-regulating eNOS/iNOS

The aim of this study was to determine the effect of dexamethasone (DEX) on renal ischemia/reperfusion injury (IRI). C57BL/6 mice were randomly divided into Sham group, IRI group and DEX group. The mice in IRI and DEX groups subjected to renal ischemia for 60 min, were treated with saline or DEX (4 mg/kg, i.p.) 60 min prior to I/R. After 24 h of reperfusion, the renal function, renal pathological changes, activation of extracellular signal-regulated kinase (ERK) and glucocorticoid receptor (GR), and the levels of iNOS and eNOS were detected. The results showed DEX significantly decreased the damage to renal function and pathological changes after renal IRI. Pre-treatment with DEX reduced ERK activation and down-regulated the level of iNOS, whereas up-regulated the level of eNOS after renal IRI. DEX could further promote the activation of GR. These findings indicated GR activation confers preconditioning-like protection against acute IRI partially by up-regulating the ratio of eNOS/iNOS.

Improvement of lichenysin production in Bacillus licheniformis by replacement of native promoter of lichenysin biosynthesis operon and medium optimization

Lichenysin is a biodegradable surfactant with huge potential for recovering crude oil from the oil reservoir. The current production of lichenysin is made through fermentation from wild strain of Bacillus licheniformis, which is limited by low yield. The aim of this work was to improve lichenysin-producing capability of a wide strain B. licheniformis WX-02. Lichenysin produced from WX-02 was first extracted, purified, and identified. Through the substitution of the promoter of lichenysin biosynthesis operon, the mutants B. licheniformis WX02-P43lch, WX02-Pxyllch, and WX02-Psrflch were constructed with the constitutive promoter (P43), the xylose-inducible promoter (P xyl ), and the surfactin operon promoter (P srf ), respectively. A consistent change trend was observed between lichenysin production and lchAA gene transcription, confirming the strength of the promoters as an important factor for lichenysin synthesis. Among the three mutants, WX02-Psrflch produced the highest lichenysin yield. The production by the mutant WX02-Psrflch was further improved with the optimization of the major medium components including glucose, NH4NO3, and Na2HPO4/KH2PO4. Under 30 g/L glucose, 5 g/L NH4NO3, and 80 mM/60 mM Na2HPO4/KH2PO4, the strain WX02-Psrflch produced 2,149 mg/L lichenysin, a 16.8-fold improvement compared to that of wild strain WX-02.

MicroRNA-885-3p inhibits the growth of HT-29 colon cancer cell xenografts by disrupting angiogenesis via targeting BMPR1A and blocking BMP/Smad/Id1 signaling

The previous studies in this lab discovered that microRNA-885-3p (miR-885-3p) was regulated by a sulfated polysaccharide that bound to bone morphogenetic protein receptor, type IA (BMPR1A) to inhibit angiogenesis. However, its specific role and its mechanism of action in tumor cells have not been elucidated. We show that miR-885-3p markedly suppresses angiogenesis in vitro and in vivo. MiR-885-3p inhibits Smad1/5/8 phosphorylation and downregulates DNA-binding protein inhibitor ID-1 (Id1), a proangiogenic factor, by targeting BMPR1A, leading to impaired angiogenesis. Overexpression or silencing of BMPR1A affects angiogenesis in a Smad/Id1-dependent manner. We further show that miR-885-3p impairs the growth of HT-29 colon cancer cell xenografts in nude mice by suppressing angiogenesis through disruption of BMPR1A and Smad/Id1 signaling. These results support a novel role for miR-885-3p in tumor angiogenesis by targeting BMPR1A, which regulates a proangiogenic factor, and provide new evidence that targeting miRNAs might be an effective therapeutic strategy for improving colon cancer treatment.

Slc26a3 deficiency is associated with loss of colonic HCO3 (-) secretion, absence of a firm mucus layer and barrier impairment in mice

AIM

Downregulated in adenoma (DRA, Slc26a3) is a member of the solute carrier family 26 (SLC26), family of anion transporters, which is mutated in familial chloride-losing diarrhoea (CLD). Besides Cl(-) -rich diarrhoea, CLD patients also have a higher-than-average incidence of intestinal inflammation. In a search for potential explanations for this clinical finding, we investigated colonic electrolyte transport, the mucus layer and susceptibility against dextran sodium sulphate (DSS)-induced colitis in Slc26a3(-/-) mice.

METHODS

HCO3 (-) secretory (JHCO3 (-) ) and fluid absorptive rates were measured by single-pass perfusion in vivo and in isolated mid-distal colonic mucosa in Ussing chambers in vitro. Colonocyte intracellular pH (pHi ) was assessed fluorometrically, the mucus layer by immunohistochemistry and colitis susceptibility by the addition of DSS to the drinking water.

RESULTS

HCO3 (-) secretory (JHCO3- ) and fluid absorptive rates were strongly reduced in Slc26a3(-/-) mice compared to wild-type (WT) littermates. Despite an increase in sodium/hydrogen exchanger 3 (NHE3) mRNA and protein expression, and intact acid-activation of NHE3, the high colonocyte pH in Slc26a3(-/-) mice prevented Na(+) /H(+) exchange-mediated fluid absorption in vivo. Mucin 2 (MUC2) immunohistochemistry revealed the absence of a firm mucus layer, implying that alkaline secretion and/or an absorptive flux may be necessary for optimal mucus gel formation. Slc26a3(-/-) mice were highly susceptible to DSS damage.

CONCLUSIONS

Deletion of DRA results in severely reduced colonic HCO3 (-) secretory rate, a loss of colonic fluid absorption, a lack of a firmly adherent mucus layer and a severely reduced colonic mucosal resistance to DSS damage. These data provide potential pathophysiological explanations for the increased susceptibility of CLD patients to intestinal inflammation.

Role of mitochondrial electron transport chain dysfunction in Cr(VI)-induced cytotoxicity in L-02 hepatocytes

BACKGROUND

Hexavalent chromium [Cr(VI)] and its compounds (e.g. chromates), which are extensively used in numerous industrial processes including leather tanning and steel manufacturing, are considered as priority pollutants. There is growing evidence supporting that Cr(VI) could be a human carcinogen that induces primary liver cancer after oral exposure, and this sheds light on the importance of the investigation of Cr(VI)-induced hepatotoxicity. Although it is known that mitochondria are major targets for heavy metals, the mechanisms of electron transfer chain (ETC) dysfunction involved in Cr(VI)-induced cytotoxicity are unclear.

METHODS

In the present study, by using mitochondrial respiratory chain complex (MRCC) I inhibitor rotenone (ROT) and its substrates glutamate/malate (Glu/Mal), MRCC III inhibitor antimycin A (AA) and its substrate coenzyme Q (CoQ), and the antioxidant Vitamin C (Vit C), we aimed to elucidate the role of mitochondrial ETC dysfunction in Cr(VI)-induced cytotoxicity.

RESULTS

We found that Cr(VI) targeted and inhibited MRCC I and III to induce ETC dysfunction, which played an important role in Cr(VI)-induced cytotoxicity.

CONCLUSION

Our current data provides novel important insight into the mechanisms of mitochondrial ETC dysfunction in Cr(VI)-induced cytotoxicity in the hepatocytes, and we will be poised to develop new methods in the prevention and treatment of liver diseases involving mitochondrial ETC dysfunction for the occupational exposure population.