Anti-malaria drug artesunate protects bronchial epithelium from DNA damage induced by asthma

OBJECTIVE To investigate the genome protective effects of anti-malaria drug,artesunate in an experimental allergic asthma model.METHODS Mice were sensitized on day 0 and 7 and challenged on day 14 with 100μg house dust mite(HDM)via intratracheal administration.Artesunate(30mg·kg-1)was administered intra-peritoneally on day 6,7,8,13,14 and 15.Samples were collected on day 1,3 and 5 post last HDM-challenge for analysis of air way inflammation and DNA damage.Lung sections were immunofluorescence(IF)-stained for DNA double strand breaks(DSBs)markers,γH2AX and 53BP1.Levels of DNA repair proteins Ku70 and Rad51,which are involved in non-homologous end joining(NHEJ)and homologous recombination(HR)DNA DSB repair pathways respectively,were measured.To quantify cell death in asthmatic lung,TUNEL staining was performed.Comet assay,a single cell gel electrophoresis was employed to detect DNA damage induced by HDM in BEAS-2Bhuman bronchial epithelial cell line,in vitro.RESULTS Artesunate treatment significantly reduces immune cells infiltration in BAL fluid of asthmatic mice,collected on day 3 and 5 post-challenge.Importantly,artesuante is able to protect bronchial epithelium from DNA DSBs induced by asthma,as detected by the reduced level of γH2AX and 53BP1 foci formation in the nucleus.This genome protective effect is evident even on day 1 post-challenge,when immune cells infiltration remained high.This indicates that artesunate confers protection on bronchial epithelium in the presence of inflammation.Additionally,artesunate is also able to reduce cell death in asthmatic lung revealed by TUNEL assay and cleaved caspase 3 level.Interestingly,the levels of DNA repair proteins in artesuante-treated asthmatic mice are unchanged as compared to HDM-only mice,suggesting that artesunate treatment does not augment the level of DNA repair proteins.When human bronchial epithelial BEAS-2 Bcells were exposed to HDMin vitro,we observed an increase in the levels of DNA damage.Artesunate(60μmol·L-1)co-incubated with HDM is not able to prevent direct DNA damage induced by the allergen.Together,these studies suggest that the genome protective effect of artesunate in vivo may be attributed to physiological effects(such as its anti-inflammatory effects)rather than serving to directly prevent DNA damage.CONCULSION This study highlights a novel role for artesunate in protecting bronchial epithelial cells from asthma-induced DNA damage.

Non-typeable haemophilus influenzae-induced exacerbation on a cigarette smoke lung injury model:Protective effect of andrographolide

OBJECTIVE To develop a 2-week cigarette smoke(CS)acute lung injury model exacerbated by haemophilus influenzae(NTHi)and study the protective effect of andrographolide in this COPD model.METHODS Female BALB/c mice,6-8-week-old,were exposed to 4% 3R4 FCS delivered using aperistaltic pump daily for 2 weeks to induce an acute lung injury model.After 2 weeks of smoking,mice were inoculated intratracheally with NTHi to induce exacerbation on the model.Mice were sacrificed 48 h after last bacteria challenge and lung samples were collected for various analyses.RESULTS After developing a 2-week CS acute lung injury model exacerbated by NTHi,the CS+NTHi group was shown to have a higher inflammatory response,higher bacterial clearance,an upregulation of MMP12 mRNA levels and decrease in TIMP1 mRNA levels in the lungs.Administration of Andrographolide suppressed BALF lung cellular infiltrates,TNF-α,CXCL1/KC,IL-1βand 8-OHdG protein levels,together with increased HO-1 and GR mRNA levels and decreased MMP-8 and MMP-9 mRNA levels.Andrographolide was able to ameliorate lung histopathology as observed with H&E staining and inflammation scoring.Andrographolide was also shown to reduce Keap-1 level in lungs without affecting DJ-1 level.CONCLUSION This study demonstrates the protective effect of andrographolide in a novel 2-week CS acute lung injury model exacerbated by NTHi and presents it as a potential therapeutic for COPD.

Engineering humanized mice for improved hematopoietic reconstitution

Humanized mice are immunodeficient animals engrafted with human hematopoietic stem cells that give rise to various lineages of human blood cells throughout the life of the mouse. This article reviews recent advances in the generation of humanized mice, focusing on practical considerations. We discuss features of different immunodeficient recipient mouse strains, sources of human hematopoietic stem cells, advances in expansion and genetic modification of hematopoietic stem cells, and techniques to modulate the cytokine environment of recipient mice, in order to enhance reconstitution of specific human blood lineage cells. We highlight the opportunities created by new technologies and discuss practical considerations on how to make best use of the widening array of basic models for specific research applications.

Human CD34loCD133lo fetal liver cells support the expansion of human CD34hiCD133hi hematopoietic stem cells

We have recently discovered a unique CD34loCD133lo cell population in the human fetal liver （FL） that gives rise to cells in the hepatic lineage. In this study, we further characterized the biological functions of FL CD341~CD133~~ cells. Our findings show that these CD341~CD133I~ cells express markers of both endodermal and mesodermal lineages and have the capability to differentiate into hepatocyte and mesenchymal lineage cells by ex vivo differentiation assays. Furthermore, we show that CD34~~CD 133I~ cel Is express growth factors that are important for human hematopoietic stem cell （HSC） expansion： stem cell factor （SCF）, insulin-like growth factor 2 （IGF2）, C-X-C motif chemokine 12 （CXCL12）, and factors in the angiopoietin-like protein family. Co-culture of autologous FL HSCs and allogenic HSCs derived from cord blood with CD34loCD133lo cells supports and expands both types of HSCs.These findings are not only essential for extending our understanding of the HSC niche during the development of embryonic and fetal hematopoiesis but will also potentially benefit adult stem cell transplantations in clinics because expanded HSCs demonstrate the same capacity as primary cells to reconstitute the human immune system and mediate long-term hematopoiesis in vivo. Together,CD34loCD133lo cells not only serve as stem/progenitor cells for liver development but are also an essential component of the HSC niche in the human FL.