Chemokine stimulation promotes enterocyte migration through laminin-specific integrins

Mastocytosis and intraepithelial lymphocytosis in the ileum and colon characterize chronic Toxoplasma gondii infection in mice

Toxoplasma gondii is the causative agent of toxoplasmosis, a common zoonotic disease affecting vertebrates with high global incidence. For the parasite to disseminate throughout the body, it crosses the intestinal barrier, triggering inflammatory reactions. This study aimed to assess the tissue response in the ileum and colon of mice following chronic infection with T. gondii. Fourteen mice were divided into two groups: the infected group received 1000 T. gondii oocysts via gavage, and after 60 days, the mice were euthanized. The ileum and colon were collected and processed for histological analysis, inflammatory marker measurement and myenteric neuron analysis. Chronic infection resulted in a significant increase in intraepithelial lymphocytes and mast cells, as well as morphometric changes such as increased total intestinal wall thickness of the ileum, crypt depth, collagen fiber area, and a decrease in myeloperoxidase activity, without altering nitric oxide levels. While the number of myenteric neurons remained unchanged, there was an increase in vasoactive intestinal peptide expression. These results suggest persistence intestinal inflammatory stimuli in chronic T. gondii infection.

Poly-l-lactic acid microspheres delay aging of epidermal stem cells in rat skin

Objective

Injectable skin fillers offer a wider range of options for cutaneous anti-aging and facial rejuvenation. PLLA microspheres are increasingly favored as degradable and long-lasting fillers. The present study focused solely on the effect of PLLA on dermal collagen, without investigating its impact on the epidermis. In this study, we investigated the effects of PLLA microspheres on epidermal stem cells (EpiSCs).

Methods

Different concentrations of PLLA microspheres on epidermal stem cells (EpiSCs) in vitro through culture, and identification of primary rat EpiSCs. CCK-8 detection, apoptosis staining, flow cytometry, Transwell assay, wound healing assay, q-PCR analysis, and immunofluorescence staining were used to detect the effects of PLLA on EpiSCs. Furthermore, we observed the effect on the epidermis by injecting PLLA into the dermis of the rat skin in vivo.

Results

PLLA microspheres promote cell proliferation and migration while delaying cell senescence and maintaining its stemness. In vitro, Intradermal injection of PLLA microspheres in the rat back skin resulted in delayed aging, as evidenced by histological and immunohistochemical staining of the skin at 2, 4, and 12 weeks of follow-up.

Conclusion

This study showed the positive effects of PLLA on rat epidermis and EpiSCs, while providing novel insights into the anti-aging mechanism of PLLA.

Immunoexpression of CXCL12 and CXCR4 in Radicular Cysts, Dentigerous Cysts, and Odontogenic Keratocysts

The aim of this study was to evaluate the immunoexpression of chemokine CXCL12 and its receptor CXCR4 in radicular cysts (RCs), dentigerous cysts (DCs), and odontogenic keratocysts (OKCs), and to correlate the findings with morphologic parameters of RCs (inflammatory infiltrate and cystic epithelium). Twenty RCs, 20 DCs, and 20 OKCs were submitted to immunohistochemistry. The percentages of cytoplasmic (CXCL12 and CXCR4) and nuclear (CXCR4) staining in epithelial and fibrous capsule cells were determined. RCs and DCs exhibited higher epithelial expression of CXCL12 than OKCs ( P <0.05). The expression of CXCL12 in the fibrous capsule was higher in DCs than in RCs and OKCs ( P <0.05). Higher cytoplasmic expression of CXCR4 was observed in the epithelial lining and fibrous capsule of RCs and DCs compared with OKCs ( P <0.05). In the fibrous capsule, DCs exhibited higher nuclear expression of CXCR4 than OKCs ( P <0.05). No significant differences in the immunoexpression of CXCL12 or CXCR4 were observed according to the morphologic parameters of RCs ( P >0.05). Strong positive correlations were found between cytoplasmic and nuclear expression of CXCR4 in the epithelial lining of RCs and DCs and in the fibrous capsule of all groups ( P <0.05). The results suggest the participation of CXCL12 and CXCR4 in the pathogenesis of RCs, DCs, and OKCs. These proteins may be particularly relevant for the development of odontogenic cysts with less aggressive biological behavior, irrespective of their nature (inflammatory or developmental). In RCs, the expression of CXCL12 and CXCR4 may not be related to the intensity of the inflammatory infiltrate or the status of cystic epithelium.

Immunoexpression of CXCL12 and CXCR4 in sporadic and Gorlin-Goltz syndrome-related odontogenic keratocysts

Background

Differences in the pathogenesis and biological behavior of sporadic and Gorlin-Goltz syndrome-related odontogenic keratocysts (OKCs) have been reported, but the underlying mechanisms are not fully elucidated. Chemokine CXCL12 and its main receptor CXCR4 regulate important events in the pathogenesis of several lesions.

Material and Methods

This study evaluated the immunoexpression of CXCL12 and CXCR4 in sporadic and syndromic OKCs. Twenty-two sporadic OKCs and 22 syndromic OKCs were subjected to immunohistochemistry. The percentages of cytoplasmic (CXCL12 and CXCR4) and nuclear (CXCR4) staining in epithelial and fibrous capsule cells were determined. The results were analyzed statistically using the nonparametric Mann-Whitney test and Spearman correlation test (p<0.05).

Results

Higher cytoplasmic expression of CXCL12 was observed in the epithelial lining and fibrous capsule of sporadic OKCs compared to syndromic OKCs (p<0.001). No statistically significant differences in the cytoplasmic expression of CXCR4 were observed between syndromic OKCs and sporadic OKCs (p>0.05). Compared to syndromic OKCs, sporadic OKCs exhibited higher nuclear expression of CXCR4 in the epithelial lining and lower immunoexpression in the fibrous capsule (p<0.05). In the epithelial lining of syndromic OKCs, positive correlation was observed between cytoplasmic and nuclear expressions of CXCR4 (p=0.003). In the fibrous capsule of syndromic OKCs and sporadic OKCs, cytoplasmic and nuclear expressions of CXCR4 were positively correlated (p<0.001).

Conclusions

The results suggest a potential participation of CXCL12 and CXCR4 in the development of OKCs. The heterogeneous expression of these proteins in syndromic and sporadic OKCs may reflect differences in their pathogenesis and biological behavior. Key words:Odontogenic keratocyst, CXCL12, CXCR4, Immunohistochemistry.

Genomics of immune response to typhoid and cholera vaccines

Considerable variation in antibody response (AR) was observed among recipients of an injectable typhoid vaccine and an oral cholera vaccine. We sought to find whether polymorphisms in genes of the immune system, both innate and adaptive, were associated with the observed variation in response. For both vaccines, we were able to discover and validate several polymorphisms that were significantly associated with immune response. For the typhoid vaccines, these polymorphisms were on genes that belonged to pathways of polysaccharide recognition, signal transduction, inhibition of T-cell proliferation, pro-inflammatory signalling and eventual production of antimicrobial peptides. For the cholera vaccine, the pathways included epithelial barrier integrity, intestinal homeostasis and leucocyte recruitment. Even though traditional wisdom indicates that both vaccines should act as T-cell-independent antigens, our findings reveal that the vaccines induce AR using different pathways.

Genomic correlates of variability in immune response to an oral cholera vaccine

Cholera is endemic to many countries. Recent major outbreaks of cholera have prompted World Health Organization to recommend oral cholera vaccination as a public-health strategy. Variation in percentage of seroconversion upon cholera vaccination has been recorded across populations. Vaccine-induced responses are influenced by host genetic differences. We have investigated association between single-nucleotide polymorphic (SNP) loci in and around 296 immunologically relevant genes and total anti-lipopolysaccharide (LPS) antibody response to a killed whole-cell vaccine, comprising LPS from multiple strains of Vibrio cholerae. Titers derived from standard vibriocidal assays were also analyzed to gain further insights on validated SNP associations. Vaccination was administered to 1000 individuals drawn from India. Data on two independent random subsets, each comprising ∼500 vaccinees, were used for discovery of genomic associations and validation, respectively. Significant associations of four SNPs and haplotypes in three genes (MARCO, TNFAIP3 and CXCL12) with AR were discovered and validated, of which two in TNFAIP3 and CXCL12 were also significantly associated with immunity (fourfold increase in vibriocidal titers). CXCL12 is a neutrophil and lymphocyte chemoattractant that is upregulated in response to V. cholerae infection. LPS in the vaccine possibly provides signals that mimic those of the live bacterium. TNFAIP3 promotes intestinal epithelial barrier integrity and provides tight junction protein regulation; possible requirements for adequate response to the vaccine. LPS is a potent activator of innate immune responses and a ligand of MARCO. Variants in this gene have been found to be associated with LPS response, but not with high vibriocidal titer level.

Engineering functional epithelium for regenerative medicine and in vitro organ models: a review

Recent advances in the fields of microfabrication, biomaterials, and tissue engineering have provided new opportunities for developing biomimetic and functional tissues with potential applications in disease modeling, drug discovery, and replacing damaged tissues. An intact epithelium plays an indispensable role in the functionality of several organs such as the trachea, esophagus, and cornea. Furthermore, the integrity of the epithelial barrier and its degree of differentiation would define the level of success in tissue engineering of other organs such as the bladder and the skin. In this review, we focus on the challenges and requirements associated with engineering of epithelial layers in different tissues. Functional epithelial layers can be achieved by methods such as cell sheets, cell homing, and in situ epithelialization. However, for organs composed of several tissues, other important factors such as (1) in vivo epithelial cell migration, (2) multicell-type differentiation within the epithelium, and (3) epithelial cell interactions with the underlying mesenchymal cells should also be considered. Recent successful clinical trials in tissue engineering of the trachea have highlighted the importance of a functional epithelium for long-term success and survival of tissue replacements. Hence, using the trachea as a model tissue in clinical use, we describe the optimal structure of an artificial epithelium as well as challenges of obtaining a fully functional epithelium in macroscale. One of the possible remedies to address such challenges is the use of bottom-up fabrication methods to obtain a functional epithelium. Modular approaches for the generation of functional epithelial layers are reviewed and other emerging applications of microscale epithelial tissue models for studying epithelial/mesenchymal interactions in healthy and diseased (e.g., cancer) tissues are described. These models can elucidate the epithelial/mesenchymal tissue interactions at the microscale and provide the necessary tools for the next generation of multicellular engineered tissues and organ-on-a-chip systems.

RNA-seq analysis of mucosal immune responses reveals signatures of intestinal barrier disruption and pathogen entry following Edwardsiella ictaluri infection in channel catfish, Ictalurus punctatus

The mucosal surfaces of fish (gill, skin, gastrointestinal tract) are important sites of bacterial exposure and host defense mechanisms. In mammalian systems, the intestinal epithelium is well characterized as both a selectively permeable barrier regulated by junctional proteins and as a primary site of infection for a number of enteric pathogens including viruses, bacteria, and parasites. The causative bacterium of enteric septicemia of catfish, Edwardsiella ictaluri, is believed to gain entry through the intestinal epithelium, with previous research using a rat intestinal epithelial cell line (IEC-6) indicating actin polymerization and receptor-mediated endocytosis as potential mechanisms of uptake. Here, we utilized high-throughput RNA-seq to characterize the role of the intestinal epithelial barrier following E. ictaluri challenge. A total of 197.6 million reads were obtained and assembled into 176,481 contigs with an average length of 893.7 bp and N50 of 1676 bp. The assembled contigs contained 14,457 known unigenes, including 2719 genes not previously identified in other catfish transcriptome studies. Comparison of digital gene expression between challenged and control samples revealed 1633 differentially expressed genes at 3 h, 24 h, and 3 day following exposure. Gene pathway analysis of the differentially expressed gene set indicated the centrality of actin cytoskeletal polymerization/remodelling and junctional regulation in pathogen entry and subsequent inflammatory responses. The expression patterns of fifteen differentially expressed genes related to intestinal epithelial barrier dysfunction were validated by quantitative real-time RT-PCR (average correlation coeff. 0.92, p < 0.001). Our results set a foundation for future studies comparing mechanisms of pathogen entry and mucosal immunity across several important catfish pathogens including E. ictaluri, Edwardsiellatarda, Flavobacterium columnare, and virulent atypical Aeromonas hydrophila. Understanding of molecular mechanisms of pathogen entry during infection will provide insight into strategies for selection of resistant catfish brood stocks against various diseases.