Essential role for CD103+ cells in the pathogenesis of spondyloarthritides

CD103+ Cells and Chemokine Receptor Expression in Breast Cancer

Mucosal environments harbour lymphocytes, which express several adhesion molecules, including intestinal homing receptors and integrin αE/β7 (CD103). CD103 binds E-cadherin, an integrin receptor expressed in intestinal endothelial cells. Its expression not only enables homing or retention of T lymphocytes at these sites but is also associated with increased T lymphocyte activation. However, it is not yet clear how CD103 expression is related to the clinical staging of breast cancer, which is determined by factors such as the size of the tumor (T), the involvement of nearby lymph nodes (N), and presence of metastasis (M). We examined the prognostic significance of CD103 by FACS in 53 breast cancer patients and 46 healthy controls enrolled, and investigated its expression, which contributes to lymphocyte recruitment in tumor tissue. Patients with breast cancer showed increased frequencies of CD103⁺, CD4⁺CD103⁺, and CD8⁺CD103⁺ cells compared to controls. CD103 was expressed at a high level on the surfaces of tumor-infiltrating lymphocytes in patients with breast cancer. Its expression in peripheral blood was not correlated with clinical TNM stage. To determine the localisation of CD103⁺ cells in breast tissue, tissue sections of breast tumors were stained for CD103. In tissue sections of breast tumors stained for CD103, its expression in T lymphocytes was higher compared to normal breast tissue. In addition, CD103⁺ cells expressed higher levels of receptors for inflammatory chemokines, compared to CD103^- cells. CD103⁺ cells in peripheral blood and tumor tissue might be an important source of tumor-infiltrating lymphocyte trafficking, homing, and retention in cancer patients.

Characterization of large extracellular vesicles (L-EV) derived from human regulatory macrophages (Mreg): novel mediators in wound healing and angiogenesis?

BACKGROUND

Large extracellular vesicles (L-EV) with a diameter between 1 and 10 µm are released by various cell types. L-EV contain and transport active molecules which are crucially involved in cell to cell communication. We have shown that secretory products of human regulatory macrophages (Mreg) bear pro-angiogenic potential in-vitro and our recent findings show that Mreg cultures also contain numerous large vesicular structures similar to L-EV with so far unknown characteristics and function.

AIM OF THIS STUDY

To characterize the nature of Mreg-derived L-EV (L-EV_Mreg) and to gain insights into their role in wound healing and angiogenesis.

METHODS

Mreg were differentiated using blood monocytes from healthy donors (N = 9) and L-EV_Mreg were isolated from culture supernatants by differential centrifugation. Characterization of L-EV_Mreg was performed by cell/vesicle analysis, brightfield/transmission electron microscopy (TEM), flow cytometry and proteome profiling arrays. The impact of L-EV_Mreg on wound healing and angiogenesis was evaluated by means of scratch and in-vitro tube formation assays.

RESULTS

Mreg and L-EV_Mreg show an average diameter of 13.73 ± 1.33 µm (volume: 1.45 ± 0.44 pl) and 7.47 ± 0.75 µm (volume: 0.22 ± 0.06 pl) respectively. Flow cytometry analyses revealed similarities between Mreg and L-EV_Mreg regarding their surface marker composition. However, compared to Mreg fewer L-EV_Mreg were positive for CD31 (P < 0.01), CD206 (P < 0.05), CD103 (P < 0.01) and CD45 (P < 0.05). Proteome profiling suggested that L-EV_Mreg contain abundant amounts of pro-angiogenic proteins (i.e. interleukin-8, platelet factor 4 and serpin E1). From a functional point of view L-EV_Mreg positively influenced in-vitro wound healing (P < 0.05) and several pro-angiogenic parameters in tube formation assays (all segment associated parameters, P < 0.05; number of meshes, P < 0.05).

CONCLUSION

L-EV_Mreg with regenerative and pro-angiogenic potential can be reproducibly isolated from in-vitro cultured human regulatory macrophages. We propose that L-EV_Mreg could represent a putative therapeutic option for the treatment of chronic wounds and ischemia-associated diseases.

Microbiota and Ocular Diseases

Recent advances have identified significant associations between the composition and function of the gut microbiota and various disorders in organ systems other than the digestive tract. Utilizing next-generation sequencing and multiomics approaches, the microbial community that possibly impacts ocular disease has been identified. This review provides an overview of the literature on approaches to microbiota analysis and the roles of commensal microbes in ophthalmic diseases, including autoimmune uveitis, age-related macular degeneration, glaucoma, and other ocular disorders. In addition, this review discusses the hypothesis of the "gut-eye axis" and evaluates the therapeutic potential of targeting commensal microbiota to alleviate ocular inflammation.

Identification of an intraocular microbiota

The current dogma in ophthalmology and vision research presumes the intraocular environment to be sterile. However, recent evidence of intestinal bacterial translocation into the bloodstream and many other internal organs including the eyes, found in healthy and diseased animal models, suggests that the intraocular cavity may also be inhabited by a microbial community. Here, we tested intraocular samples from over 1000 human eyes. Using quantitative PCR, negative staining transmission electron microscopy, direct culture, and high-throughput sequencing technologies, we demonstrated the presence of intraocular bacteria. The possibility that the microbiome from these low-biomass communities could be a contamination from other tissues and reagents was carefully evaluated and excluded. We also provide preliminary evidence that a disease-specific microbial signature characterized the intraocular environment of patients with age-related macular degeneration and glaucoma, suggesting that either spontaneous or pathogenic bacterial translocation may be associated with these common sight-threatening conditions. Furthermore, we revealed the presence of an intraocular microbiome in normal eyes from non-human mammals and demonstrated that this varied across species (rat, rabbit, pig, and macaque) and was established after birth. These findings represent the first-ever evidence of intraocular microbiota in humans.

Changes of CD103-expressing pulmonary CD4+ and CD8+ T cells in S. japonicum infected C57BL/6 mice

BACKGROUND

Recent studies have shown that CD103 is an important marker for tissue-resident memory T cells (TRM) which plays an important role in anti-infection. However, the role of CD103⁺ TRM was not elucidated in the progress of S. japonicum infection induced disease.

METHODS

6-8 weeks old C57BL/6 mice were infected by S. japonicum. Mice were sacrificed and the lungs were removed 5-6 weeks after infection. Immunofluorescent staining and Q-PCR were performed to identify the expression of CD103 molecule. Single cellular populations were made, percentages of CD103 on both CD4⁺ and CD8⁺ T lymphocytes were dynamical observed by flow cytometry (FCM). Moreover, the expression of memory T cells related molecules CD69 and CD62L, T cell function associated molecules CD107a, IFN-γ, IL-4, IL-9, and IL-10 were compared between CD103⁺ CD4⁺ and CD8⁺ T cells by FCM.

RESULTS

CD103⁺ cells were emerged in the lung of both naive and S. japonicum infected mice. Both the percentage and the absolute numbers of pulmonary CD4⁺ and CD8⁺ cells were increased after S. japonicum infection (P < 0.05). The percentage of CD103⁺ cells in CD8⁺ T cells decreased significantly at the early stage of S. japonicum infection (P < 0.05). Increased CD69, decreased CD62L and CD107a expressions were detected on both CD4⁺ and CD8⁺ CD103⁺ T cells in the lungs of infected mice (P < 0.05). Compared to CD8⁺ CD103⁺ T cells, CD4⁺ CD103⁺ T cells from infected mice expressed higher level of CD69 and lower level CD62L molecules (P < 0.05). Moreover, higher percentage of IL-4⁺, IL-9⁺ and IL-10⁺ cells on CD4⁺ CD103⁺ pulmonary T cells was found in infected mice (P < 0.05). Significantly increased IL-4 and IL-9, and decreased IFN-γ expressing cells were detected in CD8⁺CD103⁺ cells of infected mice (P < 0.05).

CONCLUSIONS

CD103-expressing pulmonary CD4⁺ and CD8⁺ T cells play important roles in mediating S. japonicum infection induced granulomatous inflammation in the lung.

The role of integrins in the pathogenesis of inflammatory bowel disease: Approved and investigational anti-integrin therapies

Inflammatory bowel disease (IBD) is characterized by uncontrolled inflammation in the gastrointestinal tract. The underlying pathobiology of IBD includes an increase in infiltrating gut-homing lymphocytes. Although lymphocyte homing is typically a tightly regulated and stepwise process involving multiple integrins and adhesion molecules expressed on endothelial cells, the distinct roles of integrin-expressing immune cells is not fully understood in the pathology of IBD. In this review, we detail the involvement of integrins expressed on specific lymphocyte subsets in the pathogenesis of IBD and discuss the current status of approved and investigational integrin-targeted therapies.

Review article: nonclinical and clinical pharmacology, pharmacokinetics and pharmacodynamics of etrolizumab, an anti-β7 integrin therapy for inflammatory bowel disease

BACKGROUND

Novel treatments with superior benefit-risk profiles are needed to improve the long-term prognosis of patients with inflammatory bowel disease (IBD). Etrolizumab-a monoclonal antibody that specifically targets β7 integrins-is currently under phase III clinical evaluation in IBD.

AIM

This review summarises the available pharmacological and pharmacokinetic/pharmacodynamic data for etrolizumab to provide a comprehensive understanding of its mechanism of action (MOA) and pharmacological effects.

METHODS

Published and internal unpublished data from nonclinical and clinical studies with etrolizumab are reviewed.

RESULTS

Etrolizumab exerts its effect via a unique dual MOA that inhibits both leucocyte trafficking to the intestinal mucosa and retention within the intestinal epithelial layer. The gut-selectivity of etrolizumab results from its specific targeting of the β7 subunit of α4β7 and αEβ7 integrins. Etrolizumab does not bind to α4β1 integrin, which mediates lymphocyte trafficking to tissues including the central nervous system, a characteristic underlying its favourable safety with regard to progressive multifocal leucoencephalopathy. Phase I/II studies in patients with ulcerative colitis (UC) showed linear pharmacokinetics when etrolizumab was administered subcutaneously at 100 mg or higher once every 4 weeks. This dose was sufficient to enable full β7 receptor occupancy in both blood and intestinal tissues of patients with moderate to severe UC. The phase II study results also suggested that patients with elevated intestinal expression of αE integrin may have an increased likelihood of clinical remission in response to etrolizumab treatment.

CONCLUSION

Etrolizumab is a gut-selective, anti-β7 integrin monoclonal antibody that may have therapeutic potential for the treatment of IBD.