{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T04:37:22Z","timestamp":1790743042204,"version":"4.1.0"},"reference-count":40,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2020,10,23]],"date-time":"2020-10-23T00:00:00Z","timestamp":1603411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Fundaci\u00f3n Conde de Valeciana","award":["SN"],"award-info":[{"award-number":["SN"]}]},{"name":"Departamento de Bioqu\u00edmica, Facultad de Medicina, UNAM","award":["SN"],"award-info":[{"award-number":["SN"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Ocular allergic diseases are frequently seen in ophthalmological clinical practice. Immunological damage is mediated by a local Th2 inflammatory microenvironment, accompanied by changes in circulating cell subsets, with more effector cells and fewer T regulatory cells (Tregs). This study aimed to evaluate the involvement of toll-like receptor 4 (TLR4) and \u03b1-melanocyte stimulating hormone (\u03b1-MSH) in the immune regulation associated with perennial allergic conjunctivitis (PAC). We performed an Ag-specific stimulation during 72 h of culturing with or without lipopolysaccharide (LPS) or \u03b1-MSH in peripheral blood mononuclear cells (PBMC), analyzing the cell subsets and cytokines induced by the stimuli. We also determined \u03b1-MSH in tear samples from healthy donors (HD) or PAC patients. Our findings demonstrate an immunological dysregulation characterized by an increased frequency of CD4+TLR4+ in the PBMC of patients with PAC, compared to HD. Most of these CD4+TLR4+ cells were also CD25+, and when \u03b1-MSH was added to the culture, the percentage of CD4+CD25+FoxP3+ increased significantly, while the percentage of CD69+ cells and cytokines IL-4 and IL-6 were significantly decreased. In tears, we found an increased concentration of \u03b1-MSH in PAC patients, compared with HD. These findings indicate a novel mechanism involved in controlling ocular allergic diseases, in which \u03b1-MSH diminishes the concentration of IL-6 and IL-4, restoring the frequency of Tregs and down-regulating CD4 activation. Moreover, we demonstrated the involvement of CD4+TLR4+ cells as an effector cell subset in ocular allergy.<\/jats:p>","DOI":"10.3390\/ijms21217861","type":"journal-article","created":{"date-parts":[[2020,10,23]],"date-time":"2020-10-23T08:59:28Z","timestamp":1603443568000},"page":"7861","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Increased Expression of TLR4 in Circulating CD4+T Cells in Patients with Allergic Conjunctivitis and In Vitro Attenuation of Th2 Inflammatory Response by Alpha-MSH"],"prefix":"10.3390","volume":"21","author":[{"given":"Jane E.","family":"Nieto","sequence":"first","affiliation":[{"name":"Department of Immunology and Research Unit, Institute of Ophthalmology \u201cConde de Valenciana Foundation\u201d, Ciudad de M\u00e9xico 06800, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Israel","family":"Casanova","sequence":"additional","affiliation":[{"name":"Department of Immunology and Research Unit, Institute of Ophthalmology \u201cConde de Valenciana Foundation\u201d, Ciudad de M\u00e9xico 06800, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juan Carlos","family":"Serna-Ojeda","sequence":"additional","affiliation":[{"name":"Department of Cornea and Refractive Surgery, Institute of Ophthalmology \u201cConde de Valenciana Foundation\u201d, Ciudad de M\u00e9xico 06800, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Enrique O.","family":"Graue-Hern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Department of Cornea and Refractive Surgery, Institute of Ophthalmology \u201cConde de Valenciana Foundation\u201d, Ciudad de M\u00e9xico 06800, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guillermo","family":"Quintana","sequence":"additional","affiliation":[{"name":"Department of Immunology and Research Unit, Institute of Ophthalmology \u201cConde de Valenciana Foundation\u201d, Ciudad de M\u00e9xico 06800, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alberto","family":"Salazar","sequence":"additional","affiliation":[{"name":"Department of Immunology and Research Unit, Institute of Ophthalmology \u201cConde de Valenciana Foundation\u201d, Ciudad de M\u00e9xico 06800, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3982-9097","authenticated-orcid":false,"given":"Mar\u00eda C.","family":"Jim\u00e9nez-Martinez","sequence":"additional","affiliation":[{"name":"Department of Immunology and Research Unit, Institute of Ophthalmology \u201cConde de Valenciana Foundation\u201d, Ciudad de M\u00e9xico 06800, Mexico"},{"name":"Department of Biochemistry, Faculty of Medicine, National Autonomous University of Mexico, Ciudad de M\u00e9xico 04510, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,10,23]]},"reference":[{"key":"ref_1","first-page":"607","article-title":"Allergic eye disease","volume":"6","author":"Kaufman","year":"2014","journal-title":"Pediatr. Clin. N. Am."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1097\/ACI.0b013e32834a9676","article-title":"Epidemiology of allergic conjunctivitis","volume":"11","author":"Rosario","year":"2011","journal-title":"Curr. Opin. Allergy Clin. Immunol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1097\/ACI.0000000000000100","article-title":"Trends in prevalence and treatment of ocular allergy","volume":"14","author":"Gomes","year":"2014","journal-title":"Curr. Opin. Allergy Clin. Immunol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/j.atmosenv.2018.05.006","article-title":"Pollen in the atmosphere of Mexico City and its impact on the health of the pediatric population","volume":"186","year":"2018","journal-title":"Atmos. Envrion."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"477","DOI":"10.1097\/ACI.0000000000000088","article-title":"T helper Subsets in Allergic Eye Disease","volume":"14","author":"Reyes","year":"2014","journal-title":"Curr. Opin. Allergy Clin. Immunol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1097\/ACI.0000000000000299","article-title":"An update on ocular allergy","volume":"16","author":"Shaker","year":"2016","journal-title":"Curr. Opin. Allergy Clin. Immunol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1016\/S1808-8694(15)30796-5","article-title":"Diversity of allergen exposure: Implications for the efficacy of environmental control","volume":"75","author":"Segundo","year":"2009","journal-title":"Braz. J. Otorhinolaryngol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1111\/j.1365-2249.2008.03716.x","article-title":"Allergy and the eye","volume":"153","author":"Leonardi","year":"2008","journal-title":"Clin. Exp. Immunol."},{"key":"ref_9","first-page":"443","article-title":"Intracellular IL-4, IL-5 and IFN-g as the main characteristic of CD4+CD30+T cells after allergen-stimulation, in patients with vernal keratoconjunctivitis","volume":"21","author":"Aguilar","year":"2015","journal-title":"Mol. Vis."},{"key":"ref_10","first-page":"919742","article-title":"An imbalance between frequency of CD4+CD25+FOXP3+ regulatory T cells and CCR4+ and CCR9+ circulating helper T cells is associated with active perennial allergic conjunctivitis","volume":"2013","author":"Santacruz","year":"2013","journal-title":"Clin. Dev. Immunol."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Reithofer, M., and Jahn-Schmid, B. (2017). Allergens with Protease Activity from House Dust Mites. Int. J. Mol. Sci., 18.","DOI":"10.3390\/ijms18071368"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"633","DOI":"10.1016\/j.it.2008.08.007","article-title":"The molecular basis of allergenicity","volume":"29","author":"Shakib","year":"2008","journal-title":"Trends Immunol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"679","DOI":"10.1016\/j.exer.2010.03.012","article-title":"Toll-like receptors in ocular surface disease","volume":"90","author":"Redfern","year":"2010","journal-title":"Exp. Eye Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1186\/1465-9921-12-125","article-title":"TLR4 signalling in pulmonary stromal cells is critical for inflammation and immunity in the airways","volume":"12","author":"Perros","year":"2011","journal-title":"Respir. Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1528","DOI":"10.1016\/j.ophtha.2005.04.009","article-title":"Expression of Toll-like receptors in healthy and allergic conjunctiva","volume":"112","author":"Bonini","year":"2005","journal-title":"Ophthalmology"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1059","DOI":"10.1016\/j.intimp.2004.04.011","article-title":"Anti-inflammatory effects of alpha-melanocyte-stimulating hormone against rat endotoxin-induced uveitis and the time course of inflammatory agents in aqueous humor","volume":"4","author":"Nishida","year":"2004","journal-title":"Int. Immunopharmacol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.jneuroim.2005.01.008","article-title":"The immunomodulating neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH) suppresses LPS-stimulated TLR4 with IRAK-M in macrophages","volume":"162","author":"Taylor","year":"2005","journal-title":"J. Neuroimmunol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"358","DOI":"10.1046\/j.1440-1711.2001.01022.x","article-title":"In vitro induction of CD25+ CD4+ regulatory T cells by the neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH)","volume":"79","author":"Taylor","year":"2001","journal-title":"Immunol. Cell Biol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"585","DOI":"10.1038\/nature07548","article-title":"Allergenicity resulting from functional mimicry of a Toll-like receptor complex protein","volume":"457","author":"Trompette","year":"2009","journal-title":"Nature"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1016\/j.molmed.2010.04.008","article-title":"House dust mite allergens in asthma and allergy","volume":"16","author":"Thomas","year":"2010","journal-title":"Trends Mol. Med."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"41","DOI":"10.4049\/jimmunol.179.1.41","article-title":"Cutting edge: T cells respond to lipopolysaccharide innately via TLR4 signaling","volume":"179","author":"Cahalon","year":"2007","journal-title":"J. Immunol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"7118","DOI":"10.1038\/s41598-018-25549-8","article-title":"VIPER regulates naive T cell activation and effector responses: Implication in TLR4 associated acute stage T cell responses","volume":"8","author":"Sahoo","year":"2018","journal-title":"Sci. Rep."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"276","DOI":"10.4110\/in.2017.17.5.276","article-title":"IL-17A-producing Foxp3+ regulatory T cells and human diseases","volume":"17","author":"Jung","year":"2017","journal-title":"Immune Netw."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1033","DOI":"10.1126\/science.1078231","article-title":"Toll pathway-dependent blockade of CD4+ CD25+T cell-mediated suppression by dendritic cells","volume":"299","author":"Pasare","year":"2003","journal-title":"Science"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1016\/j.immuni.2004.07.009","article-title":"Recognition of the peripheral self by naturally arising CD25+CD4+T cell receptors","volume":"21","author":"Hsieh","year":"2004","journal-title":"Immunity"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.autrev.2008.08.002","article-title":"Tregs are regulated by cytokines: Implications for autoimmunity","volume":"8","year":"2008","journal-title":"Autoimmun. Rev."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1016\/j.it.2004.12.006","article-title":"CD69 is an immunoregulatory molecule induced following activation","volume":"26","author":"Sancho","year":"2005","journal-title":"Trends Immunol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.jneuroim.2014.01.010","article-title":"SV\u03b1-MSH, a novel \u03b1-melanocyte stimulating hormone analog, ameliorates autoimmune encephalomyelitis through inhibiting autoreactive CD4+T cells activation","volume":"269","author":"Fang","year":"2014","journal-title":"J. Neuroimmunol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"353","DOI":"10.4049\/jimmunol.171.1.353","article-title":"\u03b1-Melanocyte-stimulating hormone inhibits allergic airway inflammation","volume":"171","author":"Raap","year":"2003","journal-title":"J. Immunol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1111\/j.1365-2567.2008.02832.x","article-title":"The modulatory effects of lipopolysaccharide-stimulated B cells on differential T-cell polarization","volume":"125","author":"Xu","year":"2008","journal-title":"Immunology"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"979","DOI":"10.1152\/physrev.2000.80.3.979","article-title":"Corticotropin releasing hormone and proopiomelanocortin involvement in the cutaneous response to stress","volume":"80","author":"Slominski","year":"2000","journal-title":"Physiol. Rev."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/srep18619","article-title":"\u03b1-Melanocyte-stimulating hormone ameliorates ocular surface dysfunctions and lesions in a scopolamine-induced dry eye model via PKA-CREB and MEK-Erk pathways","volume":"5","author":"Ru","year":"2015","journal-title":"Sci. Rep."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1066","DOI":"10.1111\/cea.12759","article-title":"Regulation of melanocortin 1 receptor in allergic rhinitis in vitro and in vivo","volume":"46","author":"Kleiner","year":"2016","journal-title":"Clin. Exp. Allergy"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.jtos.2018.09.006","article-title":"The ocular surface in children: A review of current knowledge and meta-analysis of tear film stability and tear secretion in children","volume":"17","author":"Briggs","year":"2019","journal-title":"Ocul. Surf."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1097\/ICL.0000000000000369","article-title":"New Insights into the Lipid Layer of the Tear Film and Meibomian Glands","volume":"43","author":"Arita","year":"2017","journal-title":"Eye Contact Lens."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"202","DOI":"10.1016\/j.ejphar.2010.10.100","article-title":"Melanocortin-5 receptor and sebogenesis","volume":"660","author":"Zhang","year":"2011","journal-title":"Eur. J. Pharmacol."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"House, J.S., Zhu, S., Ranjan, R., Linder, K., and Smart, R.C. (2010). C\/EBPalpha and C\/EBPbeta are required for Sebocyte differentiation and stratified squamous differentiation in adult mouse skin. PLoS ONE, 5.","DOI":"10.1371\/journal.pone.0009837"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"716","DOI":"10.1165\/rcmb.2009-0420OC","article-title":"\u03b1-Melanocyte-stimulating hormone inhibits tumor necrosis factor \u03b1-stimulated MUC5AC expression in human nasal epithelial cells","volume":"44","author":"Lee","year":"2011","journal-title":"Am. J. Respir. Cell Mol. Biol."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Salazar, A., Casanova-M\u00e9ndez, I., Pacheco-Quito, M., Vel\u00e1zquez-Soto, H., Ayala-Balboa, J., Graue-Hern\u00e1ndez, E.O., Seraf\u00edn-L\u00f3pez, J., and Jim\u00e9nez-Mart\u00ednez, M.C. (2019). Low Expression of IL-10 in Circulating Bregs and Inverted IL-10\/TNF-\u03b1 Ratio in Tears of Patients with Perennial Allergic Conjunctivitis: A Preliminary Study. Int. J. Mol. Sci., 20.","DOI":"10.3390\/ijms20051035"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"4850","DOI":"10.3390\/ijms16034850","article-title":"Expression of IL-8, IL-6 and IL-1\u03b2 in Tears as a Main Characteristic of the Immune Response in Human Microbial Keratitis","volume":"16","author":"Santacruz","year":"2015","journal-title":"Int. J. Mol. Sci."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/21\/21\/7861\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:26:47Z","timestamp":1760178407000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/21\/21\/7861"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,10,23]]},"references-count":40,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2020,11]]}},"alternative-id":["ijms21217861"],"URL":"https:\/\/doi.org\/10.3390\/ijms21217861","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,10,23]]}}}