In situ production and secretion of proteins endow therapeutic benefit against psoriasiform dermatitis and melanoma.

Genetic medicines have the potential to treat various diseases; however, certain ailments including inflammatory diseases and cancer would benefit from control over extracellular localization of therapeutic proteins. A critical gap therefore remains the need to develop and incorporate methodologies that allow for posttranslational control over expression dynamics, localization, and stability of nucleic acid-generated protein therapeutics. To address this, we explored how the body's endogenous machinery controls protein localization through signal peptides (SPs), including how these motifs could be incorporated modularly into therapeutics. SPs serve as a virtual zip code for mRNA transcripts that direct the cell where to send completed proteins within the cell and the body. Utilizing this signaling biology, we incorporated secretory SP sequences upstream of mRNA transcripts coding for reporter, natural, and therapeutic proteins to induce secretion of the proteins into systemic circulation. SP sequences generated secretion of various engineered proteins into the bloodstream following intravenous, intramuscular, and subcutaneous SP mRNA delivery by lipid, polymer, and ionizable phospholipid delivery carriers. SP-engineered etanercept/TNF-α inhibitor proteins demonstrated therapeutic efficacy in an imiquimod-induced psoriasis model by reducing hyperkeratosis and inflammation. An SP-engineered anti-PD-L1 construct mediated mRNA encoded proteins with longer serum half-lives that reduced tumor burden and extended survival in MC38 and B16F10 cancer models. The modular nature of SP platform should enable intracellular and extracellular localization control of various functional proteins for diverse therapeutic applications.

GLUT3 promotes macrophage signaling and function via RAS-mediated endocytosis in atopic dermatitis and wound healing.

The facilitative GLUT1 and GLUT3 hexose transporters are expressed abundantly in macrophages, but whether they have distinct functions remains unclear. We confirmed that GLUT1 expression increased after M1 polarization stimuli and found that GLUT3 expression increased after M2 stimulation in macrophages. Conditional deletion of Glut3 (LysM-Cre Glut3fl/fl) impaired M2 polarization of bone marrow-derived macrophages. Alternatively activated macrophages from the skin of patients with atopic dermatitis showed increased GLUT3 expression, and a calcipotriol-induced model of atopic dermatitis was rescued in LysM-Cre Glut3fl/fl mice. M2-like macrophages expressed GLUT3 in human wound tissues as assessed by transcriptomics and costaining, and GLUT3 expression was significantly decreased in nonhealing, compared with healing, diabetic foot ulcers. In an excisional wound healing model, LysM-Cre Glut3fl/fl mice showed significantly impaired M2 macrophage polarization and delayed wound healing. GLUT3 promoted IL-4/STAT6 signaling, independently of its glucose transport activity. Unlike plasma membrane-localized GLUT1, GLUT3 was localized primarily to endosomes and was required for the efficient endocytosis of IL-4Rα subunits. GLUT3 interacted directly with GTP-bound RAS in vitro and in vivo through its intracytoplasmic loop domain, and this interaction was required for efficient STAT6 activation and M2 polarization. PAK activation and macropinocytosis were also impaired without GLUT3, suggesting broader roles for GLUT3 in the regulation of endocytosis. Thus, GLUT3 is required for efficient alternative macrophage polarization and function, through a glucose transport-independent, RAS-mediated role in the regulation of endocytosis and IL-4/STAT6 activation.

Sudden Conjunctivitis, Lymphopenia, and Rash Combined With Hemodynamic Changes (SCoRCH) After Trimethoprim-Sulfamethoxazole Use: A Case Series Study of a Hypersensitivity Reaction.

Importance: Trimethoprim-sulfamethoxazole (TMP-SMX) hypersensitivity reaction, ranging from circulatory shock to aseptic meningitis and respiratory failure, is a potentially life-threatening condition with dermatologic relevance. Objective: To describe the mucocutaneous findings and clinical features of TMP-SMX hypersensitivity reaction. Design, Setting, and Participants: This was a retrospective case series study of 7 patients who developed a characteristic rash, hemodynamic changes, and end-organ dysfunction after treatment with TMP-SMX at a large university hospital system during January 2013 to March 2022. Exposures: Treatment with TMP-SMX within 2 weeks of the reaction. Main Outcome and Measures: Descriptions of the condition, including the demographic information of the affected population, the reaction timeline, and mucocutaneous and clinical features. Results: The cohort comprised 7 patients (median [range] age, 20 [15-66] years; 4 female and 3 male). The most common mucocutaneous findings were generalized sunburn-like erythema without scale, conjunctivitis, and mild facial and acral edema. Three patients had previous exposure to TMP-SMX and developed symptoms in 1 day or less, while those without prior exposure presented from 4 to 11 days after drug initiation. Among the 7 patients, 6 had fever, 7 had hypotension, and 7 had tachycardia. All patients had lymphopenia and evidence of end-organ dysfunction with either kidney or liver involvement. Median (range) time to resolution was 72 (48-96) hours. Conclusions and Relevance: This retrospective case series indicates that SCoRCH (sudden conjunctivitis, lymphopenia, and rash combined with hemodynamic changes) should be considered in the differential diagnosis of patients presenting with acute generalized sunburn-like erythema, conjunctivitis, systemic symptoms, and hemodynamic changes in the setting of recent TMP-SMX use.