Revisiting the Road Map of Medullary Thymic Epithelial Cell Differentiation.

The basic two-step terminal differentiation model of the medullary thymic epithelial cell (mTEC) lineage from immature MHC class II (MHCII)lo to mature MHCIIhi mTECs has recently been extended to include a third stage, namely the post-Aire MHCIIlo subset as identified by lineage-tracing models. However, a suitable surface marker distinguishing the phenotypically overlapping pre- from the post-Aire MHCIIlo stage has been lacking. In this study, we introduce the lectin Tetragonolobus purpureas agglutinin (TPA) as a novel cell surface marker that allows for such delineation. Based on our data, we derived the following sequence of mTEC differentiation: TPAloMHCIIlo → TPAloMHCIIhi → TPAhiMHCIIhi → TPAhiMHCIIlo Surprisingly, in the steady-state postnatal thymus TPAloMHCIIlo pre-Aire rather than terminally differentiated post-Aire TPAhiMHCIIlo mTECs were marked for apoptosis at an exceptionally high rate of ∼70%. Hence, only the minor cycling fraction of the MHCIIlo subset (<20%) potentially qualified as mTEC precursors. FoxN1 expression inversely correlated with the fraction of slow cycling and apoptotic cells within the four TPA subsets. TPA also further subdivided human mTECs, although with different subset distribution. Our revised road map emphazises close parallels of terminal mTEC development with that of skin, undergoing an alternative route of cell death, namely cornification rather than apoptosis. The high rate of apoptosis in pre-Aire MHCIIlo mTECs points to a "quality control" step during early mTEC differentiation.

Dissecting and modeling the emergent murine TEC compartment during ontogeny.

The origin of the thymic epithelium, i.e. the cortical (cTEC) and medullary (mTEC) epithelial cells, from bipotent stem cells through TEC progenitors and lineage-specific progeny still remains poorly understood. We sought to obtain an unbiased view of the incipient emergence of TEC subsets by following embryonic TEC development based on co-expression of EpCAM, CD80 and MHC class II (MHCII) on non-hematopoietic (CD45- ) thymic stromal cells in wild-type BL6 mice. Using a combination of ex vivo analysis, Re-aggregate Thymic Organ Culture (RTOC) reconstitution assays and mathematical modeling, we traced emergent lineage commitment in murine embryonic TECs. Both experimental and mathematical datasets supported the following developmental sequence: MHCII- CD80- → MHCIIlo CD80- → MHCIIhi CD80- → MHCIIhi CD80hi TECs, whereby MHCIIhi CD80- and MHCIIhi CD80hi TECs bear features of cTECs and mTECs respectively. These emergent MHCIIhi CD80- cTECs directly generate mature MHCIIhi CD80hi mTECs in vivo and in vitro, thus supporting the asynchronous model of TEC lineage commitment.

Arginine-selective bioconjugation with 4-azidophenyl glyoxal: application to the single and dual functionalisation of native antibodies.

Here, we introduce 4-azidophenyl glyoxal (APG) as an efficient plug-and-play reagent for the selective functionalisation of arginine residues in native antibodies. The selective reaction between APG and arginines' guanidine groups allowed a facile introduction of azide groups on the monoclonal antibody trastuzumab (plug stage). These pre-functionalised antibody-azide conjugates were then derivatised during the "play stage" via a biorthogonal cycloaddition reaction with different strained alkynes. This afforded antibody-fluorophore and antibody-oligonucleotide conjugates, all showing preserved antigen selectivity and high stability in human plasma. Due to a lower content of arginines compared to lysines in native antibodies, this approach is thus attractive for the preparation of more homogeneous conjugates. This method proved to be orthogonal to classical lysine-based conjugation and allowed straightforward generation of dual-payload antibody.

Acyl Fluorides: Fast, Efficient, and Versatile Lysine-Based Protein Conjugation via Plug-and-Play Strategy.

We report a plug-and-play strategy for the preparation of functionally enhanced antibodies with a defined average degree of conjugation (DoC). The first stage (plug) allows the controllable and efficient installation of azide groups on lysine residues of a native antibody using 4-azidobenzoyl fluoride. The second step (play) allows for versatile antibody functionalization with a single payload or combination of payloads, such as a toxin, a fluorophore, or an oligonucleotide, via copper-free strain-promoted azide-alkyne cycloaddition (SPAAC). It is notable that in comparison to a classical N-hydroxysuccinimide ester (NHS) strategy, benzoyl fluorides show faster and more efficient acylation of lysine residues in a PBS buffer. This translates into better control of the DoC and enables the efficient and fast functionalization of delicate biomolecules at low temperature.

Overlapping gene coexpression patterns in human medullary thymic epithelial cells generate self-antigen diversity.

Promiscuous expression of numerous tissue-restricted self-antigens (TRAs) in medullary thymic epithelial cells (mTECs) is essential to safeguard self-tolerance. A distinct feature of promiscuous gene expression is its mosaic pattern (i.e., at a given time, each self-antigen is expressed only in 1-3% of mTECs). How this mosaic pattern is generated at the single-cell level is currently not understood. Here, we show that subsets of human mTECs expressing a particular TRA coexpress distinct sets of genes. We identified three coexpression groups comprising overlapping and complementary gene sets, which preferentially mapped to certain chromosomes and intrachromosomal gene clusters. Coexpressed gene loci tended to colocalize to the same nuclear subdomain. The TRA subsets aligned along progressive differentiation stages within the mature mTEC subset and, in vitro, interconverted along this sequence. Our data suggest that single mTECs shift through distinct gene pools, thus scanning a sizeable fraction of the overall repertoire of promiscuously expressed self-antigens. These findings have implications for the temporal and spatial (re)presentation of self-antigens in the medulla in the context of tolerance induction.

Misinitiation of intrathymic MART-1 transcription and biased TCR usage explain the high frequency of MART-1-specific T cells.

Immunity to tumor differentiation antigens, such as melanoma antigen recognized by T cells 1 (MART-1), has been comprehensively studied. Intriguingly, CD8(+) T cells specific for the MART-1(26(27)-35) epitope in the context of HLA-A0201 are about 100 times more abundant compared with T cells specific for other tumor-associated antigens. Moreover, MART-1-specific CD8(+) T cells show a highly biased usage of the Vα-region gene TRAV12-2. Here, we provide independent support for this notion, by showing that the combinatorial pairing of different TCRα- and TCRß- chains derived from HLA-A2-MART-1(26-35) -specific CD8(+) T-cell clones is unusually permissive in conferring MART-1 specificity, provided the CDR1α TRAV12-2 region is used. Whether TCR bias alone accounts for the unusual abundance of HLA-A2-MART-1(26-35) -specific CD8(+) T cells has remained conjectural. Here, we provide an alternative explanation: misinitiated transcription of the MART-1 gene resulting in truncated mRNA isoforms leads to lack of promiscuous transcription of the MART-1(26-35) epitope in human medullary thymic epithelial cells and, consequently, evasion of central self-tolerance toward this epitope. Thus, biased TCR usage and leaky central tolerance might act in an independent and additive manner to confer high frequency of MART-1(26-35) -specific CD8(+) T cells.

"I Have Remained Strong Because of That Food": Acceptability and Use of Lipid-Based Nutrient Supplements Among Pregnant HIV-Infected Ugandan Women Receiving Combination Antiretroviral Therapy.

We evaluated the acceptability and use of macronutrient supplementation among HIV-infected pregnant Ugandan women receiving antiretroviral therapy in a clinical study (NCT 00993031). We first conducted formative research among 56 pregnant and lactating women to select a supplement regimen. Acceptability and use of the supplementation regimen (35 sachets of lipid-based nutrient supplements (LNS) and 4 or 6 kg of instant soy porridge for the household provided monthly) were evaluated among 87 pregnant women. Organoleptic assessments of LNS were favorable. Participants reported consuming LNS a mean of 6.1 days per week, and adherence to recommended consumption behaviors (e.g. frequency, quantity, not sharing) was >80 %. Few women reported negative social consequences of supplementation. The majority of participants also consumed most of the porridge intended for the household. In sum, LNS was acceptable and used regularly. Larger studies to evaluate physical and psychosocial consequences of LNS during pregnancy among HIV-infected women are warranted.

A Rocky Road: Bladder Stones in the Augmented Exstrophy-Epispadias Complex Patient.

OBJECTIVES: To determine the rate of stone formation amongst patients of the exstrophy-epispadias complex with augmentation cystoplasty. We hypothesize that bowel segment choice influences the rate of stone formation after bladder augmentation and the rate of complications from bladder stone surgery. METHODS: An IRB approved institutional database of 1512 exstrophy-epispadias patients was reviewed retrospectively. Patients that had a history of bladder augmentation and were seen at our institution between 2003 and 2023 were included. RESULTS: Out of 259 patients, bladder stones developed in 21.6% (56), of which the bowel segment used was colon in 147 patients and ileum in 100. Stones formed in 19% of colon augments compared to 29% ileal augments, however this was not statistically significant (p=0.07). The most common primary stone component was dahllite, followed by struvite for all augments. The median time to stone treatment after augmentation was 4.14 years (0.75-31). 74% of patients had a recurrence that required a second surgery. The median time from first to second surgery and second to third surgery was 1.4 years and 2.22 years, respectively. Bladder stone surgery complications occurred in 14% of patients, vesicocutaneous fistula being the most common, and complications did not differ by augment type. Median follow up after first stone intervention was 6.07 years (0-19.5). CONCLUSION: The treatment of bladder stones in the exstrophy-epispadias complex remains challenging. Interventions to prevent recurrence are crucial as the majority of patients will require two or more stone surgeries in their lifetime.

The Treatment of Genitoperineal Hidradenitis Suppurativa: A Review of the Literature.

Hidradenitis suppurativa is a chronic inflammatory condition affecting the axilla, genitals, perineum, and perianal regions. The pathophysiology of hidradenitis suppurativa is complex and requires a multidisciplinary approach to treatment involving medical and surgical management when indicated. We describe our multidisciplinary protocol for treatment, which includes rheumatology-monitored immunotherapy, medical management, wide surgical resection, wound care, and reconstruction. The multidisciplinary care team includes rheumatology, wound care, and reconstructive urologic surgery. Surgical management includes wide local surgical resection, negative pressure dressing, delayed reconstruction, and perioperative immunotherapy. Multimodal treatment with surgical, medical, wound, and immunotherapy care is vital to successful treatment.

An efficient protocol for in vivo labeling of proliferating epithelial cells.

The study of organogenesis, tissue-homeostasis and regeneration requires the precise assessment of in vivo cell proliferation. To this end a host of methods have been developed to detect and quantify DNA synthesis in proliferating cells. These include cell labeling with various nucleotide analogues and fluorescence reporter-based animal models with each method presenting its idiosyncratic shortcomings. Quantitative assessment of epithelial cell turnover has been partly hampered due to their variable and limited in vivo accessibility and the requirement for harsher isolation procedures to procure single cells for FACS analysis. Here, we report a reliable protocol to study in vivo cell proliferation of epithelial cells in mice by repeatedly injecting EdU intravenously for an extended 12-day period. EdU incorporation was quantitated ex vivo by FACS after tissue dissociation in order to obtain single epithelial cell suspensions. As a lead population, we analyzed thymic epithelial cells (TECs), where we were able to label compartmentalized TEC subsets to saturation without apparent toxic effects on the thymus architecture or stress-sensitive TEC lineage differentiation. The data is in concordance with the prevailing model of medullary TEC terminal differentiation that includes the post-Aire stage. The same protocol was successfully applied to epithelial cells of various other organs - skin, lymph node, kidney and small intestine - tissues with widely varying frequencies and rates of proliferating epithelial cells.

Development and evaluation of ß-galactosidase-sensitive antibody-drug conjugates.

The selective destruction of tumour cells while sparing healthy tissues is one of the main challenges in cancer therapy. Antibody-drug conjugates (ADCs) are arguably the most rapidly expanding class of targeted cancer therapies. Efficient drug conjugation and release technologies are essential for the development of these new therapeutic agents. In response to the ever-increasing demand for efficient drug release systems, we have developed a new class of ß-galactosidase-cleavable linkers for ADCs. Within this framework, novel payloads comprising a galactoside linker, the monomethyl auristatin E (MMAE) and cysteine-reactive groups were synthesized, conjugated with trastuzumab and evaluated both in vitro and in vivo. The ADCs with galactoside linkers demonstrated superior therapeutic efficacy in mice compared to the marketed trastuzumab emtansine used for the treatment of breast cancer.

Design and challenges of a randomized clinical trial of medical expulsive therapy (tamsulosin) for urolithiasis in the emergency department.

Urolithiasis or urinary stone disease has been estimated to affect about 1 in 11 Americans. Patients with urinary stone disease commonly present to the emergency department for management of their acute pain. In addition to providing analgesia, administration of drug (medical expulsive therapy) is often prescribed to assist passage of the urinary stone. In this methodology paper, we describe the design of a prospective, multi-center, randomized, double-blind placebo controlled clinical trial of the alpha-adrenergic blocker, tamsulosin, to evaluate its effectiveness as medical expulsive therapy. In addition, we describe the unique challenges of conducting a trial of this type within the setting of the emergency department.

Tick saliva represses innate immunity and cutaneous inflammation in a murine model of Lyme disease.

Lyme borreliosis is an arthropod-borne disease transmitted by the Ixodes tick. This spirochetal infection is first characterized by a local cutaneous inflammation, the erythema migrans. The skin constitutes a key interface in the development of the disease. During Borrelia inoculation, tick saliva affects the innate and adaptive immunity of the vertebrate host skin. Some key mediators of innate immunity such as antimicrobial peptides (cathelicidin and defensin families) have been identified as important initiators of skin inflammation. We analyzed the role of tick saliva on integumental innate immunity using different protocols of Borrelia infection, via syringe or direct tick transmission. When syringe inoculation was used, Borrelia triggered skin inflammation with induction of CRAMP, the mouse cathelicidin, and tumor necrosis factor-alpha. However, when Borrelia was transmitted directly via the tick, we observed a significant repression of inflammatory genes, suggesting a critical role of tick saliva in skin innate immunity. For all the protocols tested, a peak of intense Borrelia multiplication occurred in the skin between days 5 and 15, before bacterial dissemination to target organs. We conclude that Borrelia pathogens specifically use the tick saliva to facilitate their transmission to the host and that the skin constitutes an essential interface in the development of Lyme disease.