Biology subjects

Awad, W.

Publications and source records attributed to Awad, W..

5 recordsLinked to original sources

bioRxiv2026

Biodegradable Architected Stents for Endoscopic Internal Drainage

Postoperative gastric leak after bariatric surgery is a serious complication associated with prolonged treatment, repeated interventions, and substantial morbidity. Endoscopic internal drainage using double pigtail stents is widely adopted. However, current stents, originally designed for biliary use and often based on simple cylindrical geometries, are not optimized for post-bariatric gastric leak anatomy, mechanical support, or fluid drainage. Here, we present BRIDGE (Biodegradable aRchitected Internal DrainaGE), a stent concept integrating triply periodic minimal surface (TPMS) architectures to control mechanical compliance, kink resistance, and drainage performance. Using computational modeling, mechanical testing, and benchtop flow studies, we evaluate TPMS designs and identify volume fraction as a key parameter balancing flexibility, structural integrity, and hydraulic performance. TPMS-integrated designs tolerated a 7.1-fold smaller bend radius than a commercial stent without kinking and achieved up to a 2-fold increase in drainage. We also developed a stereolithography-printable biodegradable resin and fabricated a prototype lattice-integrated stent. TeaserA biodegradable, 3D-printed stent with an architected lattice design improves flexibility, kink resistance, and abscess drainage while eliminating the need for device removal.

bioengineering↗

bioRxiv2026

Specific targeting of MR1-antigen complexes using nanobodies

T cell receptor mimic (TCRm) antibodies and nanobodies that specifically bind peptide-HLA complexes have great therapeutic potential, as they can target polymorphic HLA on tumour cells furnishing peptides derived from tumour-associated antigens. MR1 is an MHC class-I-like molecule that exhibits limited polymorphism that binds and presents conserved metabolites, such as 5-OP-RU, derived from microbial riboflavin biosynthesis. Whether antibodies targeting such MR1-5-OP-RU complexes can be generated remains unclear. Using yeast display technology and in vitro affinity maturation, a nanobody with high affinity and fine specificity toward MR1-5-OP-RU complex was generated. These nanobodies bind both mouse and human MR1-5-OP-RU and inhibited MAIT cell responses to 5-OP-RU in vitro and in vivo demonstrating therapeutic potential. Moreover, we provide a molecular basis underpinning the fine specificity of these nanobodies, solving the crystal structures of MR1 in complex with either 5-OP-RU or Ac-6-FP. Here, the nanobody co-bound MR1 and 5-OP-RU, akin to a TCRm antibody. Moreover, we engineer bispecific antibodies targeting both MR1-5-OP-RU and CD3, that drive broad T cell killing of bacterially-infected cells as well as tumour cells treated with 5-OP-RU, thereby providing proof-of-principle for targeting the MR1 molecule with with TCRm-based nanobodies. One Sentence SummaryWe report the development of a nanobody targeting MR1-5-OP-RU complex and demonstrate its utility to modulate MAIT cells responses, and as a bispecific engager.

immunology↗

bioRxiv2025

The antigen presenting molecule MR1 binds riboflavin catabolites

Major histocompatibility-complex (MHC) class I-related (MR1) protein presents vitamin B based antigens to Mucosal-Associated Invariant T (MAIT) cells. While microbial riboflavin precursors are well documented MR1 ligands, it is unclear whether host-generated riboflavin catabolites influence MR1-mediated immunity. Here, we report that riboflavin catabolites, including 10-formylmethylflavin (FMF), lumichrome, lumiflavin and alloxazine bind to MR1 with moderate affinity, while riboflavin itself binds weakly. In contrast to the microbial riboflavin antigens which increase MR1 cell surface expression, the riboflavin catabolites moderately reduced cell surface levels of MR1 by stabilizing and retaining MR1 in the endoplasmic reticulum (ER). The riboflavin catabolites appeared to bind to the intracellular MR1 and inhibit MR1 exit from the ER. These riboflavin catabolites also weakly competed with Vit B based Ags for MR1 binding, thereby inhibiting MAIT cell activation. The crystal structures of MR1 complexed with riboflavin, FMF, lumichrome and lumiflavin, show binding of these three-ringed ligands in the A-pocket of MR1. The crystal structure of MR1-lumichrome revealed that lumichrome formed a covalent "flavin bond" with MR1-Lys43 differing from the typical Schiff-base bond of MR1-Lys43-Ag complexes. Collectively, we identified three ring isoalloxazines that can bind MR1 and downregulate cell surface expression levels, suggesting a potential role in dampening MAIT cell immunity.

biochemistry↗

bioRxiv2023

Spatiotemporal development of the human T follicular helper cell response to Influenza vaccination

We profiled blood and draining lymph node (LN) samples from human volunteers after influenza vaccination over two years to define evolution in the T follicular helper cell (TFH) response. We show LN TFH cells expanded in a clonal-manner during the first two weeks after vaccination and persisted within the LN for up to six months. LN and circulating TFH (cTFH) clonotypes overlapped but had distinct kinetics. LN TFH cell phenotypes were heterogeneous and mutable, first differentiating into pre-TFH during the month after vaccination before maturing into GC and IL-10+ TFH cells. TFH expansion, upregulation of glucose metabolism, and redifferentiation into GC TFH cells occurred with faster kinetics after re-vaccination in the second year. We identified several influenza-specific TFH clonal lineages, including multiple responses targeting internal influenza proteins, and show each TFH state is attainable within a lineage. This study demonstrates that human TFH cells form a durable and dynamic multi-tissue network.

immunology↗

bioRxiv2018

Senescent, dysfunctional human cardiac progenitor cells (CPCs) accumulate in the aged heart and elimination of senescent cells enhances CPC activation and cardiomyocyte proliferation in aged mice

Aging leads to increased cellular senescence and is associated with decreased potency of tissue-specific stem/progenitor cells. Here we have done an extensive analysis of cardiac progenitor cells (CPCs) isolated from human subjects with cardiovascular disease (n=119), aged 32-86 years. In aged subjects (>74 years old) over half of CPCs are senescent (p16INK4A, SA-{beta}-gal, DNA damage {gamma}H2AX, telomere length, Senescence-Associated Secretory Phenotype (SASP)), unable to replicate, differentiate, regenerate or restore cardiac function following transplantation into the infarcted heart. SASP factors secreted by senescent CPCs renders otherwise healthy CPCs to senescence. Elimination of senescent CPCs using senolytics abrogates the SASP and its debilitative effect in vitro. Global elimination of senescent cells in aged mice (INK-ATTAC or wildtype mice treated with D+Q senolytics) in vivo activates resident CPCs (0.23{+/-}0.06% vs. 0.01{+/-}0.01% vehicle; p<0.05) and increased the number of small, proliferating Ki67-, EdU-positive cardiomyocytes (0.25{+/-}0.07% vs. 0.03{+/-}0.03% vehicle; p<0.05). Therapeutic approaches that eliminate senescent cells may alleviate cardiac deterioration with aging and rejuvenate the regenerative capacity of the heart.

physiology↗