Biology subjects

Stephenson, S.

Publications and source records attributed to Stephenson, S..

6 recordsLinked to original sources

bioRxiv2024

Urban wastewater contains a functional human antibody repertoire of mucosal origin

Wastewater-based surveillance of human disease offers timely insights to public health, helping to mitigate infectious disease outbreaks and decrease downstream morbidity and mortality. These systems rely on nucleic acid amplification tests for monitoring disease trends, while antibody-based seroprevalence surveys gauge community immunity. However, serological surveys are resource-intensive and subject to potentially long lead times and sampling bias. We identified and characterized a human antibody repertoire, predominantly secretory IgA, isolated from a central wastewater treatment plant and building-scale wastewater collection points. These antibodies partition to the solids fraction and retain immunoaffinity for SARS-CoV-2 and Influenza A virus antigens. This stable pool could enable real-time tracking of correlates of vaccination, infection, and immunity, aiding in establishing population-level thresholds for immune protection and assessing the efficacy of future vaccine campaigns, particularly those that are designed to induce humoral mucosal immunity.

immunology↗

bioRxiv2024

HIGH THROUGHPUT QUANTITATION OF HUMAN NEUTROPHIL RECRUITMENT AND FUNCTIONAL RESPONSES IN AN AIR-BLOOD BARRIER ARRAY

Dysregulated neutrophil recruitment drives many pulmonary diseases, but most preclinical screening methods are unsuited to evaluate pulmonary neutrophilia, limiting progress towards therapeutics. Namely, high throughput therapeutic screening systems typically exclude critical neutrophilic pathophysiology, including blood-to-lung recruitment, dysfunctional activation, and resulting impacts on the air-blood barrier. To meet the conflicting demands of physiological complexity and high throughput, we developed an assay of 96-well Leukocyte recruitment in an Air-Blood Barrier Array (L-ABBA-96) that enables in vivo-like neutrophil recruitment compatible with downstream phenotyping by automated flow cytometry. We modeled acute respiratory distress syndrome (ARDS) with neutrophil recruitment to 20 ng/mL epithelial-side interleukin 8 (IL-8) and found a dose dependent reduction in recruitment with physiologic doses of baricitinib, a JAK1/2 inhibitor recently FDA-approved for severe COVID-19 ARDS. Additionally, neutrophil recruitment to patient-derived cystic fibrosis sputum supernatant induced disease-mimetic recruitment and activation of healthy donor neutrophils and upregulated endothelial e-selectin. Compared to 24-well assays, the L-ABBA-96 reduces required patient sample volumes by 25 times per well and quadruples throughput per plate. Compared to microfluidic assays, the L-ABBA-96 recruits two orders of magnitude more neutrophils per well, enabling downstream flow cytometry and other standard biochemical assays. This novel pairing of high-throughput in vitro modeling of organ-level lung function with parallel high-throughput leukocyte phenotyping substantially advances opportunities for pathophysiological studies, personalized medicine, and drug testing applications.

bioengineering↗

bioRxiv2024

Enforced MYC expression selectively redirects transcriptional programs during human plasma cell differentiation

MYC provides a rheostat linking cell growth and division during plasma cell (PC) differentiation. Precise control of MYC is central to the network controlling differentiation. Deregulation of MYC drives transformation in aggressive B-cell neoplasms and is often accompanied by apoptotic protection conferred by BCL2. We assess how MYC and BCL2 deregulation impacts on the ability of human B-cells to complete PC differentiation. Under permissive conditions for PC differentiation we find such deregulation does not transform cells. While driving loss of normal PC surface phenotype, MYC deregulation has little impact on components of regulatory circuitry controlling B-cell identity. This contrasts with profound impact on initiation of secretory output and secretory reprogramming, coupled to dampening of XBP1 and immunoglobulin gene enhancement and a shift toward distinct metabolic programs. The establishment of this aberrant state depends on MYC homology boxes (MB0 and MBII). Dependence on MBII is profound and resolves to residue W135.

cell biology↗

bioRxiv2022

Endozoicomonas-chlamydiae interactions in cell-associated microbial aggregates of the coral Pocillopora acuta

Corals are associated with a variety of bacteria, which occur in the surface mucus layer, gastrovascular cavity, skeleton, and tissues. Some tissue-associated bacteria form clusters, termed cell-associated microbial aggregates (CAMAs), which are poorly studied. Here, we provide a comprehensive characterization of CAMAs in the coral Pocillopora acuta. Combining imaging techniques, laser capture microdissection, and amplicon and metagenome sequencing we show that CAMAs: (i) are located in the tentacle tips and may be intracellular; (ii) contain Endozoicomonas, Kistimonas (both Gammaproteobacteria), and Simkania (Chlamydiota) bacteria; (iii) Endozoicomonas may provide vitamins to its host and use secretion systems and/or pili for colonization and aggregation; (iv) Endozoicomonas and Simkania occur in distinct, but adjacent, CAMAs; (v) Simkania may rely on acetate and heme provided by neighboring Endozoicomonas. Our study provides detailed insight into coral endosymbionts, which will guide the assessment of their suitability for probiotic approaches to mitigate coral bleaching.

microbiology↗

bioRxiv2022

The effects of acute Methylene Blue administration on cerebral blood flow and metabolism in humans and rats

Methylene Blue (MB) is a brain-penetrating drug with putative neuroprotective, antioxidant and metabolic enhancing effects. In vitro studies suggest that MB enhances mitochondrial complexes activity. However, no study has directly assessed the haemodynamic and metabolic effects of MB in the human brain. We used in vivo neuroimaging to measure the effect of MB on cerebral blood flow (CBF) and brain metabolism in humans and in rats. Two doses of MB (0.5 and 1 mg/kg in humans; 2 and 4 mg/kg in rats; iv) induced reductions in global cerebral blood flow (CBF) in humans (F(1.74, 12.17)5.82, p=0.02) and rats (F(1,5)26.04, p=0.0038). Human cerebral metabolic rate of oxygen (CMRO2) was also significantly reduced (F(1.26, 8.84)8.01, p=0.016), as was the rat cerebral metabolic rate of glucose (CMRglu) (t=2.6(16) p=0.018). This was contrary to our hypothesis that MB will increase CBF and energy metrics. Nevertheless, our results were reproducible across species and dose dependent. One possible explanation is that the concentrations used, although clinically relevant, reflect MBs hormetic effects, i.e., higher concentrations produce inhibitory rather than augmentation effects on metabolism. Additionally, here we used healthy volunteers and healthy rats with normal cerebral metabolism where MBs ability to enhance cerebral metabolism might be limited.

neuroscience↗

bioRxiv2020

Fully Implanted Prostheses for Musculoskeletal Limb Reconstruction after Amputation: An In Vivo Feasibility Study

Previous prostheses for replacing a missing limb following amputation must be worn externally on the body. This limits the extent to which prostheses could physically interface with biological tissues, such as muscles, to enhance functional recovery. The objectives of our study were to (1) test the feasibility of implanting a limb prosthesis, or endoprosthesis, entirely within living skin at the distal end of a residual limb, and (2) identify effective surgical and post-surgical care approaches for implanting endoprostheses in a rabbit model of hindlimb amputation. We iteratively designed, fabricated, and implanted unjointed endoprosthesis prototypes in six New Zealand White rabbits following amputation. In the first three rabbits, the skin failed to heal due to dehiscence along the sutured incision. The skin of the final three subsequent rabbits successfully healed over the endoprotheses. Factors that contributed to successful outcomes included modifying the surgical incision to preserve vasculature; increasing the radii size on the endoprostheses to reduce skin stress; collecting radiographs pre-surgery to match the bone pin size to the medullary canal size; and ensuring post-operative bandage integrity. These results will support future work to test jointed endoprostheses that can be attached to muscles.Competing Interest StatementThe authors have declared no competing interest.View Full Text

bioengineering↗