Affect, Values and Problems Assessing Decision-Making Capacity.

The dominant approach to assessing decision-making capacity in medicine focuses on determining the extent to which individuals possess certain core cognitive abilities. Critics have argued that this model delivers the wrong verdict in certain cases where patient values that are the product of mental disorder or disordered affective states undermine decision-making without undermining cognition. I argue for a re-conceptualization of what it is to possess the capacity to make medical treatment decisions. It is, I argue, the ability to track one's own personal interests at least as well as most people can. Using this idea, I demonstrate that it is possible to craft a solution for the problem cases-one that neither alters existing criteria in dangerous ways (e.g. does not open the door to various kinds of abuse) nor violates the spirit of widely accepted ethical constraints on decision-making assessment.

Plant height shapes hydraulic architecture but does not predict metaxylem area under drought in Sorghum bicolor.

Climate change-induced variations in temperature and precipitation negatively impact plant growth and development. To ensure future food quality and availability, a critical need exists to identify morphological and physiological responses that confer drought tolerance in agro-economically important crop plants throughout all growth stages. In this study, two Sorghum bicolor accessions that differ in their pre-flowering responses to drought were exposed to repeated cycles of drying and rewatering. Morphological, physiological, and histological traits were measured across both juvenile and adult developmental stages. Our results demonstrate that plant height is not predictive of metaxylem area but does influence the hydraulic path and water management in an accession-specific manner. Further, when drought-responsive changes to the plant architecture are unable to compensate for the hydraulic risk associated with prolonged drought exposure, tight control of stomatal aperture is crucial to further mitigate hydraulic damage and prevent xylem embolism.

Multi-Scalar Data Integration Links Glomerular Angiopoietin-Tie Signaling Pathway Activation With Progression of Diabetic Kidney Disease.

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease (ESKD). Prognostic biomarkers reflective of underlying molecular mechanisms are critically needed for effective management of DKD. A three-marker panel was derived from a proteomics analysis of plasma samples by an unbiased machine learning approach from participants (N = 58) in the Clinical Phenotyping and Resource Biobank study. In combination with standard clinical parameters, this panel improved prediction of the composite outcome of ESKD or a 40% decline in glomerular filtration rate. The panel was validated in an independent group (N = 68), who also had kidney transcriptomic profiles. One marker, plasma angiopoietin 2 (ANGPT2), was significantly associated with outcomes in cohorts from the Cardiovascular Health Study (N = 3,183) and the Chinese Cohort Study of Chronic Kidney Disease (N = 210). Glomerular transcriptional angiopoietin/Tie (ANG-TIE) pathway scores, derived from the expression of 154 ANG-TIE signaling mediators, correlated positively with plasma ANGPT2 levels and kidney outcomes. Higher receptor expression in glomeruli and higher ANG-TIE pathway scores in endothelial cells corroborated potential functional effects in the kidney from elevated plasma ANGPT2 levels. Our work suggests that ANGPT2 is a promising prognostic endothelial biomarker with likely functional impact on glomerular pathogenesis in DKD.

The Overdose Crisis and Using Alone: Perspectives of People Who Use Drugs in Rural and Semi-Urban Areas of British Columbia.

Background: A significant rise in the rate of overdose deaths in British Columbia (BC), driven by fentanyl contamination of the illicit drug supply, led to the declaration of a public health emergency in 2016. Those at greatest risk of death are people who use alone. This community-based participatory action research study based in the Fraser East region of BC study aimed to overview underlying factors that contribute to unwitnessed overdoses in semi-urban and rural settings. Methods: This descriptive study used a community-based participatory action research model with peer research associates (PRAs) involved at various research stages. In total, 22 interviews were conducted with participants aged 19 and over who used illicit drugs in the Fraser East since the start of the public health emergency in 2016. A collaborative data analysis approach was taken for data interpretation, and content analysis was performed to explore themes surrounding using alone. Results: Among people who use drugs (PWUD), using alone was found to be influenced by (a) the availability of drugs and personal funds, (b) personal safety, (c) stigma and shame, (d) protecting privacy, (e) mental health conditions and addiction, and (f) the lack of engagement with harm reduction services. At times, using alone was due to unforeseen, episode-specific situations. Conclusion: A multi-dimentional and context-specific approach is needed in overdose prevention and response for people who use drugs alone. There is need for enhanced approaches that address or include support services for families to reduce stigma and isolation of those at risk of an overdose.

Sonic Hedgehog acts as a macrophage chemoattractant during regeneration of the gastric epithelium.

Sonic Hedgehog (Shh), secreted from gastric parietal cells, contributes to the regeneration of the epithelium. The recruitment of macrophages plays a central role in the regenerative process. The mechanism that regulates macrophage recruitment in response to gastric injury is largely unknown. Here we tested the hypothesis that Shh stimulates macrophage chemotaxis to the injured epithelium and contributes to gastric regeneration. A mouse model expressing a myeloid cell-specific deletion of Smoothened (LysMcre/+;Smof/f) was generated using transgenic mice bearing loxP sites flanking the Smo gene (Smo loxP) and mice expressing a Cre recombinase transgene from the Lysozyme M locus (LysMCre). Acetic acid injury was induced in the stomachs of both control and LysMcre/+;Smof/f (SmoKO) mice and gastric epithelial regeneration and macrophage recruitment analyzed over a period of 7 days post-injury. Bone marrow-derived macrophages (BM-Mø) were collected from control and SmoKO mice. Human-derived gastric organoid/macrophage co-cultures were established, and macrophage chemotaxis measured. Compared to control mice, SmoKO animals exhibited inhibition of ulcer repair and normal epithelial regeneration, which correlated with decreased macrophage infiltration at the site of injury. Bone marrow chimera experiments using SmoKO donor cells showed that control chimera mice transplanted with SmoKO bone marrow donor cells exhibited a loss of ulcer repair, and transplantation of control bone marrow donor cells to SmoKO mice rescued epithelial cell regeneration. Histamine-stimulated Shh secretion in human organoid/macrophage co-cultures resulted in macrophage migration toward the gastric epithelium, a response that was blocked with Smo inhibitor Vismodegib. Shh-induced macrophage migration was mediated by AKT signaling. In conclusion, Shh signaling acts as a macrophage chemoattractant via a Smo-dependent mechanism during gastric epithelial regeneration in response to injury.

Ontogeny and function of the circadian clock in intestinal organoids.

Circadian rhythms regulate diverse aspects of gastrointestinal physiology ranging from the composition of microbiota to motility. However, development of the intestinal circadian clock and detailed mechanisms regulating circadian physiology of the intestine remain largely unknown. In this report, we show that both pluripotent stem cell-derived human intestinal organoids engrafted into mice and patient-derived human intestinal enteroids possess circadian rhythms and demonstrate circadian phase-dependent necrotic cell death responses to Clostridium difficile toxin B (TcdB). Intriguingly, mouse and human enteroids demonstrate anti-phasic necrotic cell death responses to TcdB. RNA-Seq analysis shows that ~3-10% of the detectable transcripts are rhythmically expressed in mouse and human enteroids. Remarkably, we observe anti-phasic gene expression of Rac1, a small GTPase directly inactivated by TcdB, between mouse and human enteroids, and disruption of Rac1 abolishes clock-dependent necrotic cell death responses. Our findings uncover robust functions of circadian rhythms regulating clock-controlled genes in both mouse and human enteroids governing organism-specific, circadian phase-dependent necrotic cell death responses, and lay a foundation for human organ- and disease-specific investigation of clock functions using human organoids for translational applications.

Disruption of Her2-Induced PD-L1 Inhibits Tumor Cell Immune Evasion in Patient-Derived Gastric Cancer Organoids.

(1) Background: The expression of programmed death-ligand 1 (PD-L1), which interacts with programmed cell death protein 1 (PD-1) on cytotoxic T lymphocytes (CTLs), enables tumors to escape immunosurveillance. The PD-1/PD-L1 interaction results in the inhibition of CTL proliferation, and effector function, thus promoting tumor cell evasion from immunosurveillance and cancer persistence. Despite 40% of gastric cancer patients exhibiting PD-L1 expression, only a small subset of patients responds to immunotherapy. Human epidermal growth factor receptor2 (HER2) is one of the critical regulators of several solid tumors, including metastatic gastric cancer. Although half of PD-L1-positive gastric tumors co-express HER2, crosstalk between HER2 and PD-1/PD-L1 in gastric cancer remains undetermined. (2) Methods: Human gastric cancer organoids (huTGOs) were generated from biopsied or resected tissues and co-cultured with CTLs and myeloid-derived suppressor cells (MDSCs). Digital Spatial Profiling (DSP) was performed on FFPE tissue microarrays of numerous gastric cancer patients to examine the protein expression of immune markers. (3) Results: Knockdown of HER2 in PD-L1/HER2-positive huTGOs led to a concomitant decrease in PD-L1 expression. Similarly, in huTGOs/immune cell co-cultures, PD-L1 expression decreased in huTGOs and was correlated with an increase in CTL proliferation which enhanced huTGO death. Treatment with Nivolumab exhibited similar effects. However, a combinatorial treatment with Mubritinib and Nivolumab was unable to inhibit HER2 expression in co-cultures containing MDSCs. (4) Conclusions: Our study suggested that co-expression of HER2 and PD-L1 may contribute to tumor cell immune evasion. In addition, autologous organoid/immune cell co-cultures can be exploited to effectively screen responses to a combination of anti-HER2 and immunotherapy to tailor treatment for gastric cancer patients.

Theory Without Theories: Well-Being, Ethics, and Medicine.

Medical ethics would be better if people were taught to think more clearly about well-being or (what I take to be the same thing) the concept of what is good for a person. Yet for a variety of reasons, bioethicists have generally paid little attention to this concept. Here, I argue, first, that focusing on general theories of welfare is not useful for practical medical ethics. I argue, second, for what I call the "theory-without-theories approach" to welfare in practical contexts. The first element of this approach is a focus on examining important and relatively uncontroversial constituents of welfare as opposed to general theories. The second key element is a framework for thinking about choice in relation to welfare, a framework I refer to as "the mild objectivity framework." I conclude with illustrations of the way in which the "theory without theories approach" can improve thinking in medicine.

Substance use and overdose risk: documenting the perspectives of formerly incarcerated persons in the Fraser East region of BC.

BACKGROUND: The relationship between incarceration and risk of overdose has been well-documented in the literature, but few studies document the perspectives of persons at risk of overdose who were incarcerated. This sub-inquiry aimed to understand the experiences of persons with a history of substance use and incarceration in the Fraser East region of BC and how involvement with the criminal justice system affected their drug use and perceived risk of overdose. METHODS: The Fraser East Overdose Response project utilized a community-based participatory action approach that included peer researchers with lived experience in all parts of the research process. This qualitative pilot study aimed to better understand individuals at risk of an unwitnessed overdose in order to prevent deaths and identify effective local responses. A snowball sampling technique was used to recruit persons aged 19 and over who used illicit drugs over the past 3 years in the Fraser East since 2016. In total, 22 participants were interviewed. Of these, 13 participants identified a history of incarceration. Interviews were analyzed using a framework analysis approach. RESULTS: The perspectives that participants shared revealed that impacts from incarceration are influenced by policies but also highly individualized. Our inquiry found three broader themes, within which were situated differing and sometimes conflicting interpretations and experiences of systemic environments: (1) incarceration was associated with harms and was perceived to increase risk of overdose following release, (2) incarceration was perceived to have limited impact on substance use and overdose risk, and (3) incarceration was associated with a perceived reduction of substance use and overdose risk. CONCLUSIONS: Understanding the complexities of the perceptions of those with lived experience of substance use and incarceration is of importance to better inform interventions in this population. The existing knowledge base urgently requires further inquiry into the intersections between qualitative perspectives, environments and policies, and quantitative outcomes of overdose vís-a-vís correctional institution.

Hedgehog transcriptional effector GLI mediates mTOR-Induced PD-L1 expression in gastric cancer organoids.

Tumors evade immune surveillance by expressing Programmed Death-Ligand 1 (PD-L1), subsequently inhibiting CD8+ cytotoxic T lymphocyte function. Response of gastric cancer to immunotherapy is relatively low. Our laboratory has reported that Helicobacter pylori-induced PD-L1 expression within the gastric epithelium is mediated by the Hedgehog (Hh) signaling pathway. The PI3K/AKT/mTOR pathway is activated in gastric cancer and may have immunomodulatory potential. We hypothesize that Hh signaling mediates mTOR-induced PD-L1 expression. Patient-derived organoids (PDOs) were generated from gastric biopsies and resected tumor tissues. Autologous organoid/immune cell co-cultures were used to study the immunosuppressive function of MDSCs. NanoString Digital Spatial Profiling (DSP) of immune-related protein markers using FFPE slide-mounted tissues from gastric cancer patients was performed. DSP analysis showed infiltration of immunosuppressive MDSCs expressing Arg1, CD66b, VISTA and IDO1 within cancer tissues. Orthotopic transplantation of patient derived organoids (PDOs) resulted in the engraftment of organoids and the development of histology similar to that observed in the patient's tumor tissue. PDO/immune cell co-cultures revealed that PD-L1-expressing organoids were unresponsive to nivolumab in vitro in the presence of PMN-MDSCs. Depletion of PMN-MDSCs within these co-cultures sensitized the organoids to anti-PD-1/PD-L1-induced cancer cell death. Rapamycin decreased phosphorylated S6K, Gli2 and PD-L1 expression in PDO/immune cell co-cultures. Transcriptional regulation of PD-L1 by GLI1 and GLI2 was blocked by rapamycin. In conclusion, the PDO/immune cell co-cultures may be used to study immunosuppressive MDSC function within the gastric tumor microenvironment. The mTOR signaling pathway mediates GLI-induced PD-L1 expression in gastric cancer.

Integration of high-density genetic mapping with transcriptome analysis uncovers numerous agronomic QTL and reveals candidate genes for the control of tillering in sorghum.

Phenotypes such as branching, photoperiod sensitivity, and height were modified during plant domestication and crop improvement. Here, we perform quantitative trait locus (QTL) mapping of these and other agronomic traits in a recombinant inbred line (RIL) population derived from an interspecific cross between Sorghum propinquum and Sorghum bicolor inbred Tx7000. Using low-coverage Illumina sequencing and a bin-mapping approach, we generated ∼1920 bin markers spanning ∼875 cM. Phenotyping data were collected and analyzed from two field locations and one greenhouse experiment for six agronomic traits, thereby identifying a total of 30 QTL. Many of these QTL were penetrant across environments and co-mapped with major QTL identified in other studies. Other QTL uncovered new genomic regions associated with these traits, and some of these were environment-specific in their action. To further dissect the genetic underpinnings of tillering, we complemented QTL analysis with transcriptomics, identifying 6189 genes that were differentially expressed during tiller bud elongation. We identified genes such as Dormancy Associated Protein 1 (DRM1) in addition to various transcription factors that are differentially expressed in comparisons of dormant to elongating tiller buds and lie within tillering QTL, suggesting that these genes are key regulators of tiller elongation in sorghum. Our study demonstrates the usefulness of this RIL population in detecting domestication and improvement-associated genes in sorghum, thus providing a valuable resource for genetic investigation and improvement to the sorghum community.

Cutaneous Disease as a Rare Presentation of Follicular Lymphoma Progression.

Follicular lymphoma, the third most common lymphoid malignancy, is considered indolent but incurable non-Hodgkin lymphoma. Isolated cutaneous relapse from follicular lymphoma is very uncommon, and very few cases have been reported in the literature. In this article, we present a case of an adult patient with a history of treated follicular lymphoma who presented with a skin lesion on his face and scalp. Further workup, including biopsy, led to the diagnosis of relapsed follicular lymphoma with no progression of disease elsewhere. We reviewed cases of follicular lymphoma, which relapsed with isolated cutaneous involvement. Treatment options for relapsed follicular lymphoma include observation, anti-CD 20 antibody alone, or in combination with chemotherapy, radio-immunotherapy, and stem cell transplantation in selected patients. Increased awareness of disease evolution and prompt diagnosis of this form of relapse from follicular lymphoma will improve the effectiveness and outcome of its management.

Differences in microbial community response to nitrogen fertilization result in unique enzyme shifts between arbuscular and ectomycorrhizal-dominated soils.

While the effect of nitrogen (N) deposition on belowground carbon (C) cycling varies, emerging evidence shows that forest soils dominated by trees that associate with ectomycorrhizal fungi (ECM) store more C than soils dominated by trees that associate with arbuscular mycorrhizae (AM) with increasing N deposition. We hypothesized that this is due to unique nutrient cycling responses to N between AM and ECM-dominated soils. ECM trees primarily obtain N through fungal mining of soil organic matter subsidized by root-C. As such, we expected the largest N-induced responses of C and N cycling to occur in ECM rhizospheres and be driven by fungi. Conversely, as AM trees rely on bacterial scavengers in bulk soils to cycle N, we predicted the largest AM responses to be driven by shifts in bacteria and occur in bulk soils. To test this hypothesis, we measured microbial community composition, metatranscriptome profiles, and extracellular enzyme activity in bulk, rhizosphere, and organic horizon (OH) soils in AM and ECM-dominated soils at Bear Brook Watershed in Maine, USA. After 27 years of N fertilization, fungal community composition shifted across ECM soils, but bacterial communities shifted across AM soils. These shifts were mirrored by enhanced C relative to N mining enzyme activities in both mycorrhizal types, but this occurred in different soil fractions. In ECM stands these shifts occurred in rhizosphere soils, but in AM stands they occurred in bulk soils. Additionally, ECM OH soils exhibited the opposite response with declines in C relative to N mining. As rhizosphere soils account for only a small portion of total soil volume relative to bulk soils, coupled with declines in C to N enzyme activity in ECM OH soils, we posit that this may partly explain why ECM soils store more C than AM soils as N inputs increase.

Further Reflections: Surrogate Decisionmaking When Significant Mental Capacities are Retained.

Mackenzie Graham has made an important contribution to the literature on decisionmaking for patients with disorders of consciousness. He argues, and I agree, that decisions for unresponsive patients who are known to retain some degree of covert awareness ought to focus on current interests, since such patients likely retain the kinds of mental capacities that in ordinary life command our current respect and attention. If he is right, then it is not appropriate to make decisions for such patients by appealing to the values they had in the past, either the values expressed in an advance directive or the values recalled by a surrogate. There are two things I wish to add to the discussion. My first point is somewhat critical, for although I agree with his general conclusion about how, ideally, such decisions should be approached, I remain skeptical about whether his conclusion offers decisionmakers real practical help. The problem with these cases is that the evidence we have about the nature of the patient's current interests is minimal or nonexistent. However-and this is important-Graham's conclusion will be extremely relevant if in the future, our ability to communicate with such patients improves, as I hope it will. This leads to my second point. Graham's conclusion illustrates a more general problem with our standard framework for decisionmaking for previously competent patients, a problem that has not been adequately recognized. So, in what follows, I explain the problem I see and offer some brief thoughts about solutions.

Evolutionary Dynamics of Transposable Elements Following a Shared Polyploidization Event in the Tribe Andropogoneae.

Both polyploidization and transposable element (TE) activity are known to be major drivers of plant genome evolution. Here, we utilize the Zea-Tripsacum clade to investigate TE activity and accumulation after a shared polyploidization event. Comparisons of TE evolutionary dynamics in various Zea and Tripsacum species, in addition to two closely related diploid species, Urelytrum digitatum and Sorghum bicolor, revealed variation in repeat content among all taxa included in the study. The repeat composition of Urelytrum is more similar to that of Zea and Tripsacum compared to Sorghum, despite the similarity in genome size with the latter. Although LTR-retrotransposons were abundant in all species, we observed an expansion of the copia superfamily, specifically in Z. mays and T. dactyloides, species that have adapted to more temperate environments. Additional analyses of the genomic distribution of these retroelements provided evidence of biased insertions near genes involved in various biological processes including plant development, defense, and macromolecule biosynthesis. Specifically, copia insertions in Zea and T. dactyloides were significantly enriched near genes involved in abiotic stress response, suggesting independent evolution post Zea-Tripsacum divergence. The lack of copia insertions near the orthologous genes in S. bicolor suggests that duplicate gene copies generated during polyploidization may offer novel neutral sites for TEs to insert, thereby providing an avenue for subfunctionalization via TE insertional mutagenesis.

Phenotypic and physiological responses to salt exposure in Sorghum reveal diversity among domesticated landraces.

PREMISE: Soil salinity negatively impacts plant function, development, and yield. To overcome this impediment to agricultural productivity, variation in morphological and physiological response to salinity among genotypes of important crops should be explored. Sorghum bicolor is a staple crop that has adapted to a variety of environmental conditions and contains a significant amount of standing genetic diversity, making it an exemplary species to study variation in salinity tolerance. METHODS: Twenty-one diverse Sorghum accessions were treated with nonsaline water or 75 mM sodium chloride. Salinity tolerance was assessed via changes in biomass between control and salt-treated individuals. Accessions were first rank-ordered for salinity tolerance, and then individuals spanning a wide range of responses were analyzed for foliar proline and ion accumulation. Tolerance rankings were then overlaid on a neighbor-joining tree. RESULTS: We found that, while proline is often a good indicator of osmotic adjustment and is historically associated with increased salt tolerance in many species, proline accumulation in sorghum reflects a stress response injury rather than acclimation. When combining ion profiles with stress tolerance indices, the variation observed in tolerance was not a sole result of Na+ accumulation, but rather reflected accession-specific mechanisms. CONCLUSIONS: We identified significant variation in salinity tolerance among Sorghum accessions that may be a result of the domestication history of Sorghum. When we compared our results with known phylogenetic relationships within sorghum, the most parsimonious explanation for our findings is that salinity tolerance was acquired early during domestication and subsequently lost in accessions growing in areas varying in soil salinity.

Tissue Responses to Shiga Toxin in Human Intestinal Organoids.

BACKGROUND & AIMS: Shiga toxin (Stx)-producing Escherichia coli (eg, O157:H7) infection produces bloody diarrhea, while Stx inhibits protein synthesis and causes the life-threatening systemic complication of hemolytic uremic syndrome. The murine intestinal tract is resistant to O157:H7 and Stx, and human cells in culture fail to model the complex tissue responses to intestinal injury. We used genetically identical, human stem cell-derived intestinal tissues of varying complexity to study Stx toxicity in vitro and in vivo. METHODS: In vitro susceptibility to apical or basolateral exposure to Stx was assessed using human intestinal organoids (HIOs) derived from embryonic stem cells, or enteroids derived from multipotent intestinal stem cells. HIOs contain a lumen, with a single layer of differentiated epithelium surrounded by mesenchymal cells. Enteroids only contain epithelium. In vivo susceptibility was assessed using HIOs, with or without an enteric nervous system, transplanted into mice. RESULTS: Stx induced necrosis and apoptotic death in both epithelial and mesenchymal cells. Responses that require protein synthesis (cellular proliferation and wound repair) also were observed. Epithelial barrier function was maintained even after epithelial cell death was seen, and apical to basolateral translocation of Stx was seen. Tissue cross-talk, in which mesenchymal cell damage caused epithelial cell damage, was observed. Stx induced mesenchymal expression of the epithelial marker E-cadherin, the initial step in mesenchymal-epithelial transition. In vivo responses of HIO transplants injected with Stx mirrored those seen in vitro. CONCLUSIONS: Intestinal tissue responses to protein synthesis inhibition by Stx are complex. Organoid models allow for an unprecedented examination of human tissue responses to a deadly toxin.

The regulatory landscape of a core maize domestication module controlling bud dormancy and growth repression.

Many domesticated crop plants have been bred for increased apical dominance, displaying greatly reduced axillary branching compared to their wild ancestors. In maize, this was achieved through selection for a gain-of-function allele of the TCP transcription factor teosinte branched1 (tb1). The mechanism for how a dominant Tb1 allele increased apical dominance, is unknown. Through ChIP seq, RNA seq, hormone and sugar measurements on 1 mm axillary bud tissue, we identify the genetic pathways putatively regulated by TB1. These include pathways regulating phytohormones such as gibberellins, abscisic acid and jasmonic acid, but surprisingly, not auxin. In addition, metabolites involved in sugar sensing such as trehalose 6-phosphate were increased. This suggests that TB1 induces bud suppression through the production of inhibitory phytohormones and by reducing sugar levels and energy balance. Interestingly, TB1 also putatively targets several other domestication loci, including teosinte glume architecture1, prol1.1/grassy tillers1, as well as itself. This places tb1 on top of the domestication hierarchy, demonstrating its critical importance during the domestication of maize from teosinte.

Increased Programmed Death-Ligand 1 is an Early Epithelial Cell Response to Helicobacter pylori Infection.

Helicobacter pylori (H. pylori) is the major risk factor for the development of gastric cancer. Our laboratory has reported that the Sonic Hedgehog (Shh) signaling pathway is an early response to infection that is fundamental to the initiation of H. pylori-induced gastritis. H. pylori also induces programmed death ligand 1 (PD-L1) expression on gastric epithelial cells, yet the mechanism is unknown. We hypothesize that H. pylori-induced PD-L1 expression within the gastric epithelium is mediated by the Shh signaling pathway during infection. To identify the role of Shh signaling as a mediator of H. pylori-induced PD-L1 expression, human gastric organoids generated from either induced pluripotent stem cells (HGOs) or tissue (huFGOs) were microinjected with bacteria and treated with Hedgehog/Gli inhibitor GANT61. Gastric epithelial monolayers generated from the huFGOs were also infected with H. pylori and treated with GANT61 to study the role of Hedgehog signaling as a mediator of induced PD-1 expression. A patient-derived organoid/autologous immune cell co-culture system infected with H. pylori and treated with PD-1 inhibitor (PD-1Inh) was developed to study the protective mechanism of PD-L1 in response to bacterial infection. H. pylori significantly increased PD-L1 expression in organoid cultures 48 hours post-infection when compared to uninfected controls. The mechanism was cytotoxic associated gene A (CagA) dependent. This response was blocked by pretreatment with GANT61. Anti-PD-L1 treatment of H. pylori infected huFGOs, co-cultured with autologous patient cytotoxic T lymphocytes and dendritic cells, induced organoid death. H. pylori-induced PD-L1 expression is mediated by the Shh signaling pathway within the gastric epithelium. Cells infected with H. pylori that express PD-L1 may be protected from the immune response, creating premalignant lesions progressing to gastric cancer.

Soluble ST2 and Galectin-3 and Progression of CKD.

INTRODUCTION: Cardiac biomarkers soluble ST2 (sST2) and galectin-3 may reflect cardiac inflammation and fibrosis. It is plausible that these mechanisms may also contribute to the progression of kidney disease. We examined associations of sST2 and galectin-3 with kidney function decline in participants with chronic kidney disease (CKD). METHODS: This was a pooled analysis of 2 longitudinal cohorts of participants with CKD: the Clinical Phenotyping and Resource Biobank (C-PROBE) study and the Seattle Kidney Study (SKS). We measured circulating concentrations of sST2 and galectin-3 at baseline. Our primary outcome was progression to estimated glomerular filtration rate (eGFR) <15 ml/min per 1.73 m2 or end-stage renal disease (ESRD). We used competing risk Cox regression models to study the association of sST2 and galectin-3 with CKD progression, adjusting for demographics, kidney function, and comorbidity. RESULTS: Among the 841 participants in the pooled cohort, baseline eGFR was 51 ± 27 ml/min per 1.73 m2 and median urine albumin-to-creatinine ratio (UACR) was 141 (interquartile range = 15-736) mg/g. Participants with higher sST2 and galectin-3 were more likely to be older, to have heart failure and diabetes, and to have lower eGFR. Adjusting for demographics, kidney function, and comorbidity, every doubling of sST2 was not associated with progression to eGFR <15 ml/min per 1.73 m2 or ESRD (adjusted hazard ratio 1.02, 95% confidence interval = 0.76-1.38). Every doubling of galectin-3 was significantly associated with a 38% (adjusted hazard ratio = 1.35, 95% confidence interval = 1.01-1.80) increased risk of progression to eGFR <15 ml/min per 1.73 m2 or ESRD. CONCLUSION: Higher concentrations of the cardiac biomarker galectin-3 may be associated with progression of CKD, highlighting potential novel mechanisms that may contribute to the progression of kidney disease.