Cell wall melanin impedes growth of the Cryptococcus neoformans polysaccharide capsule by sequestering calcium.

Cryptococcus neoformans has emerged as a frontrunner among deadly fungal pathogens and is particularly life-threatening for many HIV-infected individuals with compromised immunity. Multiple virulence factors contribute to the growth and survival of C. neoformans within the human host, the two most prominent of which are the polysaccharide capsule and melanin. As both of these features are associated with the cell wall, we were interested to explore possible cooperative or competitive interactions between these two virulence factors. Whereas capsule thickness had no effect on the rate at which cells became melanized, build-up of the melanin pigment layer resulted in a concomitant loss of polysaccharide material, leaving melanized cells with significantly thinner capsules than their nonmelanized counterparts. When melanin was provided exogenously to cells in a transwell culture system we observed a similar inhibition of capsule growth and maintenance. Our results show that melanin sequesters calcium thereby limiting its availability to form divalent bridges between polysaccharide subunits required for outer capsule assembly. The decreased ability of melanized cells to incorporate exported polysaccharide into the growing capsule correlated with the amount of shed polysaccharide, which could have profound negative impacts on the host immune response.

The structure of a C. neoformans polysaccharide motif recognized by protective antibodies: A combined NMR and MD study.

Cryptococcus neoformans is a fungal pathogen responsible for cryptococcosis and cryptococcal meningitis. The C. neoformans' capsular polysaccharide and its shed exopolysaccharide function both as key virulence factors and to protect the fungal cell from phagocytosis. Currently, a glycoconjugate of these polysaccharides is being explored as a vaccine to protect against C. neoformans infection. In this study, NOE and J-coupling values from NMR experiments were consistent with a converged structure of the synthetic decasaccharide, GXM10-Ac3, calculated from MD simulations. GXM10-Ac3 was designed as an extension of glucuronoxylomannan (GXM) polysaccharide motif (M2) which is common in the clinically predominant serotype A strains and is recognized by protective forms of GXM-specific monoclonal antibodies. The M2 motif is a hexasaccharide with a three-residue α-mannan backbone, modified by ß-(1→2)-xyloses (Xyl) on the first two mannoses (Man) and a ß-(1→2)-glucuronic acid (GlcA) on the third Man. Combined NMR and MD analyses reveal that GXM10-Ac3 adopts an extended structure, with Xyl/GlcA branches alternating sides along the α-mannan backbone. O-acetyl esters also alternate sides and are grouped in pairs. MD analysis of a twelve M2-repeating unit polymer supports the notion that the GXM10-Ac3 structure is uniformly represented throughout the polysaccharide. This derived GXM model displays high flexibility while maintaining a structural identity, yielding insights to further explore intermolecular interactions between polysaccharides, interactions with anti-GXM mAbs, and the cryptococcal polysaccharide architecture.

ACP-CapsPred: an explainable computational framework for identification and functional prediction of anticancer peptides based on capsule network.

Cancer is a severe illness that significantly threatens human life and health. Anticancer peptides (ACPs) represent a promising therapeutic strategy for combating cancer. In silico methods enable rapid and accurate identification of ACPs without extensive human and material resources. This study proposes a two-stage computational framework called ACP-CapsPred, which can accurately identify ACPs and characterize their functional activities across different cancer types. ACP-CapsPred integrates a protein language model with evolutionary information and physicochemical properties of peptides, constructing a comprehensive profile of peptides. ACP-CapsPred employs a next-generation neural network, specifically capsule networks, to construct predictive models. Experimental results demonstrate that ACP-CapsPred exhibits satisfactory predictive capabilities in both stages, reaching state-of-the-art performance. In the first stage, ACP-CapsPred achieves accuracies of 80.25% and 95.71%, as well as F1-scores of 79.86% and 95.90%, on benchmark datasets Set 1 and Set 2, respectively. In the second stage, tasked with characterizing the functional activities of ACPs across five selected cancer types, ACP-CapsPred attains an average accuracy of 90.75% and an F1-score of 91.38%. Furthermore, ACP-CapsPred demonstrates excellent interpretability, revealing regions and residues associated with anticancer activity. Consequently, ACP-CapsPred presents a promising solution to expedite the development of ACPs and offers a novel perspective for other biological sequence analyses.

A Liver Capsular Network of Monocyte-Derived Macrophages Restricts Hepatic Dissemination of Intraperitoneal Bacteria by Neutrophil Recruitment.

The liver is positioned at the interface between two routes traversed by pathogens in disseminating infection. Whereas blood-borne pathogens are efficiently cleared in hepatic sinusoids by Kupffer cells (KCs), it is unknown how the liver prevents dissemination of peritoneal pathogens accessing its outer membrane. We report here that the hepatic capsule harbors a contiguous cellular network of liver-resident macrophages phenotypically distinct from KCs. These liver capsular macrophages (LCMs) were replenished in the steady state from blood monocytes, unlike KCs that are embryonically derived and self-renewing. LCM numbers increased after weaning in a microbiota-dependent process. LCMs sensed peritoneal bacteria and promoted neutrophil recruitment to the capsule, and their specific ablation resulted in decreased neutrophil recruitment and increased intrahepatic bacterial burden. Thus, the liver contains two separate and non-overlapping niches occupied by distinct resident macrophage populations mediating immunosurveillance at these two pathogen entry points to the liver.

THItoGene: a deep learning method for predicting spatial transcriptomics from histological images.

Spatial transcriptomics unveils the complex dynamics of cell regulation and transcriptomes, but it is typically cost-prohibitive. Predicting spatial gene expression from histological images via artificial intelligence offers a more affordable option, yet existing methods fall short in extracting deep-level information from pathological images. In this paper, we present THItoGene, a hybrid neural network that utilizes dynamic convolutional and capsule networks to adaptively sense potential molecular signals in histological images for exploring the relationship between high-resolution pathology image phenotypes and regulation of gene expression. A comprehensive benchmark evaluation using datasets from human breast cancer and cutaneous squamous cell carcinoma has demonstrated the superior performance of THItoGene in spatial gene expression prediction. Moreover, THItoGene has demonstrated its capacity to decipher both the spatial context and enrichment signals within specific tissue regions. THItoGene can be freely accessed at https://github.com/yrjia1015/THItoGene.

CapsNet-LDA: predicting lncRNA-disease associations using attention mechanism and capsule network based on multi-view data.

Cumulative studies have shown that many long non-coding RNAs (lncRNAs) are crucial in a number of diseases. Predicting potential lncRNA-disease associations (LDAs) can facilitate disease prevention, diagnosis and treatment. Therefore, it is vital to develop practical computational methods for LDA prediction. In this study, we propose a novel predictor named capsule network (CapsNet)-LDA for LDA prediction. CapsNet-LDA first uses a stacked autoencoder for acquiring the informative low-dimensional representations of the lncRNA-disease pairs under multiple views, then the attention mechanism is leveraged to implement an adaptive allocation of importance weights to them, and they are subsequently processed using a CapsNet-based architecture for predicting LDAs. Different from the conventional convolutional neural networks (CNNs) that have some restrictions with the usage of scalar neurons and pooling operations. the CapsNets use vector neurons instead of scalar neurons that have better robustness for the complex combination of features and they use dynamic routing processes for updating parameters. CapsNet-LDA is superior to other five state-of-the-art models on four benchmark datasets, four perturbed datasets and an independent test set in the comparison experiments, demonstrating that CapsNet-LDA has excellent performance and robustness against perturbation, as well as good generalization ability. The ablation studies verify the effectiveness of some modules of CapsNet-LDA. Moreover, the ability of multi-view data to improve performance is proven. Case studies further indicate that CapsNet-LDA can accurately predict novel LDAs for specific diseases.

A prediction model for blood-brain barrier penetrating peptides based on masked peptide transformers with dynamic routing.

Blood-brain barrier penetrating peptides (BBBPs) are short peptide sequences that possess the ability to traverse the selective blood-brain interface, making them valuable drug candidates or carriers for various payloads. However, the in vivo or in vitro validation of BBBPs is resource-intensive and time-consuming, driving the need for accurate in silico prediction methods. Unfortunately, the scarcity of experimentally validated BBBPs hinders the efficacy of current machine-learning approaches in generating reliable predictions. In this paper, we present DeepB3P3, a novel framework for BBBPs prediction. Our contribution encompasses four key aspects. Firstly, we propose a novel deep learning model consisting of a transformer encoder layer, a convolutional network backbone, and a capsule network classification head. This integrated architecture effectively learns representative features from peptide sequences. Secondly, we introduce masked peptides as a powerful data augmentation technique to compensate for small training set sizes in BBBP prediction. Thirdly, we develop a novel threshold-tuning method to handle imbalanced data by approximating the optimal decision threshold using the training set. Lastly, DeepB3P3 provides an accurate estimation of the uncertainty level associated with each prediction. Through extensive experiments, we demonstrate that DeepB3P3 achieves state-of-the-art accuracy of up to 98.31% on a benchmarking dataset, solidifying its potential as a promising computational tool for the prediction and discovery of BBBPs.

Assembly of Bacterial Capsular Polysaccharides and Exopolysaccharides.

Polysaccharides are dominant features of most bacterial surfaces and are displayed in different formats. Many bacteria produce abundant long-chain capsular polysaccharides, which can maintain a strong association and form a capsule structure enveloping the cell and/or take the form of exopolysaccharides that are mostly secreted into the immediate environment. These polymers afford the producing bacteria protection from a wide range of physical, chemical, and biological stresses, support biofilms, and play critical roles in interactions between bacteria and their immediate environments. Their biological and physical properties also drive a variety of industrial and biomedical applications. Despite the immense variation in capsular polysaccharide and exopolysaccharide structures, patterns are evident in strategies used for their assembly and export. This review describes recent advances in understanding those strategies, based on a wealth of biochemical investigations of select prototypes, supported by complementary insight from expanding structural biology initiatives. This provides a framework to identify and distinguish new systems emanating from genomic studies.

Recruitment of large peritoneal macrophages to capsular fibrosis developed on the liver surface.

Upon injury to Glisson's capsule, mesothelial cells covering the liver surface differentiate into myofibroblasts and participate in capsular fibrosis. In the fibrotic area, infiltrating macrophages are present, but their origin and role in capsular fibrosis remain elusive. In the present study, we examined whether macrophages in the peritoneal cavity migrate to the liver and participate in capsular fibrosis. Capsular fibrosis was induced by intraperitoneal injection of chlorhexidine gluconate. Chlorhexidine gluconate treatment induced disappearance of CD11bHigh F4/80High large peritoneal macrophages from the peritoneal cavity. Transplantation of TIMD4+ large peritoneal macrophages to the mouse peritoneal cavity resulted in their recruitment to the fibrotic area of the liver. Bone marrow-derived monocytes were also recruited to the chlorhexidine gluconate-induced fibrotic area upon their transplantation to the peritoneal cavity. However, bone marrow-derived macrophages, Kupffer cells, peritoneal B cells, and small peritoneal macrophages prepared from chlorhexidine gluconate-treated mice did not exhibit such potential. In the hepatic fibrotic area, peritoneal macrophages lost expression of unique markers (Gata6, Timd4) and increased expression of genes involved in inflammation (Il1b, Il6, Tnf) and extracellular matrix remodeling (Mmp13, Timp1). Depletion of peritoneal macrophages by clodronate liposomes reduced capsular fibrosis. Our data indicate that large peritoneal macrophages are recruited to the injured liver surface and promote capsular fibrosis by inducing inflammation and extracellular matrix remodeling. Modulating the function of peritoneal macrophages might be a new approach for suppressing capsular fibrosis.

Control of resistance against bacteriophage killing by a metabolic regulator in meningitis-associated Escherichia coli.

Ecologically beneficial traits in bacteria are encoded by intrinsic and horizontally acquired genes. However, such traits are not universal, and the highly mosaic nature of bacterial genomes requires control at the transcriptional level to drive these processes. It has emerged that regulatory flexibility is widespread in the Escherichia coli species, whereby preexisting transcription factors can acquire new and unrelated roles in regulating beneficial traits. DsdC is the regulator of D-serine tolerance in E. coli, is essential for D-serine catabolism, and is often encoded by two copies in neonatal meningitis-associated E. coli (NMEC). Here, we reveal that DsdC is a global regulator of transcription in NMEC and does not require D-serine for the control of novel beneficial traits. We show that DsdC binds the chromosome in an unusual manner, with many binding sites arranged in clusters spanning entire operons and within gene coding sequences, such as neuO. Importantly, we identify neuO as the most significantly down-regulated gene in a strain deleted for both dsdC copies, in both the presence and absence of D-serine. NeuO is prophage encoded in several NMEC K1 isolates and mediates capsule O-acetylation but has no effect on attachment to or invasion of human brain endothelial cells. Instead, we demonstrate that NeuO provides resistance against K1 bacteriophage attack and that this critical function is regulated by DsdC. This work highlights how a horizontally acquired enzyme that functions in cell-surface modulation can be controlled by an intrinsic regulator to provide a key ecological benefit to an E. coli pathotype.

Sequestration of gut pathobionts in intraluminal casts, a mechanism to avoid dysregulated T cell activation by pathobionts.

T cells that express the transcription factor RORγ, regulatory (Treg), or conventional (Th17) are strongly influenced by intestinal symbionts. In a genetic approach to identify mechanisms underlying this influence, we performed a screen for microbial genes implicated, in germfree mice monocolonized with Escherichia coli Nissle. The loss of capsule-synthesis genes impaired clonal expansion and differentiation of intestinal RORγ+ T cells. Mechanistic exploration revealed that the capsule-less mutants remained able to induce species-specific immunoglobulin A (IgA) and were highly IgA-coated. They could still trigger myeloid cells, and more effectively damaged epithelial cells in vitro. Unlike wild-type microbes, capsule-less mutants were mostly engulfed in intraluminal casts, large agglomerates composed of myeloid cells extravasated into the gut lumen. We speculate that sequestration in luminal casts of potentially harmful microbes, favored by IgA binding, reduces the immune system's actual exposure, preserving host-microbe equilibrium. The variable immunostimulation by microbes that has been charted in recent years may not solely be conditioned by triggering molecules or metabolites but also by physical limits to immune system exposure.

Atrial tachyarrhythmia prevention by Shensong Yangxin after catheter ablation for persistent atrial fibrillation: the SS-AFRF trial.

BACKGROUND AND AIMS: Despite advances in technology and techniques, the recurrence rate of persistent atrial fibrillation (AF) following catheter ablation remains high. The Shensong Yangxin (SSYX) capsule, a renowned traditional Chinese medicine formula, is used in the treatment of cardiac arrhythmias. This trial aimed to investigate whether the SSYX can improve clinical outcomes in patients who have undergone catheter ablation for persistent AF. METHODS: A multi-centre, randomized, double-blind, placebo-controlled clinical trial was conducted at 66 centres in China among 920 patients with persistent AF undergoing first ablation. Participants were randomized to oral SSYX, 1.6 g (.4 g/granule) thrice daily (n = 460), or matched placebo (n = 460) for 12 months. The primary endpoint was recurrent atrial tachyarrhythmias lasting for ≥30 s following a blanking period of 3 months. Secondary endpoints included time to first documented atrial tachyarrhythmias, AF burden, cardioversion, stroke/systemic embolism, changes in echocardiographic parameters, and quality-of-life (QoL) score. Analyses were performed according to the intention-to-treat principle. RESULTS: A total of 920 patients underwent randomization (460 assigned to SSYX group and 460 assigned to placebo group). During the follow-up of 12 months, patients assigned to SSYX had a higher event-free rate from recurrent atrial tachyarrhythmias when compared with the placebo group (12-month Kaplan-Meier event-free rate estimates, 85.5% and 77.7%, respectively; hazard ratio, .6; 95% confidence interval .4-.8; P = .001). Patients assigned to receive SSYX had a better QoL score at 12 months compared to those randomized to placebo. There was no significant difference in the incidence of serious adverse events between the two groups. CONCLUSIONS: Treatment with SSYX following radiofrequency catheter ablation for persistent AF reduced the incidence of recurrent atrial tachyarrhythmias and led to clinically significant improvements in QoL during a 12-month follow-up in a Chinese population.

The fibroblast: An emerging key player in thymic T cell selection.

Fibroblasts have recently attracted attention as a key stromal component that controls the immune responses in lymphoid tissues. The thymus has a unique microenvironment comprised of a variety of stromal cells, including fibroblasts and thymic epithelial cells (TECs), the latter of which is known to be important for T cell development because of their ability to express self-antigens. Thymic fibroblasts contribute to thymus organogenesis during embryogenesis and form the capsule and medullary reticular network in the adult thymus. However, the immunological significance of thymic fibroblasts has thus far only been poorly elucidated. In this review, we will summarize the current views on the development and functions of thymic fibroblasts as revealed by new technologies such as multicolor flow cytometry and single cell-based transcriptome profiling. Furthermore, the recently discovered role of medullary fibroblasts in the establishment of T cell tolerance by producing a unique set of self-antigens will be highlighted.

In Vivo Evolution of a Klebsiella pneumoniae Capsule Defect With wcaJ Mutation Promotes Complement-Mediated Opsonophagocytosis During Recurrent Infection.

BACKGROUND: Klebsiella pneumoniae carbapenemase-producing K pneumoniae (KPC-Kp) bloodstream infections are associated with high mortality. We studied clinical bloodstream KPC-Kp isolates to investigate mechanisms of resistance to complement, a key host defense against bloodstream infection. METHODS: We tested growth of KPC-Kp isolates in human serum. In serial isolates from a single patient, we performed whole genome sequencing and tested for complement resistance and binding by mixing study, direct enzyme-linked immunosorbent assay, flow cytometry, and electron microscopy. We utilized an isogenic deletion mutant in phagocytosis assays and an acute lung infection model. RESULTS: We found serum resistance in 16 of 59 (27%) KPC-Kp clinical bloodstream isolates. In 5 genetically related bloodstream isolates from a single patient, we noted a loss-of-function mutation in the capsule biosynthesis gene, wcaJ. Disruption of wcaJ was associated with decreased polysaccharide capsule, resistance to complement-mediated killing, and surprisingly, increased binding of complement proteins. Furthermore, an isogenic wcaJ deletion mutant exhibited increased opsonophagocytosis in vitro and impaired in vivo control in the lung after airspace macrophage depletion in mice. CONCLUSIONS: Loss of function in wcaJ led to increased complement resistance, complement binding, and opsonophagocytosis, which may promote KPC-Kp persistence by enabling coexistence of increased bloodstream fitness and reduced tissue virulence.

The capsular polysaccharide obstructs wall teichoic acid functions in Staphylococcus aureus.

BACKGROUND: The cell envelope of Staphylococcus aureus contains two major secondary cell wall glycopolymers: capsular polysaccharide (CP) and wall teichoic acid (WTA). Both the CP and the WTA are attached to the cell wall and play distinct roles in S. aureus colonization, pathogenesis, and bacterial evasion of host immune defenses. OBJECTIVE: We aimed to investigate whether CP interferes with WTA-mediated properties. METHODS: Strains with natural heterogeneous expression of CP, strains with homogeneous high CP expression and CP-deficient strains were compared to WTA deficient controls regarding WTA dependent phage binding, cell adhesion, IgG deposition, and virulence in vivo. RESULTS: WTA-mediated phage adsorption, specific antibody deposition and cell adhesion were negatively correlated with CP expression. WTA, but not CP, enhanced the bacterial burden in a mouse abscess model, while CP overexpression resulted in intermediate virulence in vivo. CONCLUSIONS: CP protects the bacteria from WTA-dependent opsonization and phage binding. This protection comes at the cost of diminished adhesion to host cells. The highly complex regulation and mostly heterogeneous expression of CP has probably evolved to ensure the survival and optimal physiological adaptation of the bacterial population as a whole.

Clonal Expansion of a Streptococcus pneumoniae Serotype 3 Capsule Variant Sequence Type 700 With Enhanced Vaccine Escape Potential After 13-Valent Pneumococcal Conjugate Vaccine Introduction.

BACKGROUND: Streptococcus pneumoniae serotype 3 remains a problem globally. Malawi introduced 13-valent pneumococcal conjugate vaccine (PCV13) in 2011, but there has been no direct protection against serotype 3 carriage. We explored whether vaccine escape by serotype 3 is due to clonal expansion of a lineage with a competitive advantage. METHODS: The distribution of serotype 3 Global Pneumococcal Sequence Clusters (GPSCs) and sequence types (STs) globally was assessed using sequences from the Global Pneumococcal Sequencing Project. Whole-genome sequences of 135 serotype 3 carriage isolates from Blantyre, Malawi (2015-2019) were analyzed. Comparative analysis of the capsule locus, entire genomes, antimicrobial resistance, and phylogenetic reconstructions were undertaken. Opsonophagocytosis was evaluated using serum samples from vaccinated adults and children. RESULTS: Serotype 3 GPSC10-ST700 isolates were most prominent in Malawi. Compared with the prototypical serotype 3 capsular polysaccharide locus sequence, 6 genes are absent, with retention of capsule polysaccharide biosynthesis. This lineage is characterized by increased antimicrobial resistance and lower susceptibility to opsonophagocytic killing. CONCLUSIONS: A serotype 3 variant in Malawi has genotypic and phenotypic characteristics that could enhance vaccine escape and clonal expansion after post-PCV13 introduction. Genomic surveillance among high-burden populations is essential to improve the effectiveness of next-generation pneumococcal vaccines.

Novel pneumococcal capsule type 33E results from the inactivation of glycosyltransferase WciE in vaccine type 33F.

The polysaccharide (PS) capsule is essential for immune evasion and virulence of Streptococcus pneumoniae. Existing pneumococcal vaccines are designed to elicit anticapsule antibodies; however, the effectiveness of these vaccines is being challenged by the emergence of new capsule types or variants. Herein, we characterize a newly discovered capsule type, 33E, that appears to have repeatedly emerged from vaccine type 33F via an inactivation mutation in the capsule glycosyltransferase gene, wciE. Structural analysis demonstrated that 33E and 33F share an identical repeat unit backbone [→5)-ß-D-Galf2Ac-(1→3)-ß-D-Galp-(1→3)-α-D-Galp-(1→3)-ß-D-Galf-(1→3)-ß-D-Glcp-(1→], except that a galactose (α-D-Galp) branch is present in 33F but not in 33E. Though the two capsule types were indistinguishable using conventional typing methods, the monoclonal antibody Hyp33FM1 selectively bound 33F but not 33E pneumococci. Further, we confirmed that wciE encodes a glycosyltransferase that catalyzes the addition of the branching α-D-Galp and that its inactivation in 33F strains results in the expression of the 33E capsule type. Though 33F and 33E share a structural and antigenic similarity, our pilot study suggested that immunization with a 23-valent pneumococcal PS vaccine containing 33F PS did not significantly elicit cross-opsonic antibodies to 33E. New conjugate vaccines that target capsule type 33F may not necessarily protect against 33E. Therefore, studies of new conjugate vaccines require knowledge of the newly identified capsule type 33E and reliable pneumococcal typing methods capable of distinguishing it from 33F.

Genome-wide association study reveals serovar-associated genetic loci in Riemerella anatipestifer.

BACKGROUND: The disease caused by Riemerella anatipestifer (R. anatipestifer, RA) results in large economic losses to the global duck industry every year. Serovar-related genomic variation, such as the O-antigen and capsular polysaccharide (CPS) gene clusters, has been widely used for serotyping in many gram-negative bacteria. RA has been classified into at least 21 serovars based on slide agglutination, but the molecular basis of serotyping is unknown. In this study, we performed a pan-genome-wide association study (Pan-GWAS) to identify the genetic loci associated with RA serovars. RESULTS: The results revealed a significant association between the putative CPS synthesis gene locus and the serological phenotype. Further characterization of the CPS gene clusters in 11 representative serovar strains indicated that they were highly diverse and serovar-specific. The CPS gene cluster contained the key genes wzx and wzy, which are involved in the Wzx/Wzy-dependent pathway of CPS synthesis. Similar CPS loci have been found in some other species within the family Weeksellaceae. We have also shown that deletion of the wzy gene in RA results in capsular defects and cross-agglutination. CONCLUSIONS: This study indicates that the CPS synthesis gene cluster of R. anatipestifer is a serotype-specific genetic locus. Importantly, our finding provides a new perspective for the systematic analysis of the genetic basis of the R anatipestifer serovars and a potential target for establishing a complete molecular serotyping scheme.

Host immunity involvement in the outcome of phage therapy against hypervirulent Klebsiella pneumoniae infections.

Highly encapsulated hypervirulent Klebsiella pneumoniae (hvKp) causes severe infections. Bacteriophage therapy, an antibiotic alternative, effectively treats bacterial infections. Phage φFK1979 encoding polysaccharide depolymerases can target and disarm the capsule of hvKp FK1979, showing promise against FK1979 infection. Resistant strains induced by φFK1979 are possibly eliminated by host immunity and new phage phiR3 targeting them. We constructed varied immunocompromised FK1979 infection mouse models to assess the therapy efficacy of φFK1979 alone or in combination with phiR3. Survival rates, bacterial loads, histopathology, inflammation, and immune cell distribution of mice were studied. Prompt and adequate administration of φFK1979, rather than phiR3, significantly improved survival rates in mice with different immune statuses. However, immunocompromised mice showed lower efficacy due to reduced tolerance to low-virulence φFK1979-resistant bacteria compared to immunocompetent mice. Adding phiR3 sequentially greatly enhanced therapy efficacy for them, leading to increased survival rates and notable improvements in pathology and inflammation. Immunocompetent mice exhibited the most favorable response to φFK1979 monotherapy, as their immune system cleared φFK1979-resistant bacteria while avoiding a robust response to phiR3 combating φFK1979-resistant bacteria. This study revealed host immunity involvement in the outcome of phage therapy against infections and introduced, for the first time, personalized phage therapy strategies for hvKp-infected mice with varying immune statuses.IMPORTANCEHypervirulent Klebsiella pneumoniae (hvKp), with high capsular polysaccharide production, can cause severe invasive infections. Capsule-targeting phage poses the potential to fight against hvKp. We previously elucidated that the capsule-targeting phage induces resistance in hvKp, while phage-resistant strains exhibit sensitivity to host innate immunity and new phages targeting them. This indicated that phage-resistant strains can be eliminated by the immune system in immunocompetent patients, whereas they may require treatment with phages targeting resistant bacteria in immunocompromised patients. HvKp can infect individuals with varying immune statuses, including both immunocompetent and immunocompromised/deficient patients. This study, for the first time, developed personalized phage therapy strategies for hvKp-infected mice with different immune statuses, optimizing phage therapy against hvKp infections. This research is expected to provide a theoretical foundation and novel insights for clinical phage therapy against hvKp infections, offering significant societal benefits and clinical value.

Randomized Placebo-Controlled Phase 3 Trial of Vibrating Capsule for Chronic Constipation.

BACKGROUND & AIMS: Despite therapeutic advances, effective treatments for chronic constipation remain an unmet need. The vibrating capsule is a nonpharmacologic, orally ingested, programmable capsule that vibrates intraluminally to induce bowel movements. We aimed to determine the efficacy and safety of the vibrating capsule in patients with chronic constipation. METHODS: We conducted a phase 3, double-blind, placebo-controlled trial of patients with chronic constipation, who were randomized to receive either a vibrating or placebo capsule, once daily, 5 days a week for 8 weeks. The primary efficacy end points were an increase of 1 or more complete spontaneous bowel movements per week (CSBM1 responder) or 2 or more CSBMs per week (CSBM2) from baseline during at least 6 of the 8 weeks. Safety analyses were performed. RESULTS: Among 904 patients screened, 312 were enrolled. A greater percentage of patients receiving the vibrating capsule achieved both primary efficacy end points compared with placebo (39.3% vs 22.1%, P = .001 for CSBM1; 22.7% vs 11.4% P = .008 for CSBM2). Significantly greater improvements were seen with the vibrating capsule for the secondary end points of straining, stool consistency, and quality-of-life measures compared with placebo. Adverse events were mild, gastrointestinal in nature, and similar between groups, except that a mild vibrating sensation was reported by 11% of patients in the vibrating capsule group, but none withdrew from the trial. CONCLUSIONS: In patients with chronic constipation, the vibrating capsule was superior to placebo in improving bowel symptoms and quality of life. The vibrating capsule was safe and well tolerated. (Clinical trials.gov, Number: NCT03879239).