Genetic Mapping and Biochemical Basis of Yellow Feather Pigmentation in Budgerigars.

Parrot feathers contain red, orange, and yellow polyene pigments called psittacofulvins. Budgerigars are parrots that have been extensively bred for plumage traits during the last century, but the underlying genes are unknown. Here we use genome-wide association mapping and gene-expression analysis to map the Mendelian blue locus, which abolishes yellow pigmentation in the budgerigar. We find that the blue trait maps to a single amino acid substitution (R644W) in an uncharacterized polyketide synthase (MuPKS). When we expressed MuPKS heterologously in yeast, yellow pigments accumulated. Mass spectrometry confirmed that these yellow pigments match those found in feathers. The R644W substitution abolished MuPKS activity. Furthermore, gene-expression data from feathers of different bird species suggest that parrots acquired their colors through regulatory changes that drive high expression of MuPKS in feather epithelia. Our data also help formulate biochemical models that may explain natural color variation in parrots. VIDEO ABSTRACT.

Beyond the Four Bases: A Home Run for Synthetic Epigenetic Control?

Park et al. (2019) create a synthetic self-propagating adenine methylation system for epigenetic control in human cells. Targeting adenine allows their modular system to act orthogonally to most epigenetic processes, thereby opening the door for novel methods of controlling gene expression.

The clinical KRAS(G12C) inhibitor AMG 510 drives anti-tumour immunity.

KRAS is the most frequently mutated oncogene in cancer and encodes a key signalling protein in tumours1,2. The KRAS(G12C) mutant has a cysteine residue that has been exploited to design covalent inhibitors that have promising preclinical activity3-5. Here we optimized a series of inhibitors, using novel binding interactions to markedly enhance their potency and selectivity. Our efforts have led to the discovery of AMG 510, which is, to our knowledge, the first KRAS(G12C) inhibitor in clinical development. In preclinical analyses, treatment with AMG 510 led to the regression of KRASG12C tumours and improved the anti-tumour efficacy of chemotherapy and targeted agents. In immune-competent mice, treatment with AMG 510 resulted in a pro-inflammatory tumour microenvironment and produced durable cures alone as well as in combination with immune-checkpoint inhibitors. Cured mice rejected the growth of isogenic KRASG12D tumours, which suggests adaptive immunity against shared antigens. Furthermore, in clinical trials, AMG 510 demonstrated anti-tumour activity in the first dosing cohorts and represents a potentially transformative therapy for patients for whom effective treatments are lacking.

A first-in-human phase 1 study of nofazinlimab, an anti-PD-1 antibody, in advanced solid tumors and in combination with regorafenib in metastatic colorectal cancer.

BACKGROUND: We assessed nofazinlimab, an anti-PD-1 antibody, in solid tumors and combined with regorafenib in metastatic colorectal cancer (mCRC). METHODS: This phase 1 study comprised nofazinlimab dose escalation (phase 1a) and expansion (phase 1b), and regorafenib dose escalation (80 or 120 mg QD, days 1-21 of 28-day cycles) combined with 300-mg nofazinlimab Q4W (part 2a) to determine safety, efficacy, and RP2D. RESULTS: In phase 1a (N = 21), no dose-limiting toxicity occurred from 1 to 10 mg/kg Q3W, with 200 mg Q3W determined as the monotherapy RP2D. In phase 1b (N = 87), 400-mg Q6W and 200-mg Q3W regimens were found comparable. In part 2a (N = 14), both regimens were deemed plausible RP2Ds. Fatigue was the most frequent treatment-emergent adverse event (AE) in this study. Any-grade and grade 3/4 nofazinlimab-related AEs were 71.4% and 14.3%, 56.3% and 5.7%, and 57.1% and 21.4% in phases 1a, 1b, and part 2a, respectively. ORRs were 14.3% and 25.3% in phases 1a and 1b, respectively. In part 2a, no patients had radiological responses. CONCLUSIONS: Nofazinlimab monotherapy was well tolerated and demonstrated preliminary anti-tumor activity in multiple tumor types. Regorafenib plus nofazinlimab had a manageable safety profile but was not associated with any response in mCRC. CLINICAL TRIAL REGISTR ATION: Clinicaltrials.gov (NCT03475251).

KRASG12C Inhibition with Sotorasib in Advanced Solid Tumors.

BACKGROUND: No therapies for targeting KRAS mutations in cancer have been approved. The KRAS p.G12C mutation occurs in 13% of non-small-cell lung cancers (NSCLCs) and in 1 to 3% of colorectal cancers and other cancers. Sotorasib is a small molecule that selectively and irreversibly targets KRASG12C. METHODS: We conducted a phase 1 trial of sotorasib in patients with advanced solid tumors harboring the KRAS p.G12C mutation. Patients received sotorasib orally once daily. The primary end point was safety. Key secondary end points were pharmacokinetics and objective response, as assessed according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1. RESULTS: A total of 129 patients (59 with NSCLC, 42 with colorectal cancer, and 28 with other tumors) were included in dose escalation and expansion cohorts. Patients had received a median of 3 (range, 0 to 11) previous lines of anticancer therapies for metastatic disease. No dose-limiting toxic effects or treatment-related deaths were observed. A total of 73 patients (56.6%) had treatment-related adverse events; 15 patients (11.6%) had grade 3 or 4 events. In the subgroup with NSCLC, 32.2% (19 patients) had a confirmed objective response (complete or partial response) and 88.1% (52 patients) had disease control (objective response or stable disease); the median progression-free survival was 6.3 months (range, 0.0+ to 14.9 [with + indicating that the value includes patient data that were censored at data cutoff]). In the subgroup with colorectal cancer, 7.1% (3 patients) had a confirmed response, and 73.8% (31 patients) had disease control; the median progression-free survival was 4.0 months (range, 0.0+ to 11.1+). Responses were also observed in patients with pancreatic, endometrial, and appendiceal cancers and melanoma. CONCLUSIONS: Sotorasib showed encouraging anticancer activity in patients with heavily pretreated advanced solid tumors harboring the KRAS p.G12C mutation. Grade 3 or 4 treatment-related toxic effects occurred in 11.6% of the patients. (Funded by Amgen and others; CodeBreaK100 ClinicalTrials.gov number, NCT03600883.).

Toward a translationally independent RNA-based synthetic oscillator using deactivated CRISPR-Cas.

In synthetic circuits, CRISPR-Cas systems have been used effectively for endpoint changes from an initial state to a final state, such as in logic gates. Here, we use deactivated Cas9 (dCas9) and deactivated Cas12a (dCas12a) to construct dynamic RNA ring oscillators that cycle continuously between states over time in bacterial cells. While our dCas9 circuits using 103-nt guide RNAs showed irregular fluctuations with a wide distribution of peak-to-peak period lengths averaging approximately nine generations, a dCas12a oscillator design with 40-nt CRISPR RNAs performed much better, having a strongly repressed off-state, distinct autocorrelation function peaks, and an average peak-to-peak period length of ∼7.5 generations. Along with free-running oscillator circuits, we measure repression response times in open-loop systems with inducible RNA steps to compare with oscillator period times. We track thousands of cells for 24+ h at the single-cell level using a microfluidic device. In creating a circuit with nearly translationally independent behavior, as the RNAs control each others' transcription, we present the possibility for a synthetic oscillator generalizable across many organisms and readily linkable for transcriptional control.

CRISPR/Cas9 cleavages in budding yeast reveal templated insertions and strand-specific insertion/deletion profiles.

Harnessing CRISPR-Cas9 technology provides an unprecedented ability to modify genomic loci via DNA double-strand break (DSB) induction and repair. We analyzed nonhomologous end-joining (NHEJ) repair induced by Cas9 in budding yeast and found that the orientation of binding of Cas9 and its guide RNA (gRNA) profoundly influences the pattern of insertion/deletions (indels) at the site of cleavage. A common indel created by Cas9 is a 1-bp (+1) insertion that appears to result from Cas9 creating a 1-nt 5' overhang that is filled in by a DNA polymerase and ligated. The origin of +1 insertions was investigated by using two gRNAs with PAM sequences located on opposite DNA strands but designed to cleave the same sequence. These templated +1 insertions are dependent on the X-family DNA polymerase, Pol4. Deleting Pol4 also eliminated +2 and +3 insertions, which are biased toward homonucleotide insertions. Using inverted PAM sequences, we also found significant differences in overall NHEJ efficiency and repair profiles, suggesting that the binding of the Cas9:gRNA complex influences subsequent NHEJ processing. As with events induced by the site-specific HO endonuclease, CRISPR-Cas9-mediated NHEJ repair depends on the Ku heterodimer and DNA ligase 4. Cas9 events are highly dependent on the Mre11-Rad50-Xrs2 complex, independent of Mre11's nuclease activity. Inspection of the outcomes of a large number of Cas9 cleavage events in mammalian cells reveals a similar templated origin of +1 insertions in human cells, but also a significant frequency of similarly templated +2 insertions.

Aortic Root Distortion During Balloon Angioplasty of Right Ventricular Outflow Tract Prior to Transcatheter Pulmonary Valve Implantation.

We describe our experience with aortic root distortion in transcatheter pulmonary valve implantation (TPVI). Aortic root distortion (AD) can be observed with balloon angioplasty of the right ventricular outflow tract (RVOT), but its long-term significance is unknown. This has been a common finding in our institution, though not fully appreciated in our early experience. Retrospective review of procedural angiograms prior to TPVI and follow up imaging was performed. Between June 2012 and October 2017, 47 patients underwent catheterization to attempt TPVI. Five patients had coronary compression which precluded TPVI (one with significant AD as well). Four patients had significant AD and did not receive TPVI. Of the remaining 38 successful TPVI, 20 had adequate imaging to assess the aortic root. Four patients had severe AD, 7 had mild AD, and 9 with no AD. Severity of AI did not correlate with degree of AD. Median follow up after TPVI was 46 months (IQR 21-67). Of the 4 patients with severe AD who received TPVI, 1 has new mild AI with 78 months follow up. Of the 18 patients who received TPVI without adequate arch imaging, 2 patients have new mild AI with 86 and 75 months follow up. AD during RVOT angioplasty is a relatively common finding. In our early experience, some patients who were retrospectively identified to have severe AD received TPVI. These patients have done well, though further data is needed before considering severe AD a benign finding.

Complete Reconstitution and Deorphanization of the 3 MDa Nocardiosis-Associated Polyketide Synthase.

Several Nocardia strains associated with nocardiosis, a potentially life-threatening disease, house a nonamodular assembly line polyketide synthase (PKS) that presumably synthesizes an unknown polyketide. Here, we report the discovery and structure elucidation of the NOCAP (nocardiosis-associated polyketide) aglycone by first fully reconstituting the NOCAP synthase in vitro from purified protein components followed by heterologous expression in E. coli and spectroscopic analysis of the purified products. The NOCAP aglycone has an unprecedented structure comprised of a substituted resorcylaldehyde headgroup linked to a 15-carbon tail that harbors two conjugated all-trans trienes separated by a stereogenic hydroxyl group. This report is the first example of reconstituting a trans-acyltransferase assembly line PKS in vitro and of using these approaches to "deorphanize" a complete assembly line PKS identified via genomic sequencing. With the NOCAP aglycone in hand, the stage is set for understanding how this PKS and associated tailoring enzymes confer an advantage to their native hosts during human Nocardia infections.

Large-scale recoding of a bacterial genome by iterative recombineering of synthetic DNA.

The ability to rewrite large stretches of genomic DNA enables the creation of new organisms with customized functions. However, few methods currently exist for accumulating such widespread genomic changes in a single organism. In this study, we demonstrate a rapid approach for rewriting bacterial genomes with modified synthetic DNA. We recode 200 kb of the Salmonella typhimurium LT2 genome through a process we term SIRCAS (stepwise integration of rolling circle amplified segments), towards constructing an attenuated and genetically isolated bacterial chassis. The SIRCAS process involves direct iterative recombineering of 10-25 kb synthetic DNA constructs which are assembled in yeast and amplified by rolling circle amplification. Using SIRCAS, we create a Salmonella with 1557 synonymous leucine codon replacements across 176 genes, the largest number of cumulative recoding changes in a single bacterial strain to date. We demonstrate reproducibility over sixteen two-day cycles of integration and parallelization for hierarchical construction of a synthetic genome by conjugation. The resulting recoded strain grows at a similar rate to the wild-type strain and does not exhibit any major growth defects. This work is the first instance of synthetic bacterial recoding beyond the Escherichia coli genome, and reveals that Salmonella is remarkably amenable to genome-scale modification.

Synthetic genome recoding: new genetic codes for new features.

Full genome recoding, or rewriting codon meaning, through chemical synthesis of entire bacterial chromosomes has become feasible in the past several years. Recoding an organism can impart new properties including non-natural amino acid incorporation, virus resistance, and biocontainment. The estimated cost of construction that includes DNA synthesis, assembly by recombination, and troubleshooting, is now comparable to costs of early stage development of drugs or other high-tech products. Here, we discuss several recently published assembly methods and provide some thoughts on the future, including how synthetic efforts might benefit from the analysis of natural recoding processes and organisms that use alternative genetic codes.

Pudendal nerve terminal motor latency testing does not provide useful information in guiding therapy for fecal incontinence.

PURPOSE: Pudendal nerve terminal motor latency (PNTML) testing is a standard recommendation for the evaluation of fecal incontinence. Its role in guiding therapy for fecal incontinence has been previously questioned. The aim of this study was to evaluate the relationship between PNTML testing and anorectal dysfunction. METHODS: This was a retrospective analysis of data collected prospectively from patients who presented to a pelvic floor disorder center from 2007 to 2015. The relationship between PNTML (normal versus delayed) and anorectal manometry, fecal incontinence severity, and fecal incontinence-related quality of life scores was assessed using the Wilcoxon-Mann-Whitney test. RESULTS: Two hundred sixty-nine patients underwent PNTML testing, and 91.1% were female (N = 245) (median age 62.2 years). Normal PNTML was seen in 234 (87.0%) patients. Among 268 patients who underwent anorectal manometry, delayed PNTML was only significantly associated with median maximum anal squeeze pressure (P = 0.04). Delayed PNTML was not associated with a decrease in median fecal incontinence severity or fecal incontinence-related quality of life scores (N = 99). CONCLUSIONS: PNTML was only associated with median maximum anal squeeze pressure, and it was not associated with patient-reported severity of symptoms of fecal incontinence, changes in quality of life attributable to fecal incontinence, median mean resting anal pressure, or median maximum resting anal pressure. PNTML testing may not be relevant to current therapeutic algorithms for fecal incontinence and its routine use should be questioned.

Melody valve implantation within freestyle stentless porcine aortic heterograft.

BACKGROUND: The Melody transcatheter pulmonary valve has been implanted successfully worldwide since its first implant in 2000. The vast majority of these valves have been implanted in pulmonary homografts. In our institution, the most common valve used for pulmonary valve replacement is the Medtronic Freestyle stentless porcine aortic heterograft. OBJECTIVE: We describe our experience implanting the Melody valve within the Freestyle heterograft. METHODS: Retrospective chart review was performed. RESULTS: Between June 2012 and June 2015, 19 Melody valves were placed within Freestyle heterografts. The most common indication for intervention was pulmonary stenosis. Following pre-stent and Melody valve implantation, right ventricle-to-pulmonary artery gradient decreased from 38.1 ± 12.1 to 10 ± 4.7 mm Hg (P < 0.001), and right ventricular pressure decreased from 61.7 ± 17.8 to 35.6 ± 10.2 mm Hg (P < 0.001). Two procedural adverse events occurred. At median follow-up of 24 months (range 2-48 months), no patients had mean right ventricular outflow tract gradients >30 mm Hg or worse than mild insufficiency. No valve reinterventions have been necessary and no episodes of endocarditis have been observed. CONCLUSIONS: The Melody valve can be implanted successfully within a stentless aortic bioprosthesis with good short- and intermediate-term longevity. © 2016 Wiley Periodicals, Inc.

Percutaneous device occlusion of hepatocardiac venous collateral via left transhepatic access in a patient with heterotaxy syndrome following Fontan procedure.

Venovenous collateral vessels are a common cause for desaturation in patients who have undergone a Fontan procedure. We describe a patient with heterotaxy syndrome (leftward pointing apex) and complex single ventricle with Fontan physiology that was desaturated due to a hepatocardiac vein. The vessel was entered via a left transhepatic access and was successfully occluded using an Amplatzer Vascular Plug.

Administration of chemotherapy in patients on dialysis.

The prevalence of patients on dialysis has increased and these patients present a challenge for chemotherapy administration when diagnosed with cancer. A consensus on the dosage and timing of different chemotherapeutic agents in relation to dialysis has not been established. We describe the pattern of care and treatment outcome for cancer patients on dialysis in our institution. The dataset from the Australia and New Zealand Dialysis and Transplant Registry of patients on dialysis who had a diagnosis of cancer was obtained and matched to the pharmacy records in our institution to identify patients who had received chemotherapy while on dialysis. Relevant clinical information including details of the dialysis regimen, chemotherapy administration and adverse events was extracted for analysis. Between July 1999 and July 2014, 21 patients on dialysis were included for analysis. Five (23.8%) received chemotherapy, most of which was administered before dialysis sessions. As a result of adverse events, one patient discontinued treatment; two other patients required dose reduction or treatment delay. Chemotherapy administration was feasible in cancer patients on dialysis, but chemotherapy usage was low. Better understanding of the altered pharmacokinetics in patients on dialysis may improve chemotherapy access and practice.

Effect of Coexisting Pelvic Floor Disorders on Fecal Incontinence Quality of Life Scores: A Prospective, Survey-Based Study.

BACKGROUND: The association between an objective measure of fecal incontinence severity and patient-reported quality of life is poorly understood. OBJECTIVE: The purpose of this study was to evaluate patients with various degrees of fecal incontinence to determine whether their quality of life as measured by the Fecal Incontinence Quality of Life Scale is affected by coexisting pelvic floor disorders. DESIGN: This was a prospective, survey-based study. SETTINGS: The study was conducted at a tertiary pelvic floor disorders center. PATIENTS: Included patients were all of those presenting between January 2007 and March 2014. MAIN OUTCOME MEASURES: Survey data were analyzed to determine the association between Fecal Incontinence Severity Index and Fecal Incontinence Quality of Life Scale, as well as scores from the Constipation Severity Instrument, Pelvic Floor Impact Questionnaire, Pelvic Organ Distress Inventory, and Urinary Distress Inventory. RESULTS: A total of 585 patients reported fecal incontinence ranging from none (n = 191) to mild/moderate (n = 159) to severe (n = 235). As expected, patients with severe fecal incontinence have worse scores on all fecal incontinence quality-of-life subscales (lifestyle, coping/behavior, depression/self-perception, and embarrassment) and worse colorectal/anal symptoms than those with mild/moderate or no fecal incontinence (p < 0.0001). Patients with severe fecal incontinence also have worse bladder/urinary symptoms (p ≤ 0.0001). Pelvic organ prolapse and constipation symptoms were similar between groups (p ≥ 0.61). After correcting for baseline differences in patient comorbidities and bladder/urinary symptoms, a significant association persisted between Fecal Incontinence Severity Index and all of the subscales of the fecal incontinence quality-of-life instrument (p < 0.0001). However, urinary distress scores also remained significantly associated with all of the fecal incontinence quality-of-life subscales except for embarrassment after risk adjustment (p < 0.01). LIMITATIONS: Nongeneral population and a lack of patient data on previous medical management of fecal incontinence were limitations of this study. CONCLUSIONS: The Fecal Incontinence Quality of Life Scale correlates strongly with instruments measuring both fecal and urinary incontinence. This underscores the importance of quantifying the presence or absence of coexistent urinary leakage in studies where a drop in fecal incontinence quality of life is considered a primary end point.

The initiation ketosynthase (FabH) is the sole rate-limiting enzyme of the fatty acid synthase of Synechococcus sp. PCC 7002.

Cyanobacteria are Gram-negative bacteria that are desirable hosts for biodiesel production, because they are photosynthetic, relatively fast growing, and can secrete products. We have reconstituted the fatty acid synthase (FAS) of the cyanobacterium Synechococcus sp. PCC 7002 and subjected it to in vitro kinetic analysis. Our data revealed that the overall rate of this metabolic pathway is exclusively limited by the FabH ketosynthase, which initiates product synthesis by condensing malonyl-ACP with acetyl-CoA to form acetoacetyl-ACP. This finding sharply contrasts with our previous findings that the Escherichia coli FAS is predominantly limited by its dehydratase (FabZ) and enoyl reductase (FabI) activities and that FabH activity is not limiting. We therefore reconstituted and analyzed a set of "hybrid" FASs. When the Synechococcus FabH was used to replace its counterpart in the reconstituted E. coli FAS, the resulting synthase was strongly limited by FabH activity. Conversely, replacement of the E. coli FabZ with its Synechococcus homolog dramatically alleviated the dependence of E. coli FAS activity on FabZ. In agreement with this finding, introduction of the E. coli FabH in the Synechococcus FAS virtually eliminated its dependence on this subunit, whereas substitution of the Synechococcus FabZ with its E. coli homolog shifted a substantial fraction of the overall flux control in the Synechococcus FAS to FabZ. Our findings demonstrate that the rate-limiting steps can differ dramatically between closely related bacterial fatty acid synthases, and that such regulatory behavior is fundamentally the property of the controlling enzyme(s).

How well informed is the informed consent for cancer clinical trials?

AIMS: The purpose of this study was to analyze the content of informed consent forms for clinical trials in medical oncology to assess readability, determine their completeness, and identify any shortcomings. METHODS: Informed consent forms for Phase I-III studies that were conducted at two tertiary care cancer centers over a 3-year period were reviewed. Information pertaining to length of the informed consent form, research regimen/methods, treatment agent, potential risks, and benefits was extracted. The reading level was assessed by Flesch-Kincaid and Gunning-Fog index readability tests. RESULTS: All of the 112 informed consent forms clearly stated the voluntary nature of participation. Nearly one half of the forms (51.8%) were of Phase I studies. The median length of informed consent form was 20 pages (range: 8-28). A detailed estimation of the frequency or intensity of risks (range: 3-8 pages) was provided. The average reading level of the informed consent forms was high (Flesch-Kincaid Grade Level of 9.8), which corresponds roughly to 10th-grade reading level. Less than 15% of all consent forms were written at the recommended eighth-grade reading level. A substantial number of forms did not report a potential risk to pregnant/lactating women (16.9%), mechanism of action of the investigational agent (34.8%), study schema (77.6%), a possibility of receiving sub-therapeutic dose (37%), or death (12.5%). Nearly one half of the forms (49.1%) stated clearly that individual participants may not benefit. CONCLUSION: Overall, these informed consent forms provided a detailed description of the trials in accordance to international guidelines. However, there remains room for improvement, particularly in areas of readability and document length.

A challenging case of emergency redo surgery for acute type A aortic dissecting aneurysm of ascending and aortic arch with frozen elephant trunk following aortic root replacement.

Redo ascending and aortic arch surgeries following previous cardiac or aortic surgery are associated with high risk of morbidity and mortality due to multiple factors included sternal re-entry injury, extensive aortic arch surgery, emergency aortic surgery, prolonged cardiopulmonary bypass duration, poor heart function, and patients with older age. Therefore, appropriate surgical strategies are important. We report a case of a 72-year-old gentleman with previous surgery of aortic root replacement who presented with acute Type A aortic dissecting aneurysm of ascending and aortic arch complicated with left hemothorax, which was successfully treated by emergency redo aortic surgery with frozen elephant trunk (FET) technique.

Toxigenic Clostridium perfringens isolated from at-risk pediatric inflammatory bowel disease patients.

BACKGROUND AND AIMS: The goal was to identify microbial drivers of IBD, by investigating mucosal-associated bacteria and their detrimental products in IBD patients. METHODS: We directly cultured bacterial communities from mucosal biopsies from pediatric gastrointestinal patients and examined for pathogenicity-associated traits. Upon identifying C. perfringens as toxigenic bacteria present in mucosal biopsies, we isolated strains and further characterized toxicity and prevalence. RESULTS: Mucosal biopsy microbial composition differed from corresponding stool samples. C. perfringens was present in 8 of 9 patients' mucosal biopsies, correlating with hemolytic activity, while not in all corresponding stool samples. Large IBD datasets showed higher C. perfringens prevalence in stool samples of IBD adults (18.7-27.1%) versus healthy (5.1%). In vitro, C. perfringens supernatants were toxic to cell types beneath the intestinal epithelial barrier, including endothelial, neuroblasts, and neutrophils, while impact on epithelial cells was less pronounced, suggesting C. perfringens may be damaging particularly when barrier integrity is compromised. Further characterization using purified toxins and genetic insertion mutants confirmed PFO toxin was sufficient for toxicity. Toxin RNA signatures were found in the original patient biopsies by PCR, suggesting intestinal production. C. perfringens supernatants also induced activation of neuroblast and dorsal root ganglion neurons in vitro, suggesting C. perfringens in inflamed mucosal tissue may directly contribute to abdominal pain, a frequent IBD symptom. CONCLUSIONS: Gastrointestinal carriage of certain toxigenic C. perfringens may have an important pathogenic impact on IBD patients. These findings support routine monitoring of C. perfringens and PFO toxins and potential treatment in patients.