Role of ACTG2 Variants in Smooth Muscle Determination and Function in Pediatric Intestinal Pseudo-obstruction. (SMOOTH-PIPO)

The primary objective of this study is to describe the transcriptional impact of R178, R257, R40 or A136 variants of the ACTG2 gene on iPS differentiation mechanisms up to organoids derived from PIPO patient samples versus those derived from control / WT patients (generation of IPS from cultured cell lines), at different stages of their experimental ex vivo development.

Study Overview

• Status: Recruiting
• Conditions: PIPO
• Intervention / Treatment: Procedure: Biopsy

Detailed Description

Recruited patients will be sampled during a consultation: a blood sample and a biopsy will be taken directly from the patient. Once these samples have been taken, they will be cultured to be reprogrammed into iPS cells, then grown and differentiated into intestinal organoids.

Various experiments will be carried out (as described in the outcomes) to identify at molecular, cellular and tissue level the mechanisms altered in patients with an R178, R257, R40 or A136 variant, assessing their consequence(s) on the development and functionality of the digestive mesenchyme.

• Study Type: Interventional
• Enrollment (Estimated): 4
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: John Rendu, Dr; Phone Number: +33 0476765573; Email: jrendu@chu-grenoble.fr
• Study Contact Backup: Name: Mandy Leger; Phone Number: +33 0476768410; Email: mleger@chu-grenoble.fr

Study Locations

• France
  • Montpellier, France, 34295
    • Recruiting
    • Phymedexp Inserm U1046 - Cnrs Umr 9214
    • Contact: Pascal de Santa Barbara, Dr; Phone Number: +33 0467515234; Email: Pascal.de-Santa-Barbara@inserm.fr
  • Nantes, France, 44035
    • Recruiting
    • Tens - Inserm Un Umr 1235
    • Contact: Maxime Mahé, Dr; Phone Number: +33 0240412885; Email: maxime.mahe@inserm.fr
  • Paris, France, 75019
    • Recruiting
    • AP-HP Hôpital Robert Debré
    • Contact: Emmanuelle DUGELAY, Dr; Phone Number: +33 0140032020; Email: emmanuelle.dugelay@aphp.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

PIPO Population:

1. Minor or adult patient ≥ 4 years of age
2. Patient with PIPO before age 18
3. Male or female
4. Patient with PIPO meeting at least 2 of the ESPGHAN criteria (Thapar et al 2018) and carrying the R178, R257, R40 or A136 mutation of the ACTG2 gene.
5. Patient whose assent has been obtained and whose legal guardians have given their written informed consent
6. Patient affiliated to the French Social Security system or benefiting from an equivalent plan

WT population:

- iPS cell lines MS573 or WT8288 or 202CT or SD378M, from the Nantes University Hospital biological collection and generated from samples from control patients without POIC who have consented to donate their samples.

Exclusion Criteria:

PIPO population :

1. Patients with a history of radiotherapy treatment
2. Patient with lymphocyte lineage damage

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Factorial Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PIPO patients; PIPO patients with variants of interest	Procedure: Biopsy; A skin biopsy and a blood sample will be taken to culture the iPS cells and intestinal organoids.; Other Names: Blood sample
Other: WT; Control arm, same experiments as for patients. Samples from specific cell lines	Procedure: Biopsy; A skin biopsy and a blood sample will be taken to culture the iPS cells and intestinal organoids.; Other Names: Blood sample

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Description of the transcriptional impact of R178, R257, R40 or A136 variants of the ACTG2 gene	Difference in transcript expression (%) in RNASeq transcriptomic analysis between samples carrying the R178, R257, R40 or A136 variants of the ACTG2 gene on the differentiation mechanisms of iPS up to organoids derived from PIPO patient samples versus those derived from control patients	At different stages of their experimental ex vivo development (mesenchymal progenitors, determined smooth muscle cells, differentiated smooth muscle cells and 3D organization of smooth muscle) through study completion, an average of 5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluate the impact of R178, R257, R40 or A136 variants of the ACTG2 gene on gastrointestinal contractile function between mutant versus WT organoids.	Difference (%) in isometric contraction force between mutant versus WT organoids by electrical stimulation and specific agonist.	At different stages of their experimental ex vivo development (mesenchymal progenitors, determined smooth muscle cells, differentiated smooth muscle cells and 3D organization of smooth muscle) an average of 5 years
Evaluate the immunofluorescence labeling differential between mutant and WT cells from IPS and organoids	Difference in fluorescence (%) between mutant and WT cells as cell stages from iPS to organoids	At different stages of their experimental ex vivo development (mesenchymal progenitors, determined smooth muscle cells, differentiated smooth muscle cells and 3D organization of smooth muscle) an average of 5 years
Evaluate the impact of R178, R257, R40 or A136 mutations of the ACTG2 gene on the actin network of fibroblasts derived from skin samples of diseased patients versus those of WTpatients.	Difference in actin network labeling by immunofluorescence (%) between skin fibroblasts from PIPO and WT patients.	At different stages of their experimental ex vivo development (mesenchymal progenitors, determined smooth muscle cells, differentiated smooth muscle cells and 3D organization of smooth muscle) an average of 5 years
Evaluate the effect of reversion of the R178, R257, R40 or A136 mutation versus WT on functionality and contractility during differentiation of cells into organoids.	Difference in isometric contraction strength (%) between mutant versus WT versus revertant organoids via specific agonist and electrical stimulation.	At different stages of their experimental ex vivo development (mesenchymal progenitors, determined smooth muscle cells, differentiated smooth muscle cells and 3D organization of smooth muscle) an average of 5 years
Assessing the potential of a chemical library to correct the phenotype	Identification of molecules inducing a significant difference in isometric contraction force (%) between treated mutant organoids, untreated mutant organoids and treated and untreated WT	At different stages of their experimental ex vivo development (mesenchymal progenitors, determined smooth muscle cells, differentiated smooth muscle cells and 3D organization of smooth muscle) an average of 5 years

Collaborators and Investigators

• Sponsor: University Hospital, Grenoble

Publications and helpful links

General Publications

• Zenzeri L, Tambucci R, Quitadamo P, Giorgio V, De Giorgio R, Di Nardo G. Update on chronic intestinal pseudo-obstruction. Curr Opin Gastroenterol. 2020 May;36(3):230-237. doi: 10.1097/MOG.0000000000000630.
• Fournier N, Fabre A. Smooth muscle motility disorder phenotypes: A systematic review of cases associated with seven pathogenic genes (ACTG2, MYH11, FLNA, MYLK, RAD21, MYL9 and LMOD1). Intractable Rare Dis Res. 2022 Aug;11(3):113-119. doi: 10.5582/irdr.2022.01060.
• Assia Batzir N, Kishor Bhagwat P, Larson A, Coban Akdemir Z, Baglaj M, Bofferding L, Bosanko KB, Bouassida S, Callewaert B, Cannon A, Enchautegui Colon Y, Garnica AD, Harr MH, Heck S, Hurst ACE, Jhangiani SN, Isidor B, Littlejohn RO, Liu P, Magoulas P, Mar Fan H, Marom R, McLean S, Nezarati MM, Nugent KM, Petersen MB, Rocha ML, Roeder E, Smigiel R, Tully I, Weisfeld-Adams J, Wells KO; Baylor-Hopkins Center for Mendelian Genomics; Posey JE, Lupski JR, Beaudet AL, Wangler MF. Recurrent arginine substitutions in the ACTG2 gene are the primary driver of disease burden and severity in visceral myopathy. Hum Mutat. 2020 Mar;41(3):641-654. doi: 10.1002/humu.23960. Epub 2019 Dec 19.
• de Santa Barbara P, van den Brink GR, Roberts DJ. Development and differentiation of the intestinal epithelium. Cell Mol Life Sci. 2003 Jul;60(7):1322-32. doi: 10.1007/s00018-003-2289-3.
• Mahe MM, Brown NE, Poling HM, Helmrath MA. In Vivo Model of Small Intestine. Methods Mol Biol. 2017;1597:229-245. doi: 10.1007/978-1-4939-6949-4_17.

Study record dates

Study Major Dates

• Study Start (Actual): February 4, 2026
• Primary Completion (Estimated): February 3, 2032
• Study Completion (Estimated): February 3, 2032

Study Registration Dates

• First Submitted: October 11, 2024
• First Submitted That Met QC Criteria: November 12, 2024
• First Posted (Actual): November 13, 2024

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 22, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: CIPO; organoid; iPS; PIPO; ACTG2; pseudo-obstruction; Pediatric Intestinal Pseudo-Obstruction; Chronic Intestinal Pseudo-obstruction
• Additional Relevant MeSH Terms: Intestinal Diseases; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Obstruction; Ileus; Intestinal Pseudo-Obstruction; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Cytological Techniques; Cytodiagnosis; Diagnostic Techniques, Surgical; Biopsy; Blood Specimen Collection
• Other Study ID Numbers: 38RC23.0368; 2024-A01516-41 (Other Identifier: ID RCB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No