Senescent Stem and Transient Amplifying Cells in Crohn’s Disease Intestine

[문형철]

Inflamm Bowel Dis. 2020 Feb; 26(2): e8–e9.

Published online 2019 Nov 26. doi: 10.1093/ibd/izz295

PMCID: PMC6943680

PMID: 31769481

Senescent Stem and Transient Amplifying Cells in Crohn’s Disease Intestine

Xiaoyan Wang, MSc,1 Hendrika Bootsma, MD, PhD,1 Frans Kroese, PhD,1 Gerard Dijkstra, MD, PhD,2 and Sarah Pringle, PhD1

Author information Copyright and License information PMC Disclaimer

We demonstrate presence of senescent (p16+, p21+) epithelial cells in the stem and transient amplifying cell niches of the intestine in Crohn’s disease. This may explain why Crohn’s lesions recur in the same places.

To the Editors,

The inflammatory lesions of Crohn’s disease occur most preval‎ently in the terminal ileum and colon. Recurrent lesions in these areas suggest a defect in the ability of the local intestinal stem cell population to maintain homeostasis of the gut. We have previously demonstrated a reduction in functionality of salivary gland (SG) progenitor cells (SGPCs) isolated from patients with the autoimmune disease primary Sjögren syndrome.1, 2 When we examined tissue from patients with early Crohn’s disease, we observed p16+ cells resident in the stem cell niches of the intestine (Figs. 1A–C). Expression‎ of a second senescence marker, p21, was observed in the transient amplifying (TA) cell niches and the columnar cells of the intestine; Fig. 1E, ​,F).F). These observations suggest that persistence of lesions in the same intestinal area may be attributable to senescent stem cells, which are no longer capable of proliferating to generate new enterocytes. The reason for the predilection of Crohn’s lesions for the terminal ileum and colon areas remains unknown. Studies have suggested that infection with Mycobacterium avium paratuberculosis (MAP) may be a causal factor in Crohn’s disease.3Mycobacterium avium paratuberculosis is capable of initiating and maintaining chronic inflammation of the intestine. Mycobacterium avium paratuberculosis congregation in potential low traffic areas of the intestine, perhaps where Crohn’s lesions are most often found, may provide an explanation for this. Once inflammation is initiated, pro-inflammatory cytokines such as INF-α, TNF-α, and interleukin (IL)-6 are likely to induce local epithelial cell death and/or stem cell over proliferation.4 Both facets increase pressure on resident stem cells to generate replacement cells and may promote senescence of the stem cell pool. In addition to reduced functionality, senescent cells also express the senescence-associated secretory proteome (SASP) composed of pro-inflammatory cytokines (IL-6, IL-1, CXCL5, CXCL10, CCL1, CCL2, and TNF-α).5 Senescence-associated secretory proteome expression‎ promotes senescence in neighboring cells and therefore represents a potentially pathological phenotype.5 When pro-inflammatory cytokines were applied to healthy SG progenitor cell cultures, proliferation was induced. Presuming the same effect takes place in the intestine, p16+ and p21+ cells in Crohn’s disease may also promote development of replicative senescence in neighboring progenitor cells. Appreciation of the effects of an inflamed environment on epithelial stem cells—and particularly epithelial progenitor cells—is growing and will be crucial to molding our therapeutic options toward not only resolution of inflammation but also recovery of epithelial integrity.

크론병의 염증성 병변은 말기 회장과 결장에서 가장 흔하게 발생합니다. 이러한 부위의 재발성 병변은 국소 장 줄기세포 집단이 장의 항상성을 유지하는 능력에 결함이 있음을 시사합니다. 우리는 이전에 자가면역질환인 원발성 쇼그렌 증후군 환자에서 분리한 침샘(SG) 전구세포(SGPC)의 기능 감소를 입증한 바 있습니다.1, 2 초기 크론병 환자의 조직을 검사한 결과, 장의 줄기세포 틈새에 존재하는 p16+ 세포가 관찰되었습니다(그림 1A-C). 

두 번째 노화 마커인 p21의 발현은 일시적 증폭(TA) 세포 틈새와 장의 원주형 세포에서 관찰되었습니다(그림 1E, ,F).F). 이러한 관찰은 동일한 장 부위에서 병변의 지속성이 더 이상 새로운 장 세포를 생성하기 위해 증식 할 수없는 노화 줄기 세포에 기인 할 수 있음을 시사합니다. 

크론병 병변이 회장 말단과 결장 부위에만 발생하는 이유는 아직 밝혀지지 않았습니다. 연구에 따르면 마이코박테리움 아비움 파라투버쿨로시스(MAP) 감염이 크론병의 원인일 수 있다고 합니다.3마이코박테리움 아비움 파라투버쿨로시스는 장의 만성 염증을 시작하고 유지할 수 있습니다. 크론병 병변이 가장 자주 발견되는 장의 교통량이 적은 부위에 마이코박테리움 아비움 파라투베르쿨로시스균이 모여 있는 것이 이에 대한 설명이 될 수 있습니다. 

일단 염증이 시작되면 INF-α, TNF-α, 인터루킨(IL)-6과 같은 전 염증성 사이토카인이 국소 상피 세포 사멸 및/또는 줄기세포 과증식을 유도할 가능성이 있습니다.4 두 가지 측면 모두 상주 줄기세포가 대체 세포를 생성하도록 압력을 증가시키고 줄기세포 풀의 노화를 촉진할 수 있습니다. 노화 세포는 기능 저하 외에도 염증성 사이토카인(IL-6, IL-1, CXCL5, CXCL10, CCL1, CCL2, TNF-α)으로 구성된 노화 관련 분비 단백질체(SASP)를 발현합니다.5 

노화 관련 분비 단백질체 발현은 주변 세포의 노화를 촉진하므로 잠재적으로 병리적인 표현형을 나타냅니다.5 건강한 SG 전구세포 배양에 염증성 사이토카인을 적용했을 때 증식이 유도되었습니다. 장에서도 동일한 효과가 발생한다고 가정하면 크론병의 p16+ 및 p21+ 세포는 인접한 전구 세포에서 복제 노화의 발생을 촉진할 수 있습니다. 염증 환경이 상피 줄기세포, 특히 상피 전구세포에 미치는 영향에 대한 인식이 높아지고 있으며, 이는 염증의 해결뿐만 아니라 상피 완전성 회복을 위한 치료 옵션을 형성하는 데 중요한 역할을 할 것입니다.

FIGURE 1.

The stem and transient amplifying cell niches of the intestine contain potentially senescent cells in Crohn’s disease. In all immunostains, epithelial growth factor receptor (EGFR, brown) is used as a counterstain to provide tissue architecture. (A) H&E staining of intestinal tissue showing characteristic eosin rich cytoplasmic staining (pink) morphology of paneth cells, confirm‎ing localization at level of progenitor cell niche. (B-G) Immunostaining for p16 and p21 (blue) of intestinal tissue from a patient with early Crohn’s disease (B,C,E,F) and age/sex-matched control (D,G). (H) Quantification of p16 and p21 positive cells in progenitor (Prog) and transient amplifying (TA) cell niches in intestinal tissue from early Crohn’s patients (n = 3), compared to age-matched healthy controls (HC). One-tailed Mann Whitney U testing was used for statistical analysis. Exact P-values are given. p16+ or p21+ cells in the progenitor cell niche in the gut were identified based on localization in close proximity to the paneth cells. Methods: Antigen retrieval‎ was performed for 20 minutes with a solution of 1 mM EDTA (pH 8.0) on paraffin sections. Mouse anti-human p16 (Roche clone E6H4, ready to use; blue), mouse anti human p21 (DAKO, clone SX118, 1:20; blue) and rabbit anti-human epithelial growth factor receptor (Abcam clone EP38Y, 1:500; brown) were used with the Lab Vision MultiVision Polymer Detection System anti Mouse-AP anti-rabbit-HRP staining kit (Thermofisher) to detect p16+ and p21+ cells. Arrows denote the progenitor cell niche in the intestine. Triangles denote the transient amplifying cell niche. Intensity of p21 immunostaining in intestine was quantified as pixel intensity.

Go to:

Notes

Author Contribution: XW contributed to the experimental work and data analysis. GD contributed to the patient recruitment and manuscript writing. SP contributed to the study design, data analysis and collection, and first-draft writing.

Supported by: This research was funded by a China Scholarship Council grant (201606220074), Dutch Arthritis Foundation Translational Research grant (T015-052) and a Dutch Arthritis Foundation Long Term Project grant (LLP-29).

Go to:

REFERENCES

1. Pringle S, Wang X, Verstappen GMPJ, et al.. Salivary gland stem cells age prematurely in primary Sjögren’s syndrome. Arthritis Rheumatol. 2019;71:133–142. [PMC free article] [PubMed] [Google Scholar]

2. Wang X, Bootsma H, Terpstra J, et al.. Progenitor cell niche senescence reflects pathology of the parotid salivary gland in primary Sjögren’s syndrome. Rheumatology. (revised manuscript submitted). [Google Scholar]

3. McNees AL, Markesich D, Zayyani NR, et al.. Mycobacterium paratuberculosis as a cause of Crohn’s disease. Expert Rev Gastroenterol Hepatol. 2015;9:1523–1534. [PMC free article] [PubMed] [Google Scholar]

4. Onyiah JC, Colgan SP. Cytokine responses and epithelial function in the intestinal mucosa. Cell Mol Life Sci. 2016;73:4203–4212. [PMC free article] [PubMed] [Google Scholar]

5. Gorgoulis V, Adams PD, Alimonti A, et al.. Cellular senescence: defining a path forward. Cell. 2019;179:813–827. [PubMed] [Google Scholar]