Gut permeability: esp. to Del

[Guest guest]

>

Since we are talking about food allergies and gut permeability,

I thought you might appreciate this. A lot of research is being done

on how gut permeability is affected by foods and bacteria ... Del,

your kefir may have been what was keeping yours from being

leaky. Roy Jamron does a lot of thinking about this stuff and

posts on the celiac group (and doesn't mind being disseminated).

Anyway, they are working on coming up with a drug that inhibits

zonulin and so decreases the permeability problem. Sounds like

L. paracasei works pretty well too.

-- Heidi Jean

===========

>Move over Dr. Fasano... It seems Dr. Fasano is not alone in studying

>intestinal permeability and its relation to autoimmune diseases. The

>following March 2005 International Journal of Molecular Medicine looks at

>tight junction proteins (including zonulin) and Crohn's disease. Even more

>interesting is the involvement of transforming growth factor, TGF-beta, in

>regulating permeability. That got me thinking. I have previously

>discussed the how levels of TGF-beta1 and Th3 helper T cells affect food

>allergies and celiac disease, and that probiotic strains of the bacteria,

>L. paracasei, can stimulate Th3 cell generation, increase TGF-beta1 levels,

>and reduce allergies. See:

>

>http://maelstrom.stjohns.edu/CGI/wa.exe?A2=ind0501e & L=celiac & P=2666

>http://maelstrom.stjohns.edu/CGI/wa.exe?A2=ind0502a & L=celiac & P=164

>http://maelstrom.stjohns.edu/CGI/wa.exe?A2=ind0502a & L=celiac & P=9694

>http://maelstrom.stjohns.edu/CGI/wa.exe?A2=ind0502a & L=celiac & P=9818

>

>Further research, focusing on sperm production, looks at Sertoli cell tight

>junctions that constitute the blood-testis barrier. TGF-beta3 is shown to

>regulate the permeability of this tight junction, possibly by inhibiting

>zonulin. (See abstracts below.)

>

>So, can regulating and altering levels of TGF-beta proteins inhibit zonulin

>in the same way as AT-1001 to achieve a reduction of " leaky gut " ? Or, in

>other words, can a probiotic achieve the same effect as AT-1001 to inhibit

>zonulin? This might save us a fortune in pharmaceutical costs...

>

>----------

>Int J Mol Med. 2005 Mar;15(3):407-10.

>

>Dislocation of tight junction proteins without F-actin disruption in

>inactive Crohn's disease.

>

>Oshitani N, Watanabe K, Nakamura S, Fujiwara Y, Higuchi K, Arakawa T.

>

>Third Department of Internal Medicine, Osaka City University Medical

>School, Abeno-ku, Osaka 545-8585, Japan. nobu@...

>

>Crohn's disease is associated with increased permeability of the intestinal

>barrier even in quiescent patients. Increased intestinal permeability may

>cause dysregulated immunological responses in the intestinal mucosa that

>leads to chronic intestinal inflammation. We have studied the expression of

>tight junction proteins (occludin and zonula occludens), alpha2-smooth

>muscle actin, TGF-beta with a cytoskeletal protein (F-actin) in the

>intestinal epithelium of patients with inflammatory bowel disease. Surgical

>samples were obtained from 6 controls (individuals without inflammatory

>bowel disease), 8 patients with ulcerative colitis and 7 patients with

>Crohn's disease. F-actin was visualized with fluorescein phalloidin. Tight

>junction proteins, alpha2 smooth muscle actin, and TGFbeta were visualized

>by the immunofluorescent method. Occludin and zonula occludens found in

>apical tight junctions in normal epithelium were dislocated to the

>basolateral position and in the lamina propria extracellular matrix in

>patients with Crohn's disease, while the structure of F-actin was

>maintained in inactive or minimally inflamed mucosa. TGF-beta positive

>inflammatory cells were increased in ulcerative colitis and Crohn's disease

>mucosa. Subepithelial myofibroblasts were constitutively found in controls,

>ulcerative colitis, and Crohn's disease mucosa. Latent dislocation of tight

>junction proteins, without disturbance of the cytoskeleton in the inactive

>mucosa of patients with Crohn's disease, may permit the invasion of gut

>antigens because the functional disruption of tight junctions could

>initiate an altered immune response.

>

>PMID: 15702229 [PubMed - in process]

>

>----------

>J Cell Biol. 2003 Dec 22;163(6):1303-11.

>

>Free full text:

>http://www.jcb.org/cgi/content/full/163/6/1303

>

>TGF-beta receptor kinase inhibitor enhances growth and integrity of

>embryonic stem cell-derived endothelial cells.

>

>Watabe T, Nishihara A, Mishima K, Yamashita J, Shimizu K, Miyazawa K,

>Nishikawa S, Miyazono K.

>

>Department of Molecular Pathology, Graduate School of Medicine, The

>University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

>

>Recent findings have shown that embryonic vascular progenitor cells are

>capable of differentiating into mural and endothelial cells. However, the

>molecular mechanisms that regulate their differentiation, proliferation,

>and endothelial sheet formation remain to be elucidated. Here, we show that

>members of the transforming growth factor (TGF)-beta superfamily play

>important roles during differentiation of vascular progenitor cells derived

>from mouse embryonic stem cells (ESCs) and from 8.5-days postcoitum

>embryos. TGF-beta and activin inhibited proliferation and sheet formation

>of endothelial cells. Interestingly, SB-431542, a synthetic molecule that

>inhibits the kinases of receptors for TGF-beta and activin, facilitated

>proliferation and sheet formation of ESC-derived endothelial cells.

>Moreover, SB-431542 up-regulated the expression of claudin-5, an

>endothelial specific component of tight junctions. These results suggest

>that endogenous TGF-beta/activin signals play important roles in regulating

>vascular growth and permeability.

>

>PMID: 14676305 [PubMed - indexed for MEDLINE]

>

>----------

>Endocrinology. 2001 May;142(5):1865-77.

>

>Free full text:

>http://endo.endojournals.org/cgi/content/full/142/5/1865

>

>Transforming growth factor-beta3 perturbs the inter-Sertoli tight junction

>permeability barrier in vitro possibly mediated via its effects on

>occludin, zonula occludens-1, and claudin-11.

>

>Lui WY, Lee WM, Cheng CY.

>

>Population Council, Center for Biomedical Research, New York, New York

>10021, USA.

>

>Throughout spermatogenesis, inter-Sertoli tight junctions (TJs) that create

>the blood-testis barrier in the rat must be disassembled and reassembled to

>permit the timely passage of preleptotene spermatocytes from the basal to

>the adluminal compartment of the seminiferous epithelium. However, the

>mechanism(s) and the participating molecules that regulate this event are

>largely unknown. Although there is no in vitro model to study the event and

>regulation of inter-Sertoli TJ disassembly, primary cultures of Sertoli

>cells in vitro can be used to study junction assembly. In this study, we

>sought to investigate whether cytokines are involved in the inter-Sertoli

>TJ assembly in vitro. Sertoli cells isolated from 20-day-old rats were

>cultured at a density of 0.5-1.2 x 10(6) cells/cm(2) on Matrigel-coated

>dishes or bicameral units for 8-9 days. The steady-state messenger RNA

>levels of basic fibroblast growth factor (bFGF), transforming growth factor

>(TGF)-beta2, and TGF-beta3 at different time points were assessed by

>semiquantitative RT-PCR. In selected experiments, the assembly of inter-

>Sertoli TJs was monitored by transepithelial electrical resistance

>measurement. It was found that there was no change in the expression of

>basic fibroblast growth factor throughout the entire culture period.

>However, there was a 2-fold reduction in the expression of TGF-beta2 and

>TGF-beta3 at the time inter-Sertoli TJs were being assembled. On days 5-8,

>after the inter-Sertoli TJs had been assembled, the Sertoli cell steady-

>state messenger RNA levels of TGF-beta2 and TGF-beta3 increased by as much

>as 3- and 6-fold, respectively, when compared with Sertoli cells on days 1-

>3 when TJs were being assembled. Also, it was found that recombinant TGF-

>beta3 added to Sertoli cells cultured in vitro at 1.2 x 10(6) cells/cm(2)

>on Matrigel-coated bicameral units perturbed the inter-Sertoli TJ

>permeability barrier dose-dependently. Moreover, the presence of TGF-beta3

>also inhibited the transient and/or basal expression of several TJ-

>associated proteins, which include occludin, zonula occludens-1, and

>claudin-11 when inter-Sertoli TJs were being assembled in vitro. These

>results suggest that TGF-beta plays a crucial role in regulating the

>complicated biochemical events of junction assembly in the testis.

>

>PMID: 11316752 [PubMed - indexed for MEDLINE]

>

>----------

>Biol Reprod. 2003 May;68(5):1597-612. Epub 2002 Nov 27.

>

>Free full text:

>http://www.biolreprod.org/cgi/content/full/68/5/1597

>

>Transforming growth factor beta3 regulates the dynamics of Sertoli cell

>tight junctions via the p38 mitogen-activated protein kinase pathway.

>

>Lui WY, Lee WM, Cheng CY.

>

>Population Council, Center for Biomedical Research, New York, New York

>10021, USA.

>

>Earlier studies have implicated the significance of transforming growth

>factor-beta3 (TGFbeta3) in the regulation of Sertoli cell tight junction

>(TJ) dynamics, possibly via its inhibitory effects on the expression of

>occludin, claudin-11, and zonula occludens-1 (ZO-1). Yet the mechanism by

>which TGFbeta3 regulates the Sertoli cell TJ-permeability barrier is not

>known. Using techniques of semiquantitative reverse transcription-PCR (RT-

>PCR), immunoblotting, immunohistochemistry, and inhibitors against

>different kinases coupled with physiological techniques to assess the

>Sertoli cell TJ barrier function, it was shown that this TGFbeta3-induced

>effect on Sertoli cell TJ dynamics is mediated via the p38 mitogen-

>activated protein (MAP) kinase pathway. First, the assembly of the Sertoli

>cell-TJ barrier was shown to be associated with a transient but significant

>decline in both the TGFbeta3 production and expression by Sertoli cells.

>Furthermore, addition of TGFbeta3 to Sertoli cell cultures during TJ

>assembly indeed perturbed the TJ barrier with an IC50 at approximately 9

>pM. Second, the TGFbeta3-induced disruption of the TJ barrier was

>associated with a transient induction in MEKK2 but not the other upstream

>signaling molecules that mediate TGFbeta3 action, such as Smad2, Cdc42,

>Rac2, and N-Ras, suggesting this effect might be mediated via the p38 MAP

>kinase pathway. This postulate was confirmed by the observation that

>TGFbeta3 also induced the protein level of the activated and phosphorylated

>form of p38 MAP kinase at the time the TJ barrier was perturbed. Third, and

>perhaps the most important of all, this TGFbeta3-mediated inhibitory effect

>on the TJ barrier and the TGFbeta3-induced p-p38 MAP kinase production

>could be blocked by SB202190, a specific p38 MAP kinase inhibitor, but not

>U0126, a specific MEK1/2 kinase inhibitor. These results thus unequivocally

>demonstrate that TGFbeta3 utilizes the p38 MAP kinase pathway to regulate

>Sertoli cell TJ dynamics.

>

>PMID: 12606350 [PubMed - indexed for MEDLINE]

>

>* * *

>

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Heidi Jean