2. OUTLINES
Mast cell ontogeny and tissue localization
Human mast cell heterogeneity
Progress in understanding mast cell functions
Mast cell homeostasis
Interface between innate & adaptive immunity
mast cell in infection
Role in diseases: food allergy, functional GI
disorders, cancer
asthma, other allergic disorders
3. History of mast cell
• Identified as granular cells in mesentery of frog by
Dr von Recklinghausen in 1863
• Dr Paul Ehrlich in 1878 named these cells as
“Mastzellen”
• Initail studies focused on their histological
characteristics, distribution & abundance in health
and dz.
• In 1910, discovery of histamine, In 1938, of slow-
reacting substance of anaphylaxis & In 1966, of
IgE provided initial insights into the role of MCs
in allergic reactions
5. Ontogeny and tissue localization
Human mast cell (MC) originate from
CD34+/CD117+/CD13+ multipotent hematopoietic
progenitor in BM and migrate through blood to
tissue where they mature
In human, detail of their differentiation &
phenotypic diversification are incompletely known
Several studies on mechanism of MCs localization
MC progenitor are abundant in small intestine
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
6. Granulocyte/
macrophage
progenitor
mast cell
progenitor
Common
myeloid
progenitor
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
10. Distribution of mast cell
Fresh camel tissue from 9 healty male
camels (9-12 Mo old) 6 full thickness
section of duodenum, jejunum, ileum
Either fixed in 10% phosphate-buffered
formaldehyde over night or in Carnoy’s
fluid for 4 hrs serial section at thickness
of 4 m
-1 section of each was stained with H&E
for histopathological evaluation
-other sections were stained by
1.Metachromatic staining : MB
2.immunohistochemistry : mouse Ab to
human tryptase
M.B. Al-Aghoul et al. Euro J Histochemistry 2008; 52(4): 237-42
11. Distribution of mast cell
M.B. Al-Aghoul et al. Euro J Histochemistry 2008; 52(4): 237-42
12.
13. M.B. Al-Aghoul et al. Euro J Histochemistry 2008; 52(4): 237-42
-no significant difference
was observed in MC
among lamina propria,
muscularis mucosae,
muscularis externa &
serosa
-only significant
difference observed was
in submucosa region
1.highest MC in
jejunual submucosa
2.lowest MC in ileal
submucosa
15. Ontogeny and tissue localization
Localization to small intestine reliant on
oAdhesive interaction which is controlled by
- 4 (CD49d) 7 integrin
-vascular cell adhesion molecule 1
(VCAM-1:CD106)
-mucosal addressin cell adhesion
molecule 1 (MAdCAM-1)
oExpression of CXCR2 (CD182) is critical
for localization of MC progenitors in gut
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
16. Ontogeny and tissue localization
MC progenitor are not abundant in lung
Pulmonary inflammation increased numbers of
MC are detected in bronchial epithelium, airway
smooth muscle
Localization to lung
o Adhesive interaction
-Vascular cell adhesion molecule 1
- 4 7 or 4 1 integrin
but not mucosal addressin cell adhesion
molecule 1
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
21. Progress in understanding mast
cell functions : homeostasis (1)
MC’s mediator influence many sites involved in
All phase of wound healing
Acute inflammatory
Promote influx of inflammatory cells to injury site
Proliferative phase
Re-epithelialization & angiogenesis
Release many angiogenic factors to induce revasculaization of
damage tissue
Heparin from MC stimulates endothelial cell migration to form
new blood vessel
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
22. Progress in understanding mast
cell functions : homeostasis (2)
All phase of wound healing
MC tryptase stimulates vessel tube formation &
enhances growth of microvascular endothelial cells
MC chymase promotes angiogenesis through
effects of angiotensin II
Generate growth factors : fibroblast growth factor,
vascular endothelial growth factor (VEGF), platelet-
derived growth factor (PDGF), nerve growth factor
(NGF)
all growth factors induce proliferation of
epithelial cells & fibroblasts
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
23. Progress in understanding mast
cell functions : homeostasis (3)
All phase of wound healing
Remodeling phase
As fibroblast expand in previous phase, they deposit
collagen & other extracellular matrix proteins molded and
remodeled into scar tissue
Hair follicle recycling
MC histamine, TNF, substance P involved are
thought to contribute in hair follicle recycling (where
hair growth & regression continuously occur)
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
24. Progress in understanding mast
cell functions : homeostasis (3)
Bone remodeling
MC-deficient mice have femurs that are lighter &
thinner than WT mice be validated with MC
reconstituted mice
MCs are source of osteopontin, glycoprotein
component of bone matrix, that contributes to bone
resorption & calcification (mechanism of bone
remodeling)
In human systemic mastocytosis, bone turnover is
accelerated enhance bone loss
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
25. Mechanism of angiotensin II in
angiogenesis (1)
First :
increasing vascular endothelial growth factor
(VEGF) and basic fibroblast growth factor (bFGF)
synthesis
But angiogenic response to VEGF might involve the
production of nitric oxide (NO) by increasing
expression of both endothelial (eNOS) and inducible
(iNOS) NO synthase
bFGF modulate eNOS level and NO production
leading to endothelial cell differentiation into
vascular tubes
Radia Tamarat et al. Lab Invest 2002, 82:747–756
26. Mechanism of angiotensin II in
angiogenesis (2)
second :
By regulating matrix metalloproteinases
(MMP) production and activation
2 members of MMP endopeptidase family,
MMP-9 (92 KD) and MMP-2 (72 KD), are
able to degrade extracellular matrix
components of basement membrane
(proteins that keep the vessel walls solid)
This proteolysis allows the endothelial cells
to escape into the interstitial matrix
Radia Tamarat et al. Lab Invest 2002, 82:747–756
27. Mechanism of angiotensin II in
angiogenesis (3)
Third :
exerts several direct effects to
stimulation of monocyte recruitment,
activation of M , and enhanced COX-2
protein expression
Radia Tamarat et al. Lab Invest 2002, 82:747–756
29. mast cell functions : interface between
innate & acquired immunity
Various pathogen & their products activate MCs
through TLRs, complement Rc, Fc Rc
o In early phase, MCs release performed mediators that
recruit effector cells ( e.g. Neutrophil) to clearance of
pathogen
o Activate DCs & T cells and their migration to LN
o Increasing evidence that function as APC (express
MHC class I and upregulate expression of MHC class II
when stimulated with IFN- , TNF, LPS)
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
31. mast cell functions : interface between
innate & acquired immunity
In addition to MHC
o Costimulatory molecules CD28, CD80, CD86,
intercellular adhesion molecule-1, OX-40 ligand (act on
T cells) and CD40 ligand (act on B cells) are also
expressed on MCs
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
32. mast cell in infection
Helminth infection
MC degranulation influence DC activation of T cells
away from Th1, toward Th2 response (mechanism of
this function due to PGD2 or histamine which can
suppress IL-12 release by DC)
MCs are actvated by helminth & MC hyperplasia is
observed in helminth infection
but critical involvement in pathogenesis has shown in
few types of these infection e.g. trichinella spiralis is
expulsed by MC-derived MMCP-1, TNF, IL-4. Nippostrongylus
brasiliensis also induces MC hyperplasia
Middleton’s Allergy Principle & Practice 7th ed
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
33. mast cell in infection
Bacterial infection
MC-derived TNF, together with LTC4 & LTB4
contributed to recruitment neutrophils to clearance
Klebsiella pneumoniae, Listeria monocytogenes,
Pseudomonas aeruginosa
MC can produce antimicrobial nets containing
proteases and LL37 (Cathelicidin antimicrobial peptide
,polypeptides found in lysosomes in macrophages and
polymorphonuclear leukocytes (PMNs))
Further studies are needed to completely understand
Middleton’s Allergy Principle & Practice 7th ed
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
34. mast cell in infection
Fungal infection
Animal MCs respond to yeast cell wall zymosan and
peptidoglycan by releasing cysteinyl LT & by production of
ROS
Human MCs respond to zymosan, but not peptidoglycan,
through dectin-1, -glucan Rc for C-type lectin family
Trichoderma viridae, indoor fungus, induce MC
degranulation (high dose) but low dose enhance histamine
secretion from MCs
Aspergillus fumigatus induce IgE-independent MC
degranulation
In vivo requires additional study
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
35. mast cell in infection
Viral infection
This aspect is emerging field
Report from HIV-infected patients
Increased serum IgE & higher levels predict worse prognosis
Israël-Biet D et al.JACI 1992 Jan;89:68-75
Fewer MCT in intestinal mucosa of patients with
AIDSindicate a role for functional T lymphocytes in the
development of the T mast cell type in humans
Irani AM et al. J Immunol. 1987; 138(12): 4381-6
36. mast cell in infection
Viral infection (2)
Dengue virus can activate MCs to release IL-1 , IL-6,
RANTES, MIP-1 and MIP-1
Dengue virus also induce caspase-dependent MC
apoptosis, but not apoptosis of other Fc -expressing cell
types
Respiratory syncytial virus (major cause of LRT in infant &
associated with development of asthma later in life
MD density and levels of LT are increasesed in lungs of this
infected rat implicating MCs in response to this viral
infection
Airway MC numbers increase in parainfluenza infection
37. mechanism of MC responses to pathogens
TC Moon et al.Mucosal Immunology 2010; 3(2):111-128
39. intestinal mast cells regulate GI tissue homeostasis
Stephan C. Bischoff. Semin Immunopathol 2009; 31: 185-205
40. Role in disease : food allergy(1)
Increased intestinal permeability is common
outcome of immune-mediated dz. Including DM,
IBS, food allergy, celiac dz.
Contribution of MC to barrier functions in
homeostasis is not well defined, mediators which
effect on epithelial barrier function including
histamine, proteases, IL-4, IL-13, TNF- , IL-1
Exposure to human MC chymase increased cultured
epithelial cell permeability providing support role of
chymase in regulation barrier function
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
41. Role in disease : food allergy(2)
Infiltration of MC to mucosal site of small or large
intestine following oral challenge is common
feature observed in all food allergies
May associated with constipation
Number of MC & their proximity to nerve fibers is significantly
reduced by removal of allergen from diet in children suffering
from chronic constipation
MC influence intestinal smooth muscle function as a result of
their close approximation with enteric nerve
Histamine, tryptase, LTs directly cause smooth muscle
contraction / relaxation
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
42. Role in disease : food allergy(3)
Cell adhesion molecule-1 (CADM1) promote
communication between nerves or smooth muscle
and MC
May associated with diarrhea
sphingosine 1-phosphate (S1P) was identified as
potential therapeutic target for allergy-induced
diarrhea due to
• There has report that FTY720 (inhibitor of S1P
signaling) can reduce MC infiltration to large
intestine
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
43. Role in disease : food allergy(4)
sphingosine 1-phosphate (S1P) cont.
• S1P is blood borne lipid mediator regulates
angiogenesis, vascular stability, and
permeability
• In immune system, it is now recognized as a
major regulator of trafficking of T- and B-cells
• S1P interaction with its receptor S1PR1 is
needed for the egress of immune cells from the
lymphoid organs (such as thymus and lymph
nodes) into the lymphatic vessels,
• S1PR1 highly expression in endothelial cell
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
44. Role in disease : food allergy(5)
Prominent result of MC/nerve/smooth muscle
interaction is hypersensitivity of nerves resulting
in elevated smooth muscle contractility
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
45. Role of mast cells in intestinal allergy
Stephan C. Bischoff. Semin Immunopathol 2009; 31: 185-205
46. Role in disease : functional
GI disorders (1)
Diagnosis of IBS is based on symptoms due to
absence of specific pathology
Common feature of IBS is visceral hypersensitivity
from stimuli in lumen of gut
Chronic stress caused release of norepineprine
lesd to increased expression of nerve growth
factor (product of MC) key role in sensitizing
visceral afferent neurons
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
47. Role in disease : functional
GI disorders (2)
IBS can be classified as
diarrhea-predominant (IBS-D)
constipation-predominant (IBS-C) or IBS with
alternating stool pattern (IBS-A)
In some individuals, IBS may have acute onset and
develop after infectious illness characterized by two or
more of the following:
fever, vomiting, diarrhea, or positive stool culture
This post-infective syndrome has been termed "post-infectious
IBS" (IBS-PI)
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
48. Role in disease : functional
GI disorders (3)
In IBS-PI, there is evidence that several
inflammatory cells are elevated e.g. MC, (5-HT)-
containing enterochromaffin cells(EC), T cells
In small cohort study, control groups were
compared with non IBS-PI and IBS-PI
Non IBS-PI, there were elevated levels of 5-HT-
containing EC cells & intraepithelial lymphocytes
IBS-PI, demonstrated elevated number of MC & 5-HT-
containing EC cells MC are important component as
distinguishing feature of IBS-PI
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
49. Role in disease : functional
GI disorders (4)
Enterochromaffin (EC) cells (Kulchitsky cells) are
type of enteroendocrine cell occurring in the
epithelia lining lumen of the digestive tract and the
respiratory tract
produce and contain about 90% of body's store of
serotonin (5-HT)
called “entero” meaning related to gut & “chromaffin”
because of chromium salt reaction that they share with
chromaffin cells of the adrenal medulla (adrenal glands)
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
50. Role in disease : functional
GI disorders (5)
5-HT is important in response to chemical, mechanical
or pathological stimuli in the lumen
It activates both secretory and peristaltic reflexes
activates vagal afferents (via 5-HT3 receptors) that signal to
brain (important in the generation of nausea)
Ondansetron is antagonist of 5-HT3 receptor and is an
effective anti-emetic.
Another population of chromaffin cells is found only in
stomach wall, called enterochromaffin-like cells (ECL)
look like EC cells but do not contain 5-HT
produce Gastrin at antrum of stomach.
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
51. Role in disease : functional
GI disorders (6)
IBS-D pts. have significantly elevated MC
numbers in jejunum with corresponding higher
levels of MC tryptase indicating that mucosal
inflammation of IBS is not restricted to lower gut
MC tryptase activated protease-activated-
receptor-2 (PAR2)
PAR2 is expressed on epithelial, smooth
muscles , nerves, MC, APC
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
52. Role in disease : functional
GI disorders (7)
PAR2 is expressed on epithelial, smooth muscles
, nerves, MC, APC
In IBS-C, it was found increasing numbers of MC in
duodenum
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
53. Role in disease : cancer(1)
Gounaris et al.’s work found that
Colon cancer develop from nonmalignant adenomatous
polyps
MC is an essential hematopoietic component in polyp
development
Genetic or pharmacologic depletion of MC resulted in
remission of polyps
Treg, which expand in adenomatous polyp
no longer produce IL-10 (IL-10 suppress inflammation which
critical component of tumor progression)
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
54. Role in disease : cancer(2)
And same time not suppress mastocytosis (normally Treg will
suppress MC activity via IL-10)
Switch from producing IL-10 to IL-17 promoting
proinflammatory rather than immunosuppressive environment
MC were recruited by “IL-17 switched” Treg cells,
further increasing proinflammatory environment
Terez She-Donohue et al. Curr Gastroenterol Rep 2010; 12: 349-57
55. Take Home Messages
Mast cells are functionally diverse cells that have
a constitutive presence at mucosal surfaces and
elaborate impressive array of mediators, making
them an attractive therapeutic target
mast cell proteases,their well-documented ability
to alter intestinal permeability, a key factor in
several GI autoimmune/inflammatory pathologies
56. Take Home Messages
role of mast cells in IBS and food allergy is well-
documented and represents a convergence of
mast cell actions on immune and intestinal
functioneral GI autoimmune/inflammatory
pathologies
Role of mast cells in human needs further studies