angiogenesis in viral immunoinflammatory lesions
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Angiogenesis in Viral Immunoinflammatory Lesions. Barry T. Rouse University of Tennessee Part 1. The Smokies’ Lost Tribe. “Of course we do not have herpes”. Herpetic Stromal Keratitis. - PowerPoint PPT PresentationTRANSCRIPT
Angiogenesis in Viral Immunoinflammatory
Lesions
Barry T. RouseUniversity of Tennessee
Part 1
The Smokies’ Lost Tribe
“Of course we do not have herpes”
Herpetic Stromal Keratitis
An immunoinflammatory reaction in the eye that appears to represent a Type 1 CD4+ T cell mediated reaction in a tissue, the cornea, that normally lacks a vascular system and has been considered as one site of immunological privilege.
HSV Keratitis in humans
• Most common infectious cause of blindness in USA
• At least 400,000 cases
• About 20% of cases have the immunoinflammatory stromal form
• Requires chronic treatment and may lead to corneal transplantation
Pathogenesis of Stromal Keratitis
• Complex involves multiple humoral and cellular participants
• Neovascularization a major feature
• Principal orchestrators of the lesion are CD4+ T cells of the type 1 phenotype
HSK is caused by CD4+ type 1 T cells but IL-12 expression in the eye prior to HSV infection
diminishes rather than exaggerates the lesions.
-Lee et. Al. 2002
0
25
50
75
100
0 5 10 15 20
IL-12 DNAvector DNA
0
1
2
3
4
5
0 5 10 15 20
Expression of IL-12 DNA prior to infection inhibits HSK severity and incidence
Inci
den
ce (
%)
Sev
erit
y
Days post infection
How does the IL-12 effect function?
• Antiviral effect via IFN- - No
• Immunosuppression via iNOS - No
• Modulation of immunity - No
• Indirect effect on angiogenesis
-actin
IP-10
IFN-
MIG
IL-10
Gene expression in cornea at day 3 post infection by RT PCR
BALB/c GKO
naive
Virus
+ ve
ctor
Virus
+ IL
-12
Virus
+ ve
ctor
Virus
+ IL
-12
0
5
10
15
20
An
gio
gen
ic s
cori
ng
0 5 10 15 20
Days post infection
IL-12 DNAIP-10 DNAvector DNA
IL-12 and IP-10 DNA both inhibit ocular angiogenesis
IL-12 DNA effect reversed by anti IP-10 + anti MIG
INTERPRETATION
IL-12 expression causes upregulation via IFN- induction of IP- 10 (and MIG).
These chemokines bind to heparan sulfate and block the angiogenic effect of FGF.
Consequence : inhibited angiogenesis which could be necessary to develop stromal keratitis following virus infection.
• Which molecules are induced in the cornea that can account for HSV-driven neovascularization?
• Is preventing angiogenesis a logical therapeutic goal for herpetic keratitis?
Viruses- neovascularizationVirus Lesion Mechanism
HHV8 Kaposi’s Sarcoma
Encodes multiple angiogenic proteins
HBV Hepatitis Activates HIF-1a that turns on VEGF promoter
HIV Kaposi’s Sarcoma
Tat activates VEGF-R2
HPV Cervical Cancer Increases VEGF via indirect complex mechanism
HSV Herpetic Stromal Keratitis
Mysterious but unraveling
Productive Infection By HSV
• Most host mRNA and protein synthesis rapidly shut down
• A few host proteins are made and secreted. These include IL-1 and IL-6.
• To continue open the Part 2
• from Supercourse-Vet
• htpp://centaur.vri.cz