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Sjogren’s Syndrome: Pathogenesis and New Directions for Therapy
Robert I. Fox, M.D., Ph.D.
Carla M. Fox, R.N.
Scripps Memorial Hospital
Scripps Memorial/XiMED
La Jolla, California
Goals-1
Recognize that:• Sjogren’s has benign symptoms (dry
eyes/mouth), fatigue, myalgias and cognitive impairment.
• These symptoms are are the largest factor in patient “disability”– although not well treated by either local or biologic therapy.
Goals-2
• Systemic manifestations (rash, arthritis, myositis, lymphoproliferative, biomarkers)
• These respond much better to systemic therapy.
• Targets correspond to genes identified in genomic screens.
• Characteristic cytokine, mRNA and gene methylation/acetylation maps.
Goals-3
• The ability to improve extraglandular manifestations but not “pain/cognitive” indicates that we are missing an important nociceptive pathway.
• New advances in neuroprotection in Multiple Sclerosis provide new opportunities to target microglial cells
Roadblocks to Treatment of Dry Eyes and Dry Mouth
• Problems with study design
• Poor correlation with objective clinical and laboratory values
• Concept of “functional circuit” not recognized by immunologists or Pharma—while it is the basis for neurologists and pain therapy
Goals for TherapyFatigue, Myalgias and Cognitive Impairment
• This is the “holy grail” of neuro-immunology to solve in the next decade.
• Flu-like symptoms, “ jet lag,” or after treatment of hepatitis C with IFN.
• We have animal models from duloxetene (now for back pain) or modafinil (jet lag)
• Molecular targets such as mTOR and AKT need to be considered.
Fatigue and Cognitive Impairment
• Much more common in SS or SLE
than in RA -
What is that telling us about pathogenesis? • Involves the neuro-endocrine-immune axis
associated with “stress” response
(hypothalamic-adrenal axis)
which we must add
to innate and acquired responses as targets
Background-1The functional Circuit
• To understand “benign symptoms” and develop better therapies—we must review the concept of the functional circuit in SS
• the interaction of immune activation on microglial cells and associated neurons
• New targets include mTor and AKT pathways
Background-2The functional circuit in SS
1. Mucosal Surface(inflammatory cytokines and metalloproteinase)
1. Mucosal Surface(inflammatory cytokines and metalloproteinase)
2. MidbrainVth Nucleus(lymphocytes and glial cells)
2. MidbrainVth Nucleus(lymphocytes and glial cells)
4. Gland(lymphs, cytokines, metalloproteinase)
4. Gland(lymphs, cytokines, metalloproteinase)
3. Vascular(iNOS, CAMs, Chemokines)
3. Vascular(iNOS, CAMs, Chemokines)
BrainCortex
Nociception (pain)glial cells and
corticcal neurons
BrainCortex
Nociception (pain)glial cells and
corticcal neurons
These sites and their cytokines correlate with systemic manifestations
We must understand these sites to treat “benign” symptoms
Does this apply to Sjogren’s syndrome?
• Patients with early SS had corneal pain that decreased completely with topical anesthesia*
• Patients with chronic SS showed only a partial (30% decrease) in eye pain after topical anesthetic*
• Functional MRI (fMRI) showed nocioceptive pattern—called phantom pain amplification
*Rosenthal et al
To study the mechanism of neurogenic or nociceptive pain we must use animal model-1
• The thrombospondin (-/-) mouse (TSP null) or the TGF-receptor mutation both develop SS like disease
• The mouse develops both oral and ocular lesions
• The mouse develops ANA and SS-A antibodies
• Thrombospondin is a matrix protein that plays a role in activation of latent TGF-
• Activated TGF-promotes Treg and inhibits Th-17 (IFN-• Thus, TSP (null) has high levels of Th-17, IL-17 and IFN-
Thrombospondin (-/-) mouse model of SS
4 wks
Lacrimal gland biopsies
The mouse has ANA+, SS-A+TSP null can not activate TGF-In absence TGF-continuous Th-17TGF- and cytokine activation stimulates mTor/AKT
WT
Tsp-/-
24 wks
At the level of the Vth nerve(Tsp -/- mouse)
• Microglial cells translate inflammatory signals that go to nociceptive cortex
WT TSP (-/-)
mTor and AKT activated in response to “lower stimuli”in the tsp (-/-) mouse
0
Neuroplasticity in Pain Processing1-3
1. Woolf CJ, Salter MW. Science. 2000;288:1765-1768. 2. Basbaum AI, Jessell TM. The perception of pain. In: Kandel ER, et al, eds.
Principles of Neural Science. 4th ed. 2000:479.3. Cervero F, Laird JMA. Pain. 1996;68:13-23.
Stimulus Intensity
100
Pain state Normal
Allodynia
Hyperalgesia3
80
60
40
20
innocuous noxious
Pa
in S
en
sa
tio
n
Thrombospondin (-/-)Mouse at 24 wksWhere a trivial stimuliCauses pain response
Wild type
A pain stimuli that is innocuous in Wild Typedoes cause nociceptive pain in tsp (-/-) mouse model
The Pain Threshold is Lowered in the Tsp (-/-) mouse
•Ocular chemical stress model of nociceptive pain•Le Bars D, Animal models of Nociception. Pharmacological reviews 2001;53:597-652.
Moulton et*. Al used fMRI in SS patients with chronic ocular painusing fMRI of nociceptive pain have been studied
Cortical regions that activate with ocular pain signal at “benign stimuli levels” occur only in chronic SS patients with severe pain
*Moulton EA, Becerra L, Rosenthal P, Borsook D. An Approach to Localizing Corneal Pain Representation in Human Primary Somatosensory Cortex. PloS one 2012;7:e44643.
EmotionalEmotional PhysiologicalPhysiological
Similar pattern ofFos-ir in PVH neurons
in response to distinct stressors
Neuroinflammation plays a prominent role in the pathophysiology of several neurodegenerative disorders, including Multiple Sclerosis and Sjogren’s syndrome.
Microglia contribute to initiating and maintaining brain inflammation, and once activated release pro-inflammatory mediators potentially cytotoxic, like nitric oxide (NO)
mmt
mTor and AKT pathway have multiple targets for drug screening
in response to cytokines screening
mTOR inhibitors reduced NOS activity and NOS2 expression induced by cytokines, but not those induced by LPS.
In conclusion, mTOR selectively controls microglial activation in response to pro-inflammatory cytokines and appears to play a crucial role in microglial viability
Review of Sjogren’s Systemic
• From the point of view of rheumatologist
EYE DRYNESS results in the clinical appearance of keratoconjunctivitis sicca (KCS)characteristic of Sjogren’s Syndrome
The upper lidliterally sticks to theEpithelial surface and pulls surfacemucin layers off. The Rose Bengal dye retention test
is like “rain water pooling in a street pothole”
This test can be done at bedside
and allows“triage” and rapid referral of patientsto Ophthalmology
Severe “Xerostomia” (dry mouth) with dry tongue
Angular cheilitis
(candida)
Therapy of “benign” symptomsa. dry eyesb. painful eyesc. dry mouthd. painful mouthe. fatiguef. myalgias
Symptomatic and objective findings are poorly correlated.
For this audience, I will not review the myriad of
artificial tears and salivas. I review these on my website (in downloadable files for patients) to facilitate providing information
to patients.
robertfoxmd.com
Simple Reminders:a. artificial salivas or
secretagogues will not work until you treat the oral candida first.
b. artificial tears with preservatives cannot be used more than
4 times a day,and will not work
until you treat blepharitis
Cortical Map for Corneal Pain
Figure 3
Hypothalamic Axis
• We also know from the high frequency of autonomic dysfunction, that we have not yet influenced the secondary effects on the hypothalamic axis.
• We know that prednisone works, but we can not therapeutically obtain the same benefit in SS from other medications.
Extraglandular Manifestations
• May be Lupus-like (immune complex)-pleurisy, hemolytic anemia, ITP, vasculitis
• May be lymphocytic infiltrate-
Interstitial pneumonitis, RTA, lymphoma,
neuropathy (central nervous or peripheral)
• Measured by ESSDAI scale (weighted by importance)
Therapyfor
Extraglandular Manifestations
• Manifestations correlate with acute phase reactants and biomarkers
• Manifestations respond to systemic therapy such as rituximab, abatacept, belumimab, anti-CD22 (epratazumab)
Sjogren’s Syndrome – with parotid enlargement indicates lymphoproliferative tendency
Scleritis (vasculitis)
But in today’s “super speed medicine”
• Not everything is so simple
• Caution that it is not a simple systemic manifestation of SS
Ulcerative keratitis(in patient given broad spectrum antibiotic
plus anesthetic)
Not all rashes are disease flares
Patient with NSIP who developedpneumocystis on therapy
Steps in Pathogenesis
• Homing to specific tissues (glands)
• Production of autoantibodies
• Pathogenesis of salivary gland lesions
A key “target” in Sjogren’s is that lymphocytes “home” to the glands
1. Lymphocytes have surface “homing receptors”
when generated in node or marrow.
CD4+CD4+
B cellB cell
BloodBlood
3. When the homing receptor encountersvascular adhesive molecules,the lymphocyte enters tissue.
2. Lymphs migrate through blood
to tissues.
Interfere with homing (obligate apoptosis if not bind “addressin”)
• Natalizumab (Tsabri)- cell adhesion a4-integrin• Odulimomab (ICAM, CD54, LFA-1)-
adhesion and migration• Fingolimod (Gilenya)-
sphingosine-1 receptor• CD22 (Epratazumab)
In Sjogren’s Syndrome,many acini and ducts are spared
Sjogren’s Normal
Gene expression profiling of minor salivary glands clearly distinguishes primary Sjögren's syndrome patients from healthy control subjects
Arthritis & RheumatismVolume 52, Issue 5, pages 1534-1544, 5 MAY 2005 DOI: 10.1002/art.21006http://onlinelibrary.wiley.com/doi/10.1002/art.21006/full#fig1
Time course of autoimmune response*
1. Genetic factors predispose to Sjogren’s2. Environmental factors such as a viral infection may lead to formation of autoantibodies.2. Antibodies precede disease.3. However, presence of antibody does not necessarily mean disease.
GeneticFactors
(including sex)(HLA-DR)
GeneticFactors
(including sex)(HLA-DR)
GeneticFactors
(including sex)(HLA-DR)
GeneticFactors
(including sex)(HLA-DR)
Auto-antibodies
AcquiredImmune system
(HLA-DR)T/B-cells
DiseaseManifestations
Time period of years
InnateImmune system
(Toll receptor)
GeneticFactors
(including sex)(HLA-DR)
EnvironmentalFactor
(virus-such as EBV)(apoptotic fragment)
Type I IFNImmunecomplex
Ref. 32-33
The main cytokine targets match those identified in genome wide screens
• HLA-DR (T-cell), CTLA and IFN-• NF-K /IkB
• Homing receptor (CXCR5)
• Type I IFN –IRF5, STAT4, TLR3/7/9 and pkR (cytoplasmic sensor)
• B-cell activation –BLK, BAFF, IL12, and A20 (TNFAIP3)
Previously Studied in SS
• Anti-CD20 –glandular and extraglandular
• Anti-CD22-epratazumab
• BAFF (Blys)-ACR 2012 abstracts*
• Abatacept (CD40 L)-ACR 2012*
• Allogeneic mesenchymal cells-ACR 2012 abstracts and article in Blood
• www.rheumatology.org/wren/acrsearch.asp?zoom_query=acr%20abstracts%202012&st=nocache&actn=search&dt=12/24/2012%202:29:59%20P
Limited Success with antibodies to type I IFN in SS
• In animal and early clinical trials, little benefit after the disease is established—although may help delay onset.
• Novel new target IRF8 and SLAC4A, molecules that links TLR and IFN-type 1, appear more promising
Other Inhibitors of IFN
a. Initial trials of anti-type 1 IFN had infusion reactions and only modest efficacy.
b. Medi 546 (type 1 IFN-R antagonists) now in phase 1 (scleroderma) and juvenile SLE phase 2 trial.
Now we have methylation maps
These methylation maps show different targets
Summary
Sjogren’s syndrome represents the interface of:
a) Immune and exocrine secretory functions (dryness)
b) Immune and neural function (neuropathy/cognitive)
c) Immune and hypothalamic-adrenal axis (endocrine)
d) Autoimmune proliferation and lymphoma
e) Lupus-like features of vasculitis and immune complex
Thank You
It is an honor to visit with you today
The slides are available on my website
RobertFoxMD.com