Background & Aims
Fabry disease (FD) is an X-linked lysosomal storage disorder characterized by a deficient alpha-galactosidase A (Gal-A) which leads to Gb3 accumulation in different tissues, including the nervous system. More than 80% of FD patients suffer from lifetime-lasting neuropathic pain that develops in childhood and is resistant to specific treatments. Glial and infiltrating immune cells are involved in neuropathic pain pathogenesis as well as the prokineticin system (PKS), a family of chemokines composed of PK2 and its receptors, whose antagonism can contrast chronic inflammatory/neuropathic pain, contrasting neuroinflammation. Considering this evidence both glia and PKS may represent a new therapeutic target for FD pain.
With this preclinical study, we want to counteract FD neuropathic pain, with a focus on neuroinflammation, testing and validating PKS antagonism with PC1 as a novel pharmacological strategy and proposing a drug repurposing strategy through glial inhibition with minocycline
Methods
10-weeks male mice, genetically modified in order to delete alpha-galactosidase gene (KO GLA), were used as an FD experimental model and their painful symptoms were characterized by the Plantar Test (thermal hyperalgesia), Von Frey Test (mechanical allodynia), Von Frey Filament Test (referred abdominal pain) and Cold Plate Test (hypo/hypersensitivity to cold stimuli). Then, FD mice were treated with PC1 (150 µg/kg, subcutaneous, twice a day) or with minocycline (10 mg/kg, intraperitoneal, once a day) for fourteen consecutive days and the behavioral tests mentioned above were constantly repeated to monitor the chronic treatment effects. The levels of PK2, PK receptors, (neuro)inflammatory markers like cytokines, immune cells and glial markers and neuronal damage markers were evaluated in the sciatic nerve, dorsal root ganglia (DRG), spinal cord and gut as mRNA (rtPCR) and protein (Western Blot and IHC).
Results
Our results showed that FD mice were characterized by extensive thermal hyperalgesia, mechanical allodynia and referred abdominal pain, but they were only slightly hyposensitive to cold. Biochemical analyses revealed that all these behavioral alterations were related to a marked neuroinflammatory state. Indeed, FD animals showed evident neuroinflammation with a clear up-regulation of PKS levels and an increase in pro-inflammatory cytokines expression, accompanied by an over-activation of immune/glial cells and by an over-expression of neuronal marker in the nerve and DRG, while in the spinal cord we found just an up-regulation of the pro-inflammatory cytokines. FD mice also presented an inflammation in the gut, highlighted by PK2 and pro-inflammatory cytokines over-expression. Treatments with both PC1 and minocycline contrasted all the painful symptoms, reducing neuroinflammation.
Conclusions
Our data underline that the PK system and non-neuronal cells present in the peripheral nervous system are certainly involved in the development of neuroinflammation and neuropathic pain in Fabry disease. Furthermore, the results show how pharmacological treatments that can contrast the prokineticin system over-expression, glial activation, and pro-inflammatory cytokine production have clearly analgesic effects, even with different mechanisms. So, in conclusion, these data are promising if we consider that, to date, no side effects related to PK system antagonists have been highlighted. In addition, our data acquire further value if we think about a drug repurposing approach for minocycline, an antibiotic already used in clinics also for pain, but not prescribed for the painful symptoms of Fabry disease.
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Presenting Author
Giulia Galimberti
Poster Authors
Giulia Galimberti
MD
University of Milan
Lead Author
Silvia Franchi
University of Milan
Lead Author
Giada Amodeo
University of Milan
Lead Author
Giulia Magni
PhD
University of Milan
Lead Author
Benedetta Riboldi
Università degli Studi di Milano
Lead Author
Stefania Ceruti
PhD
University of Milan
Lead Author
paola sacerdote
Universita degli Studi di Milano
Lead Author
Topics
- Models: Chronic Pain - Neuropathic