Abstract
Keywords
Adipose-derived mesenchymal stem cell Fibroblast growth factor 1 Transfection Neuropathic pain
Introduction
Nerve injury-induced chronic pain was commonly referred to as neuropathic pain. Despite the rapid development of neuroscience associated with drug discovery, due to a lack of precise knowledge of neuropathic pain mechanisms, effective drugs to alleviate neuropathy symptoms are still lacking (1). Evidence suggests that neuropathic pain’s underlying pathophysiology is related to apoptosis and inflammation pathways and involves interactions between neurons, inflammatory immune, and glial cells (2, 3). Cell transplantation is a vibrant research area in the treatment of neuropathic pain (4, 5). Adipose-derived mesenchymal stem cells (AD-MSCs) influence relevant immune modulation and produce an array of neurotrophins and cytokines that positively impact cell viability. Newer studies demonstrated that the combination of growth factors (by genetic manipulation) enhances MSCs’ therapeutic potential (6-9). FGF1 (fibroblast growth factor 1) displays neuroprotective effects (8, 10). It contributes to many physiological processes, such as angiogenesis, neurogenesis, wound healing, and memory functions (10). In the previous study, we transfected AD-MSCs with FGF1 and demonstrated that our ADMSCFGF1 could secret FGF1 with proliferative and angiogenic properties (11). ADMSCsFGF1 transplantation resulted in a significant decrease in mechanical and thermal hypersensitivity in a rat model of chronic constriction injury (CCI).
Moreover, spinal structural alterations and apoptosis were decreased following AD-MSCs FGF1 administration in CCI rats (12). In light of the benefits found with our previous study, we conducted further examinations on the underlying pathways by which AD-MSCsFGF1 exert their actions on neuropathic pain. In the present study, we plan to examine some inflammatory and apoptosis markers’ expressions following administration of AD-MSCs and AD-MSCsFGF1 in the spinal cord of the rats submitted to CCI.
Experimental
Tris-HCl, ethylene diamine tetraacetic acid (EDTA), β-glycerol phosphate, bromophenol blue, sodium fluoride (NaF), glycerol, tris-buffered saline with tween 20 (TBST), sodium orthovanadate (Na3VO4), sodium deoxycholate, complete protease inhibitor cocktail (P8340), phenylmethylsulfonyl fluoride (PMSF), sodium dodecyl sulfate (SDS,) and 2-mercaptoethanol (2-ME) were bought from Sigma-Aldrich (St. Louis, MO).
Rabbit polyclonal anti-Bax, rabbit polyclonal anti-Bcl2, anti-cleaved caspase 3, and rabbit polyclonal anti-β-actin antibodies, rabbit horseradish peroxidase-conjugate anti-rabbit IgG or anti-mouse were bought from Cell Signaling Technology (Danvers, MA). Rabbit anti- IL-1β, rabbit anti-MMP2, and mouse monoclonal anti-Iba-1 were purchased from Abcam Technology (Cambridge, UK). High glucose Dulbecco’s modified Eagles medium (DMEM, 4.5 g/L), penicillin and streptomycin, and fetal calf serum (FCS) were bought from Gibco (Carlsbad, CA). Ketamine and xylazine were bought from Alfasan Co (Woerden, Holland).
Animals
Adult male Wistar rats weighing 220-270 g were obtained from the Animal Facility of the Faculty of Medicine, Mashhad University of Medical Sciences, Iran. The animals were kept in a 12 h light-dark cycle environment. Tap water and standard food pellets were available ad libitum. All Experiments were done following the National Institutes of Health Guidance for the Care and Use of Laboratory Animals, with the approval of the Animal Ethics Committee of MUMS (#930511).
Cell cultures
AD-MSCs were established, characterized, and successfully transfected by a pCMV6-Entry vector with Myc-DDK-tagged ORF clone of Rattus norvegicus fibroblast growth factor 1 (rat FGF1), as described previously (11, 13). The AD-MSCs were cultured in DMEM with 10% FBS and 1% antibiotics in a humidified atmosphere of 5% CO2, 95% air, 37 °C.
CCI surgery of sciatic nerve
Briefly, the rats were anesthetized with a cocktail containing ketamine (64 mg/kg) and xylazine (1.6 mg/kg). The neuropathic pain was induced by performing a chronic constriction injury model on the left sciatic nerve of animals, according to a method previously described by Bennet and Xie (14). The skin of the left thigh’s lateral surface was incised, the sciatic nerve was exposed, and four ligatures of 4-0-gauge chromic catgut were loosely tied around the nerve until a slight twitching was seen in the ipsilateral hind paw. The muscular and skin layer was sutured immediately with silk thread, and the animals were kept in a warm condition until complete recovery. All the surgeries were done by one person.
Study protocol
Cell administration was done intravenously on the day of nerve injury, once-daily that continued for two consecutive days. The number of cells and their concentration were 1 × 106 cells/200 µL PBS, chosen according to Forouzanfar et al.(12).
Grouping
The rats were randomly divided into four groups: Sham-operated rats (which were subjected to surgical procedure without the ligation of the sciatic nerve), CCI rats, CCI + AD-MSCs (CCI rats undergoing the intravenous delivery of AD-MSCs), and CCI + AD-MSCs FGF1 (CCI rats undergoing the intravenous delivery of AD-MSCs FGF1). Sham and CCI-operated rats were intravenously injected with the same amount of PBS alone at the same designated time points.
Western blot assay
The rats were decapitated on days 3, and 14 (n = 6 for each day) and L4-L6 region of spinal cord tissues were rapidly isolated and homogenized in the lysis buffer (10 mM 𝛽-glycerophosphate, 0.2% w/v sodium deoxycholate, 1 mM PMSF, 2 mM EGTA, 50 mM Tris-HCl (pH 7.4), 10 mM NaF, 1 mM sodium orthovanadate (Na3VO4), 2 mM EDTA, and complete protease inhibitor cocktail). The homogenates were then centrifuged at 10,000 g for 10 min at four ℃. The protein concentrations were assessed by the Bradford assay kit (15). After that, the samples with adjusted protein content were mixed 1:1 with 2 × SDS blue buffer, boiled, aliquoted, and kept at -80 °C. One hundred microgram of each protein extract was separated on 12% sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) by electrophoresis and transferred onto PVDF transfer membranes. After transferring, the blots were blocked with 5% skim milk in TBST (20 mM Tris-HCl pH 7.6, 137 mM NaCl, and 0.05% Tween-20) at 4 °C overnight. Then the blots were incubated with primary rabbit anti- IL-1β, rabbit anti-MMP2, mouse monoclonal anti-Iba-1, rabbit polyclonal anti-Bax, rabbit polyclonal anti-Bcl2, rabbit anti-cleaved caspase 3, and rabbit polyclonal anti-β-actin antibodies with an incubation time of about 1-2 h at room temperature. After washing in TBST buffer, the blots were incubated by rabbit horseradish peroxidase-conjugated anti-rabbit IgG or anti-mouse IgG secondary antibody one h at 37 °C. Enhanced chemiluminescence (Pierce, USA) was used to visualize the peroxidase-coated bands and visualized using Alliance 4.7 Gel Doc (UK). Densitometric analysis for specific protein bands was done using NIHe Image J software. The protein levels of each band were normalized against the corresponding B-actin band (12).
Statistical analysis
All behavioral data are expressed as mean ± SEM (standard error of the mean) and analyzed by one-way ANOVA, followed by Tukey-Kramer post-hoc test for multiple comparisons. The values of p < 0.05 were considered significant.
Results
AD-MSC and AD-MSCsFGF1 decreased cleaved Caspase-3 and Bax/Bcl-2 expressions in CCI rats’ spinal cord on day 3.
As indicated in (Figures 1A-C), CCI led to a substantial increase in the expression of cleaved Caspase-3 (1.9-fold) and Bax/Bcl-2 ratio (1.7-fold), as compared with the sham group (p < 0.001). On the contrary, AD-MSCs and AD-MSCsFGF1 were able to diminish the Caspase-3 expression to 1.6 (p < 0.05) and 1.1 (p < 0.001) fold in CCI rats, respectively. This corrective effect was more significant in the CCI + AD-MSCsFGF1 group (p < 0.01 compared to the CCI + AD-MSCs group).
Also, AD-MSCs and AD-MSCsFGF1 administration resulted in a decrement of Bax/Bcl-2 expression to 1.4 (p < 0.05) and 1 (p < 0.001) fold in CCI rats, respectively. The CCI + AD-MSCsFGF1 group exhibited a significantly lower expression than the CCI + AD-MSCs group (P < 0.05).
AD-MSC and AD-MSCsFGF1 decreased IL-1β expression in the spinal cord of CCI rats on day 14
As shown in (Figure 2), there was a significantly higher relative density of IL-1β expression in CCI rats (1.5 fold of control), in comparison to the sham-operated animals (p < 0.001). On the other hand, AD-MSCs and AD-MSCsFGF1 were able to decrease the IL-1β expression to 1.3 (p < 0.05) and 1.1 (p < 0.001) fold in CCI rats, respectively. Furthermore, the effect was more significant in the CCI + AD-MSCsFGF1 group (p < 0.05 compared to the CCI + AD-MSCs group).
AD-MSC and AD-MSCFGF1 decreased Iba-1 expression in the spinal cord of CCI rats on day 14.
As illustrated in (Figure 3), Iba-1 expression was increased in CCI rats (1.6 fold) as compared with the sham-operated animals (p < 0.001). On the contrary, AD-MSCs and AD-MSCsFGF1 administration resulted in a decrement of Iba-1 expression to 1.4 (p < 0.05) and 1.2 (p < 0.001) fold in CCI rats, respectively. The CCI + AD-MSCsFGF1 group showed a significantly lower expression than the CCI + AD-MSCs group (p < 0.05).
AD-MSC and AD-MSCsFGF1 decreased MMP-2 expression in the spinal cord of CCI rats on day 14.
As shown in (Figure 4), western blot analysis in the CCI group revealed a significant increase in the MMP-2 expression (1.7 fold) in comparison to the sham-operated animals (p < 0.001). On the other hand, AD-MSCs and AD-MSCsFGF1 were able to decrease the MMP-2 expression to 1.4 (p < 0.01) and 1.2 (p < 0.001) fold in CCI rats, respectively. The effect was more significant in the CCI + AD-MSCsFGF1 group (p < 0.05 compared to the CCI + AD-MSCs group).
Discussion
In the present study, we demonstrated that the intravenous administration of AD-MSCs FGF1 effectively diminishes apoptosis and inflammation of neuropathic pain that originates from a peripheral lesion. Following the peripheral nerve injury, a cascade of neuroinflammation-related events occurs in pain generation (3, 16). Microglia are one of the first spinal cord cell types activated within the first hours of peripheral nerve injury, which continues for at least numerous months in experimental neuropathies. Microglial activation is characterized by the expression of Iba1 (3). The release of IL-1β from spinal cells was enhanced following the responses to pathophysiological changes during neuropathic pain (17). More pertinently in spinal cord neurons, IL-1β enhanced excitatory AMPA and NMDA-induced currents whilst suppressed GABA- and glycine-induced inhibitory currents (18). Previous studies suggested that IL-1β induction of NMDA-currents may be via PK-C that phosphorylates NMDA subunits, NR1 and NR2B (19). The inhibition of IL-1β signaling prevented transcriptional up-regulation of the COX-2 gene, which resulted in the reduction of mechanical hyperalgesia and normalization of pain sensitivity (20). Matrix metalloproteinases (MMPs) are zinc-dependent proteins, have imperative roles in numerous proteolytic reactions, and are associated with different neurodegenerative disorders (21). They degrade structural proteins of the extracellular and increase the amount of pro-inflammatory cytokines such as IL-1β (22). In the context of neuropathic pain, elevated MMP-2 contributes to the development of neuropathic pain (23). In accordance with previous literature (21, 24), Iba1, IL-1β, and MMP-2 upregulation were seen on day 14 post-CCI. Administration of AD-MSCs and AD-MSCs FGF1 significantly attenuated the contents of Iba1, IL-1β, and MMP-2, in the spinal cord of animals subjected to nerve injury. The corrective effect was greater in the AD-MSCs FGF1 group. AD-MSCs are known to provide anti-inflammatory and anti-apoptotic by producing many growth factors, cytokines, and chemokines (25). In a study by Sacerdote’s et al., AD-MSc administration reduced the pro-inflammatory cytokine IL-1β. It increased the anti-inflammatory cytokine IL-10 in the injured nerve of the CCI rats. Besides, AD-MSc administration decreased the expression of inducible nitric oxide synthase in CCI animals’ spinal cord (26). In a study conducted by Siniscalco et al., injection of human MSCs to neuropathic mice led to decreased NP-like behaviors, mRNA levels of the pro-inflammatory interleukin IL-1β mouse gene, as well as astrocytic and microglial cell activations (27). FGF1 induced the expression of T helper type 2 (Th2) cytokine IL-4 and sequential upregulation of arginase-I (Arg I) (28). Arg I enhances the synthesis of polyamines that promote axonal regeneration and prevent cell death after injury (29). Subsequently, the upregulation of Arg I leads to a decrement of the inflammatory response and neuropathic pain occurrence (30). In a study conducted by Lin et al., following cervical root transection, intercostal nerve grafts and FGF1 resulted in a decrement of microglial and IL-1β-positive astrocyte reactions in the spinal cord, along with a significant increase in arginase I expression (30). The apoptotic processes appear and develop during the first few days after the induction of CCI. Subsequently, increased expression of anti-apoptotic Bcl-2 family genes may inhibit more neuronal loss. It could be associated with the own neuroprotection mechanisms of the nervous system (31, 32). The results presented here show a significant elevation in the Bax/Bcl2 ratio and cleaved caspases 3 in CCI animals on day three post-surgery. Treatment with AD-MSCs and AD-MSCs FGF1 leads to correction of the expressions of these factors. Again, the corrective effect was greater in the AD-MSCs FGF1 group. Previously, we also showed that FGF1 therapy, along with stem cell transplantation, markedly diminished the CCI-induced DNA fragmentation and apoptosis in the spinal cord of CCI rats (12). FGF1 is a differentiation and survival factor with multiple biological effects, such as angiogenesis, mitogenesis, and repair. It is highly expressed in the central and peripheral nervous systems (33, 34). FGF1 is a repressed target gene of p53. The overexpression of FGF1 via increasing MDM2 (mouse double minute 2) expression leads to a decrement of pro-apoptotic and the anti-proliferative effects of p53 and Bax, a pro-apoptotic protein (35). In the presence of DNA damages, FGF1 leads to a decrement in p53 stability activities and p53-dependent transactivation of the pro-apoptotic genes, such as puma, noxa, and caspases 3 (34). In conclusion, the present study demonstrated that intravenous administration of AD-MSCs, transfected with the FGF1 gene, resulted in significant improvements in the spinal cord’s apoptosis and inflammation in a rat model of CCI, with greater efficacy than non-modified AD-MSCs and has vast potential for future studies.
Acknowledgements
References
-
1.
Rice AS, Smith BH, Blyth FM. Pain and the global burden of disease. Pain. 2016;157:791-6. [PubMed ID: 26670465].
-
2.
Zhang JM, An J. Cytokines, inflammation and pain. Int. Anesthesiol. Clin. 2007;45:27-37. [PubMed ID: 17426506].
-
3.
Austin PJ, Moalem Taylor G. The neuro-immune balance in neuropathic pain: involvement of inflammatory immune cells, immune-like glial cells and cytokines. J. Neuroimmunol. 2010;229:26-50. [PubMed ID: 20870295].
-
4.
Gutiérrez Fernández M, Rodríguez Frutos B, Otero Ortega L, Ramos Cejudo J, Fuentes B, Díez-Tejedor E. Adipose tissue-derived stem cells in stroke treatment: from bench to bedside. Discov. Med. 2013;16:37-43. [PubMed ID: 23911230].
-
5.
Haico de Gast M, Torrensma B, Fitzgerald E, Stevens H. The Treatment of Chronic Neuropathic Pain: Bio (Regenerative) Pain Treatment through Lipofilling A Short Communication Case Series. Pain Physician. 2016;19:E495-E8. [PubMed ID: 27008307].
-
6.
Kroon E, Martinson LA, Kadoya K, Bang AG, Kelly OG, Eliazer S, Young H, Richardson M, Smart NG, Cunningham J. Pancreatic endoderm derived from human embryonic stem cells generates glucose-responsive insulin-secreting cells in-vivo. Nat. Biotechnol. 2008;26:443-52. [PubMed ID: 18288110].
-
7.
Li X, Gan K, Song G, Wang C. VEGF gene transfected umbilical cord mesenchymal stem cells transplantation improve the lower limb vascular lesions of diabetic rats. J. Diabetes Complications. 2015;29:872-81. [PubMed ID: 26077346].
-
8.
Ghazavi H, Hoseini SJ, Ebrahimzadeh-Bideskan A, Mashkani B, Mehri S, Ghorbani A, Sadri K, Mahdipour E, Ghasemi F, Forouzanfar F, Hoseini A, Pasdar AR, Sadeghnia HR, Ghayour- Mobarhan M. Fibroblast Growth Factor Type 1 (FGF1)-Overexpressed Adipose-Derived Mesenchaymal Stem Cells (AD-MSCFGF1) Induce Neuroprotection and Functional Recovery in a Rat Stroke Model. Stem. Cell Rev. Rep. 2017;13:670-85. [PubMed ID: 28795363].
-
9.
Lee HY, Lee HL, Yun Y, Kim JS, Ha Y, Yoon DH, Lee SH, Shin DA. Human adipose stem cells improve mechanical allodynia and enhance functional recovery in a rat model of neuropathic pain. Tissue Eng. Part A. 2015;21:2044-52. [PubMed ID: 25857679].
-
10.
Raju R, Palapetta SM, Sandhya VK, Sahu A, Alipoor A, Balakrishnan L, Advani J, George B, Kini KR, Geetha N. A network map of FGF-1/FGFR signaling system. J. Sig. Transd. 2014;2014:962962.
-
11.
Hoseini SJ, Ghazavi H, Forouzanfar F, Mahkani B, Ghorbani A, Mahdipour E, Ghasemi F, Sadeghnia HR, Ghayour Mobarhan M. Fibroblast Growth Factor 1-Transfected Adipose-Derived Mesenchymal Stem Cells Promote Angiogenic Proliferation. DNA. Cell Biol. 2017;36:401-12. [PubMed ID: 28281780].
-
12.
Forouzanfar F, Amin B, Ghorbani A, Ghazavi H, Ghasemi F, Sadri K, Mehri S, Sadeghnia HR, Hosseinzadeh H. New approach for the treatment of neuropathic pain: Fibroblast growth factor 1 gene-transfected adipose-derived mesenchymal stem cells. Eur. J. Pain. 2017;22:295-310. [PubMed ID: 28949091].
-
13.
Ghorbani A, Jalali SA, Varedi M. Isolation of adipose tissue mesenchymal stem cells without tissue destruction: a non-enzymatic method. Tissue Cell. 2014;46:54-8. [PubMed ID: 24321269].
-
14.
Bennett GJ, Xie YK. A peripheral mononeuropathy in rat that produces disorders of pain sensation like those seen in man. Pain. 1988;33:87-107. [PubMed ID: 2837713].
-
15.
Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem. 1976;72:248-54. [PubMed ID: 942051].
-
16.
Martucci C, Trovato AE, Costa B, Borsani E, Franchi S, Magnaghi V, Panerai AE, Rodella LF, Valsecchi AE, Sacerdote P. The purinergic antagonist PPADS reduces pain related behaviours and interleukin-1β, interleukin-6, iNOS and nNOS overproduction in central and peripheral nervous system after peripheral neuropathy in mice. Pain. 2008;137:81-95. [PubMed ID: 17900807].
-
17.
Liu T, Jiang CY, Fujita T, Luo SW, Kumamoto E. Enhancement by interleukin-1β of AMPA and NMDA receptor-mediated currents in adult rat spinal superficial dorsal horn neurons. Mol. pain. 2013;16:9-16.
-
18.
Kawasaki Y, Zhang L, Cheng JK, Ji RR. Cytokine mechanisms of central sensitization: distinct and overlapping role of interleukin-1β, interleukin-6, and tumor necrosis factor-α in regulating synaptic and neuronal activity in the superficial spinal cord. J. Neurosci. 2008;28:5189-94. [PubMed ID: 18480275].
-
19.
Brenner GJ, Ji RR, Shaffer S, Woolf CJ. Peripheral noxious stimulation induces phosphorylation of the NMDA receptor NR1 subunit at the PKC-dependent site, serine-896, in spinal cord dorsal horn neurons. Eur. J. Neurosci. 2004;20:375-84. [PubMed ID: 15233747].
-
20.
Samad TA, Moore KA, Sapirstein A, Billet S. Interleukin-1beta-mediated induction of Cox-2 in the CNS contributes to inflammatory pain hypersensitivity. Nature. 2001;410:471-5. [PubMed ID: 11260714].
-
21.
Pizzi MA, Crowe MJ. Matrix metalloproteinases and proteoglycans in axonal regeneration. Exp. Neurol. 2007;204:496-511. [PubMed ID: 17254568].
-
22.
Lakhan SE, Avramut M. Matrix metalloproteinases in neuropathic pain and migraine: friends, enemies, and therapeutic targets. Pain Res. Treat. 2012;18:952906.
-
23.
Kawasaki Y, Xu ZZ, Wang X, Park JY, Zhuang ZY, Tan P-H, Gao YJ, Roy K, Corfas G, Lo EH. Distinct roles of matrix metalloproteases in the early-and late-phase development of neuropathic pain. Nat. Med. 2008;14:331-6. [PubMed ID: 18264108].
-
24.
Rahbardar MG, Amin B, Mehri S, Mirnajafi-Zadeh SJ, Hosseinzadeh H. Anti-inflammatory effects of ethanolic extract of Rosmarinus officinalis and rosmarini acid in a rat model of neuropathic pain. Biomed. Pharmacother. 2017;86:441-9. [PubMed ID: 28012923].
-
25.
Kocan B, Maziarz A, Tabarkiewicz J, Ochiya T, Banaś Ząbczyk A. Trophic Activity and Phenotype of Adipose Tissue-Derived Mesenchymal Stem Cells as a Background of Their Regenerative Potential. Stem. Cells Int. 2017;12:1-13.
-
26.
Sacerdote P, Niada S, Franchi S, Arrigoni E, Rossi A, Yenagi V, De Girolamo L, Panerai AE, Brini AT. Systemic administration of human adipose-derived stem cells reverts nociceptive hypersensitivity in an experimental model of neuropathy. Stem Cells Dev. 2012;22:1252-63.
-
27.
Siniscalco D, Giordano C, Galderisi U, Luongo L, de Novellis V, Rossi F, Maione S. Long-lasting effects of human mesenchymal stem cell systemic administration on pain-like behaviors, cellular, and biomolecular modifications in neuropathic mice. Front. Integr. Neurosci. 2011;5:79. [PubMed ID: 22164136].
-
28.
Kuo HS, Tsai MJ, Huang MC, Chiu CW, Tsai CY, Lee MJ, Huang WC, Lin YL, Kuo WC, Cheng H. Acid fibroblast growth factor and peripheral nerve grafts regulate Th2 cytokine expression, macrophage activation, polyamine synthesis, and neurotrophin expression in transected rat spinal cords. J. Neurosci. 2011;31:4137-47. [PubMed ID: 21411654].
-
29.
Cai D, Deng K, Mellado W, Lee J, Ratan RR, Filbin MT. Arginase I and polyamines act downstream from cyclic AMP in overcoming inhibition of axonal growth MAG and myelin in-vitro. Neuron. 2002;35:711-9. [PubMed ID: 12194870].
-
30.
Lin YL, Kuo HS, Lo MJ, Tsai MJ, Lee MJ, Huang WC, Kuo WC, Shih YH, Cheng H, Huang M-C. Treatment with nerve grafts and aFGF attenuates allodynia caused by cervical root transection injuries. Restor. Neurol. Neurosci. 2011;29:265-74. [PubMed ID: 21697592].
-
31.
Siniscalco D, Giordano C, Fuccio C, Luongo L, Ferraraccio F, Rossi F, de Novellis V, Roth KA, Maione S. Involvement of subtype 1 metabotropic glutamate receptors in apoptosis and caspase-7 over-expression in spinal cord of neuropathic rats. Pharmacol. Res. 2008;57:223-33. [PubMed ID: 18325779].
-
32.
de Novellis V, Siniscalco D, Galderisi U, Fuccio C, Nolano M, Santoro L, Cascino A, Roth KA, Rossi F, Maione S. Blockade of glutamate mGlu5 receptors in a rat model of neuropathic pain prevents early over-expression of pro-apoptotic genes and morphological changes in dorsal horn lamina II. Neuropharmacology. 2004;46:468-79. [PubMed ID: 14975670].
-
33.
Delmas E, Jah N, Pirou C, Bouleau S, Le Floch N, Vayssière J, Mignotte B, Renaud F. FGF1 C-terminal domain and phosphorylation regulate intracrine FGF1 signaling for its neurotrophic and anti-apoptotic activities. Cell Death Dis. 2016;7:e2079. [PubMed ID: 26844696].
-
34.
Rodriguez Enfedaque A, Bouleau S, Laurent M, Courtois Y, Mignotte B, Vayssière JL, Renaud F. FGF1 nuclear translocation is required for both its neurotrophic activity and its p53-dependent apoptosis protection. Biochim. Biophys. Acta. 2009;1793:1719-27. [PubMed ID: 19765618].
-
35.
Bouleau S, Grimal H, Rincheval V, Godefroy N, Mignotte B, Vayssiere JL, Renaud F. FGF1 inhibits p53-dependent apoptosis and cell cycle arrest via an intracrine pathway. Oncogene. 2005;24:7839-49. [PubMed ID: 16091747].