Nogo-a Pathway Contributes to Neural Injury and Pain in Sickle Cell Disease

Sickle cell disease (SCD) is characterized by chronic pain and bouts of extreme acute pain from vasoocclusive crises (VOC). Sickle pain has both neuropathic and inflammatory features (Tran et al., Blood 2017). Mechanisms underlying neural injury remain unknown in SCD. Neurite outgrowth inhibitor (NOGO-A/reticulon-4) and its receptor NGR1 contribute to pain, neuronal damage, and inhibition of neurite outgrowth (Hu et al., FASEB J 2019). We examined if NOGO-A pathway is activated in a sickle microenvironment and if its inhibition will ameliorate hyperalgesia in BERK sickle mice. We used Rho kinase activity (ROCK) downstream of NGR1 as a readout of activation of NOGO-A/NGR1 pathway. We observed increased expression of NOGO-A (~260%, p<0.05) and NGR1 (~180%, p<0.05) in the dorsal root ganglia, and increased NOGO-A and ROCK activity in spinal cords of sickle mice compared to control mice expressing normal human hemoglobin A. Earlier, we found that an endogenous cannabinoid, palmitoylethanolamide (PEA) inhibits spinal NOGO-A expression and ROCK activity in sickle mice (Argueta et al., ASH 2020 #225). We hypothesized that sickle microenvironment with cell-free heme and inflammation activates NOGO-A/NGR1-ROCK pathway leading to nerve injury and pain, and inhibition of this pathway will ameliorate hyperalgesia in sickle mice. Using terminally differentiated rat pheochromocytoma (PC12) cells, we simulated a sickle microenvironment with hemin (40 µM) and TNFα (1 ng/ml) (H+T). H+T elevated ROCK activity compared to vehicle (~40%, p<0.05). PEA (30 uM) and 2 µM NEP (1-40), a competitive antagonist of NGR1, attenuated H+T-induced ROCK activity (both p<0.01); co-treatment had no additive effect, indicating a common pathway. As well, siRNA (10 nM) knockdown of NGR1 reversed H+T-induced ROCK activity (p<0.001), which was equally effective with 30 µM PEA co-treatment. Functionally, treatment with 30 µM PEA or 2 µM NEP (1-40) enhanced neurite outgrowth in H+T-treated PC-12 cells (~120%, p<0.001). NEP (1-40) at 5 mg/kg reduced mechanical and cold (both ~50%, p<0.001) hyperalgesia in sickle mice compared to baseline (BL) and/or vehicle treatment. Together, these data demonstrate that NOGO-A/NGR1 pathway activation may underlie nerve injury, and inhibition of this pathway with a NGR1 antagonist or PEA promotes neurite outgrowth and reduces hyperalgesia in a sickle microenvironment. We next examined the contribution of exogenously administered and endogenously produced PEA in ameliorating hyperalgesia. Mass spectrometry revealed that spinal PEA is reduced in female (p<0.05) and male (p<0.001) sickle mice compared to age/sex-matched control mice. Exogenous PEA (i.p. 20 mg/kg/d) reduced cold avoidance over a 3-day treatment period, showing significantly more time in the cold chamber compared to BL or vehicle at 1 h, 24 h, and 72 h (p<0.05). The analgesic effect of PEA was maintained for 9 days of treatment without developing tolerance. We next increased endogenous PEA by inhibiting its degradative enzyme, N-acylethanolamine acid amidase, with ARN19702 (i.p. 3, 10, & 30 mg/kg/d), which reduced mechanical (~50%, p<0.001) and cold hyperalgesia (~40%, p<0.001) over 72 hours in a dose-dependent manner. Since hypoxia and ischemia reperfusion injury contribute to acute VOC pain, we incited hypoxia-reoxygenation (HR; 3 h @ 8% O 2, 92% N 2, followed by 1 h @ normoxia) to simulate acute VOC pain. We observed that 5-day pretreatment with PEA (i.p. 20 mg/kg/d) before HR prevented mechanical and cold hyperalgesia following HR in sickle mice. Moreover, treatment with PEA after HR incitement significantly reduced hyperalgesia for 24 h after HR compared to BL (~30%, p<0.001) and vehicle treated (~66%, p<0.001) sickle mice. NGR1 antagonism reduces spinal microglial injury/activation. Heme and TNFα have been shown to cause microglial injury in vitro, while spinal microglial activation has been demonstrated in sickle mice (Lei et al., Antioxid Redox Signal 2021). Thus, NGR1/ROCK cascade may contribute to both neuronal injury and inflammation in the central nervous system leading to neuropathic pain. Our data suggest that PEA and targeting NOGO-A pathway may prevent/reduce chronic and acute hyperalgesia in sickle mice. We speculate that interventions targeting NOGO-A pathway may prevent/reduce neuropathic pain and that PEA has the translational potential for the treatment of chronic and acute pain in SCD. Disclosures Gupta: Tautona Group: Consultancy, Honoraria; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; 1910 Genetics: Other: Grantee; Grifols: Other: Grantee; SCDAA: Membership on an entity's Board of Directors or advisory committees; CSL Behring LLC: Honoraria; NIH: Other: Grantee; University of Minnestoa Foundation: Other: Philanthropic Funding; Southern California Institute for Research and Education Foundation: Other: Philanthropic Funding; Cyclerion: Research Funding; UCI Foundation: Other: Philanthropic Funding.

Hydrochlorothiazide Reduces Cardiac Hypertrophy, Fibrosis and Rho-Kinase Activation in DOCA-Salt Induced Hypertension

Background: Thiazides are one of the most common antihypertensive drugs used for hypertension treatment and hydrochlorothiazide (HCTZ) is the most frequently used diuretic for hypertension treatment. The Rho/Rho-kinase (ROCK) path plays a key function in cardiovascular remodeling. We hypothesized that in preclinical hypertension HCTZ reduces myocardial ROCK activation and consequent myocardial remodeling. Methods: The preclinical model of deoxycorticosterone (DOCA)-salt hypertension was used (Sprague–Dawley male rats). After 3 weeks, in 3 different groups: HCTZ, the ROCK inhibitor fasudil or spironolactone was added (3 weeks). After 6 weeks myocardial hypertrophy and fibrosis, cardiac levels of profibrotic proteins, mRNA levels (RT PCR) of pro remodeling and pro oxidative molecules and ROCK activity were determined. Results: Blood pressure, myocardial hypertrophy and fibrosis were reduced significantly by HCTZ, fasudil and spironolactone. In the heart, increased levels of the pro-fibrotic proteins Col-I, Col-III and TGF-β1 and gene expression of pro-remodeling molecules TGF-β1, CTGF, MCP-1 and PAI-1 and the pro-oxidative molecules gp91phox and p22phox were significantly reduced by HCTZ, fasudil and spironolactone. ROCK activity in the myocardium was increased by 54% ( P < 0.05) as related to the sham group and HCTZ, spironolactone and fasudil, reduced ROCK activation to control levels. Conclusions: HCTZ reduced pathologic LVH by controlling blood pressure, hypertrophy and myocardial fibrosis and by decreasing myocardial ROCK activation, expression of pro remodeling, pro fibrotic and pro oxidative genes. In hypertension, the observed effects of HCTZ on the myocardium might explain preventive outcomes of thiazides in hypertension, specifically on LVH regression and incident heart failure.

Left Cardiac Remodelling Assessed by Echocardiography Is Associated with Rho-Kinase Activation in Long-Distance Runners

This single-blind and cross-sectional study evaluated the role of Rho-kinase (ROCK) as a biomarker of the cardiovascular remodelling process assessed by echocardiography in competitive long-distance runners (LDRs) during the training period before a marathon race. Thirty-six healthy male LDRs (37.0 ± 5.3 years; 174.0 ± 7.0 height; BMI: 23.8 ± 2.8; V˙ O2-peak: 56.5 ± 7.3 mL·kg−1·min−1) were separated into two groups according to previous training level: high-training (HT, n = 16) ≥ 100 km·week−1 and low-training (LT, n = 20) ≥ 70 and < 100 km·week−1. Also, twenty-one healthy nonactive subjects were included as a control group (CTR). A transthoracic echocardiography was performed and ROCK activity levels in circulating leukocytes were measured at rest (48 h without exercising) the week before the race. The HT group showed a higher left ventricular mass index (LVMi) and left atrial volume index (LAVi) than other groups (p < 0.05, for both); also, higher levels of ROCK activity were found in LDRs (HT = 6.17 ± 1.41 vs. CTR = 1.64 ± 0.66 (p < 0.01); vs. LT = 2.74 ± 0.84; (p < 0.05)). In LDRs a direct correlation between ROCK activity levels and LVMi (r = 0.83; p < 0.001), and LAVi (r = 0.70; p < 0.001) were found. In conclusion, in male competitive long-distance runners, the load of exercise implicated in marathon training is associated with ROCK activity levels and the left cardiac remodelling process assessed by echocardiography.

Rho Kinase Expression in Giant Cell Arteritis Validating pERM Intensity Score as a Method of Increasing Sensitivity of Temporal Artery Biopsy

Background: Aberrant rho-kinase (ROCK) activity is implicated in pathogenesis of several vascular and immunologic disorders. We previously demonstrated evidence of increased ROCK activity in histopathologically negative temporal artery biopsies (TAB) of subjects with clinical Giant Cell Arteritis (GCA) compared to those without GCA. This study aimed to examine ROCK activity in a larger cohort of biopsy-negative GCA subjects and to validate the prior findings. Methods: Subjects were categorized into 2 groups based on clinical data 6-months after TAB: biopsy-negative GCA and controls without GCA. Paraffin-embedded TAB were stained for phosphorylated ezrin/radixin/moesin (pERM), a surrogate of ROCK activity, and scored by two pathologists blinded to clinical diagnosis using a previously derived scoring system. Three areas of the vessel (intima, adventitial and vasa vasorum) were scored for staining intensity on a scale of 0–2, with a maximum possible score of 6 for each TAB. As determined a priori, scores ³4 were considered a high pERM intensity score correlating with ROCK activity. TAB sections were also stained for unphosphorylated ERM, the inactive protein. Results: Thirty six subjects with biopsy-negative GCA and 43 controls were analyzed. There were no differences between groups in age, sex and corticosteroid dose. The mean pERM intensity score in non-GCA subjects was 3.9 ± 1.4 (compared to 5.0 ± 1.4 in those with GCA, p = 0.002). Using the predetermined cut-off of 4 to define high pERM intensity, subjects with GCA were significantly more likely to have a high pERM intensity score compared to non-GCA, OR 3.67, 95%CI :1.19,11.36; p= 0.019. The sensitivity of high pERM intensity score for diagnosis of GCA in histologically negative TAB was 86%, 95%CI: 70,95. Conclusions:. In this well characterized cohort, those with GCA and negative biopsies had significantly higher pERM intensity scores in TAB specimens compared to subjects without GCA. pERM staining has diagnostic significance in enhancing the sensitivity of TAB, and helps to define the clinically important group of biopsy-negative GCA. The ROCK pathway warrants further investigation in GCA and may be a potential therapeutic target

Renal ROCK Activation and Its Pharmacological Inhibition in Patients With Diabetes

Rho-associated coiled-coil-containing protein kinase (ROCK) is a serine/threonine kinase with essential roles in cytoskeletal functions. Substantial evidence implicates ROCK as a critical regulator in the inception and progression of diabetic nephropathy through a mechanism involving mesangial fibrosis, podocyte apoptosis, and endothelial inflammation. Despite these experimental observations, human data is lacking. Here we show that the phosphorylated form of myosin phosphatase targeting subunit 1 (MYPT1), a ROCK substrate, was increased in both the glomerular and tubulointerstitial areas in patients with histologically confirmed diabetic nephropathy. We also conducted a retrospective pilot analysis of data from patients with diabetes to assess the renoprotective effects of fasudil, an ATP-competitive ROCK inhibitor licensed in Japan for the prevention of vasospasm following subarachnoid hemorrhage. Fifteen subjects (male, n = 8; female, n = 7; age 65.7 ± 14.7 years; body height, 161.1 ± 12.6 cm; body weight, 57.6 ± 13.7 kg; body mass index, 22.4 ± 3.7 kg/m2) were enrolled to evaluate blood pressure and the renal outcome after fasudil treatment. Of note, proteinuria was significantly reduced at the end of the fasudil treatment without affecting the blood pressure or estimated glomerular filtration rate. Taken together, these findings suggest that the administration of fasudil could be associated with a better renal outcome by inhibiting the ROCK activity in patients with diabetes.

Left Cardiac Remodelling assessed by Echocardiography is Associated with Rho-kinase Activation in Long-distance Runners

This single-blind and cross-sectional study evaluated the role of Rho-kinase (ROCK) as a biomarker of the cardiovascular remodelling process assessed by echocardiography in competitive long-distance runners (LDR) during the training period before a marathon race. Thirty-six healthy male LDR (37.0±5.3 years; 174.0±7.0 height; BMI: 23.8±2.8; VO2-peak: 56.5±7.3 mL·kg-1·min-1) were separated into two groups according to previous training level: high-training (HT, n=16) ≥100 km·week-1 and low-training (LT, n=20) ≥70 and &amp;lt;100 km·week-1. Also, twenty-one healthy nonactive subjects were included as a control group (CTR). A transthoracic echocardiography was performed and ROCK activity levels in circulating leukocytes were measured at rest (48-hr without exercising) the week before the race. HT group showed higher left ventricular mass index (LVMi) and left atrial volume index (LAVi) than other groups (p&amp;lt;0.05, for both), also higher levels of ROCK activity were found in LDR (HT=6.17±1.41 vs CTR=1.64±0.66 (p&amp;lt;0.01); vs LT=2.74±0.84; (p&amp;lt;0.05)). In LDR a direct correlation between ROCK activity levels and LVMi (r=0.83; p&amp;lt;0.001), and LAVi (r=0.70; p&amp;lt;0.001) were found. In conclusion, in male competitive long-distance runners, the load of exercise implicated in marathon training is associated with ROCK activity levels and the left cardiac remodelling process assessed by echocardiography.

Myosin Light Chain Kinase driven myosin II turnover regulates actin cortex contractility during mitosis

Force generation by the molecular motor myosin II (MII) at the actin cortex is a universal feature of animal cells. Despite its central role in driving cell shape changes, the mechanisms underlying MII regulation at the actin cortex remain incompletely understood. Here we show that Myosin Light Chain Kinase (MLCK) promotes MII turnover at the mitotic cortex. Inhibition of MLCK resulted in an alteration of the relative levels of phosphorylated Regulatory Light Chain (RLC), with MLCK preferentially creating a short-lived pRLC species and Rho associated kinase (ROCK) preferentially creating a stable ppRLC species during metaphase. Slower turnover of MII and altered RLC homeostasis upon MLCK inhibition correlated with increased cortex tension, driving increased membrane bleb initiation and growth, but reduced bleb retraction during mitosis. Taken together, we show that ROCK and MLCK play distinct roles at the actin cortex during mitosis; ROCK activity is required for recruitment of MII to the cortex, while MLCK activity promotes MII turnover. Our findings support the growing evidence that MII turnover is an essential dynamic process influencing the mechanical output of the actin cortex. [Media: see text]

Yap activation in irradiated parotid salivary glands is regulated by ROCK activity

Radiotherapy plays a major role in the curative treatment of head and neck cancer, either as a single modality therapy, or in combination with surgery or chemotherapy, or both. Despite advances to limit radiation-induced side-effects, the major salivary glands are often affected. This frequently leads to hyposalivation which causes an increased risk for xerostomia, dental caries, mucositis, and malnutrition culminating in a significant impact on patients’ quality of life. Previous research demonstrated that loss of salivary function is associated with a decrease in polarity regulators and an increase in nuclear Yap localization in a putative stem and progenitor cell (SPC) population. Yap activation has been shown to be essential for regeneration in intestinal injury models; however, the highest levels of nuclear Yap are observed in irradiated salivary SPCs that do not regenerate the gland. Thus, elucidating the inputs that regulate nuclear Yap localization and determining the role that Yap plays within the entire tissue following radiation damage and during regeneration is critical. In this study, we demonstrate that radiation treatment increases nuclear Yap localization in acinar cells and Yap-regulated genes in parotid salivary tissues. Conversely, administration of insulin-like growth factor 1 (IGF1), known to restore salivary function in mouse models, reduces nuclear Yap localization and Yap transcriptional targets to levels similar to untreated tissues. Activation of Rho-associated protein kinase (ROCK) using calpeptin results in increased Yap-regulated genes in primary acinar cells while inhibition of ROCK activity (Y-27632) leads to decreased Yap transcriptional targets. These results suggest that Yap activity is dependent on ROCK activity and provides new mechanistic insights into the regulation of radiation-induced hyposalivation.

Palmitoylethanolamide-Mediated Inhibition of Nogo-a Signaling Attenuates Pain in Sickle Mice

Sickle cell disease (SCD) is characterized by multiple comorbidities including pain. SCD patients often use cannabinoids to alleviate pain, but their psychoactive effects and social stigma impose major challenges. Strategies to elevate endogenous cannabinoids (eCBs) are devoid of such challenges, but pharmacologic approaches showed adverse-effects in clinical trials. Therefore, we examined the potential of non-pharmacologic integrative approaches to elevate eCBs. Enriched high-energy diet has been shown to increase levels of eCBs (Argueta et al., Front Physiol 2019) and when combined with companionship reduced hyperalgesia in sickle mice (Tran et al., Blood 2016). We hypothesized that enriched diet and companionship would enhance eCBs without adverse effects and reduce hyperalgesia by inhibiting peripheral and central pro-nociceptive mechanisms. We fed male homozygous-BERK (sickle) mice, regular Rodent Diet (RD; 2018, Harlan) or customized high calorie enriched Sickle Mouse Diet (SD; 59M3, TestDiet), housed with or without a female companion (C+ or C-, respectively) for 3-weeks. RD/SD contain 18.6/26.4% protein, 6.2/11.1% fat, 24/27.5% carbohydrates and 18/26% kcal/g, respectively; and SD contains higher minerals, vitamins and ω-3 fatty acids compared to RD. Control HbAA-BERK and sickle mice were divided into 4 groups: [i] R/C-, RD, no companion, [ii] S/C-, SD without companion, [iii] R/C+, RD with companion, and [iv] S/C+, SD with companion. After 3-weeks of treatment, spinal cord eCBs were analyzed using targeted lipid quantitation with liquid chromatography mass spectrometry (LCMS). We observed a 20% decrease in palmitoylethanolamide (PEA), in sickle mice compared to control mice, in R/C- group (p&lt;0.05). Further, we observed increased spinal PEA in S/C+ compared to R/C- sickle mice (~40%, p&lt;0.05), which was concomitant with reduced mechanical, heat, and cold hyperalgesia in S/C+ sickle mice group (~80%, p&lt;0.001; ~60%, p&lt;0.01; & ~30%, p&lt;0.001, respectively). Therefore, sickle diet and companionship enhances endogenous spinal PEA which has an inhibitory effect on hyperalgesia in sickle mice. Treatment of control and sickle mice in R/C- group with PEA (i.p. 20 mg/kg/day) led to acute (1 hour) reduction of mechanical- (~40%, p&lt;0.01) and cold-hyperalgesia (~40%, p&lt;0.001) in sickle mice compared to pre-treatment, which was sustained during 3 day treatment, but had no effect on control mice which do not have hyperalgesia. PEA inhibits substance P (SP)-induced mast cell activity, and sickle mice show increased spinal SP, neuronal sensitization, peripheral nerve injury and mast cell activation (Tran et al., Blood 2017). Pain in SCD is both neuropathic and inflammatory. We examined if PEA inhibited the mechanisms that underlie spinal nerve repair by neurite outgrowth inhibitor, NOGO-A/reticulon-4, which regulates nerve regeneration via Rho Kinase (ROCK) signaling. NOGO-A contributes to inflammatory pain and hyperalgesia following spinal cord injury via NOGO receptor 1 in spinal cord. We observed that spinal NOGO-A expression and ROCK activity are upregulated (20% & 100%, respectively) in sickle mice compared to control mice (all R/C-), which were inhibited upon 3-day treatment with PEA. We validated ROCK activity downstream of NOGO-A using SH-SY5Y neuroblastoma cells, simulating a sickle microenvironment with hemin (40 µM) and TNFα (1 ng/ml)(H+T). ROCK activity increased in H+T-treated SH-SY5Y cells compared to vehicle (~30%, p=0.05). In parallel, we analyzed the effect of PEA on extracellular traps (ET) in cutaneous mast cells from sickle mice induced by H+T in vitro. PEA treatment inhibited ET formation and extravasation of nuclear contents in H+T induced mast cells. Thus, PEA has the potential to attenuate neuropathic and inflammatory pain by inhibiting neuronal NOGO-A/ROCK pathway and mast cell activation in a sickle milieu. PEA has analgesic and anti-inflammatory effects on chronic pain in several clinical conditions. Therefore, our data suggest that diet and pleasure have the potential to upregulate pro-analgesic PEA that inhibits NOGO-A signaling and mast cell activation, leading to attenuation of hyperalgesia in sickle mice. Disclosures Gupta: Grifols: Research Funding; Cyclerion: Research Funding; 1910 Genetics: Research Funding; Novartis: Honoraria; Tautona Group: Honoraria; CSL Behring: Honoraria.

Increased ROCK1 not ROCK2 in circulating leukocytes in rats with myocardial ischemia/reperfusion

Background: Rho-associated protein kinase (ROCK) plays a vital role in the pathogenesis of many cardiovascular diseases. Previous studies have demonstrated that ROCK is overactivated and involved in myocardial ischemia/reperfusion in vivo. But the role of ROCK in circulating leukocytes during myocardial ischemia/reperfusion is not well studied. Material and methods: This study was performed to evaluate ROCK activity in circulating leukocytes in rats with myocardial ischemia/reperfusion injury. Myocardial ischemia/reperfusion Wistar rats were subjected to 30-min ischemia followed by 180-min reperfusion. ROCK activity in circulating leukocytes was examined by the phosphorylation state of myosin phosphatase targeting subunit 1, a substrate of ROCK. Results: ROCK activity significantly increased in leukocytes in rat ischemia/reperfusion models compared to the sham group. ROCK1 not ROCK2 level in circulating leukocytes was significantly elevated in ischemia/reperfusion. Administration of the selective inhibitor of ROCK, fasudil, significantly reduced myocardial infarct size, myocyte apoptosis, and inflammatory cytokine, including interleukin 6 and tumor necrosis factor α. Furthermore, fasudil upregulated ischemia/reperfusion-induced reduction of nitric oxide production. Conclusion: Increased ROCK1 not ROCK2 in circulating leukocytes plays a role in the pathogenesis of myocardial ischemia/reperfusion injury. Inhibition of ROCK1 in circulating leukocytes has an important role in fasudil-induced cardioprotective effects. ROCK1 in circulating leukocytes might be a new biomarker in myocardial ischemia/reperfusion injury.