“Although a hypothesis conceived many years ago, the terminals of receptor neurons are thought to contain branches of nerve fibers without any apparent structural specialization… only recently have we begun to understand the molecular basis of thermoreception by cells. All neurons and ion channels are affected by changes in temperature, not least because channel gating is generally a temperature-dependent process. However, only some neurons can be called thermoreceptors and very few ion channel types can be designated as thermosensors.” (1)
“Thermoreceptors are sensitive to changes in temperature rather than to the value of the temperature itself, probably due to their characteristic strong adaptation.”
Molecular Origin of Thermosensitivity:
“The mechanism by which temperature modulates TRP channels is still unclear, yet several
hypotheses have been proposed:
• changes in temperature could produce a ligand that binds to a receptor and affects the channel
• changes in temperature could produce a structural change in the channel that provokes its opening
• temperature changes could affect the structure of the membrane, causing changes in tension that would in turn affect ion channels.
“Because capsaicin induces burning pain, it has been hypothesized that both capsaicin and heat may use a common mechanism to activate TRPV1 and produce pain. Both stimuli affect excised patches, and in general, it is accepted that TRPV1 is directly activated by noxious-heat, so that it can be considered a true heat sensor.” (1)
“There is already sufficient data supporting the role of TREK and TRP channels in two fundamental aspects of the response to temperature. On the one hand, they are responsible for capturing the thermal sensation at the peripheral level, acting as thermosensors in thermoreceptive neurons or keratinocytes. On the other hand, yet no less important, they help regulate body temperature and allow neurons in the hypothalamus to become internal thermoreceptors.”
“Distribution of transient receptor potential (TRP) and TWIK-related potassium (TREK) channels as a function of their temperature threshold. Note that while TREK channels are activated by increases in temperature (orange), TRP channels may also be activated by lowering the temperature (blue).” (1)
“In general, TREK channels display very weak activity at room temperature and normal pressure, even when overexpressed in heterologous systems. However, their activity increases strongly when a number of channels to that of TRP channels… Other thermosensitive proteins have also been described, like the Na/K ATPase and ENaC channels, or P2X receptors, and while these should also receive attention, we consider this to fall beyond the scope of this review. Indeed, cell thermosensitivity seems to be governed by the interplay of a number of channel types, as reported in hypothalamic neurons.” (1)
“TRP channels are generally accepted as the primary thermosensors; however, several lines of evidence indicate that other channels are necessary to explain the full plethora of mechanisms involved in thermosensation. TREK2 channels appear to be important in thermoreception at moderate temperatures and sensing innocuous cold but not aversive cold, while TREK1 and TRAAK acting together may be important in sensing painful cold.” (1)
“There are several important differences between the two main types of thermosensor channels that have been reviewed in this article:
1. First, TREKs are potassium channels with negative reversal potentials, such that their activation would result in a reduction in thermoreceptor activity. By contrast, as the reversal potential of TRPs (cationic channels) is close to 0 mV, their activation will result in increased thermoreceptor excitability.”
2. “Second, the three TREK channels appear to increase their open probability as temperatures increase, while there are two possible situations in the case of TRPs: one in which its activity increases by increasing the temperature; and another in which activity increases when the temperature decreases. Although the activation of these channels generates opposing effects on thermoreceptors (depolarization versus hyperpolarization), the information available to date regarding the participation of TRP and TREK channels in thermosensitivity strongly suggests that both types of channels collaborate and complement each other to generate the sensations of heat, cold, and thermal pain.” (1)
“Blockade of TRPV1 can attenuate morphine tolerance and inhibit morphine conditioned place preference (CPP) in rodents. In addition, blocking TRPV1 also suppresses cocaine-seeking behavior in a cocaine-primed relapse. Moreover, our previous work found that repeated methamphetamine (MAP) treatments can induce up-regulation of TRPV1 mRNA expression in the frontal cortex. Taken together, these data indicate that TRPV1 could be a target of the rewarding effects of MAP.” (21)
“The analgesic effect of ARA 290 is mediated by its anti-inflammatory and immunomodulatory functions, or more specifically, by targeting the innate repair receptor (IRR) to down-regulate inflammation to alleviate neuropathic pain. However, whether other mechanisms or pathways are involved in ARA 290-mediated analgesic effect remains elusive. In this study, we are particularly interested in whether ARA 290 could directly target peripheral nociceptors by blocking or influencing receptors in pain sensation. Using calcium imaging, cell culture and behavioral tests, we demonstrated that ARA 290 was able to specifically inhibit TRPV1 channel activity, and relieve the mechanical hypersensitivity induced by capsaicin.” (22)
“In vehicle-treated controls, relative vascular area (RVA) was assessed both at the wound center and edge, which was observed to decrease sharply very early postburn and reached a nadir by 24–48 h. In contrast, ARA290-treated groups increased RVA values by ∼10-fold in the center and ∼threefold at the edge of the wounds at the 48 h time point. Thus, ARA290 prevented the progressive loss of the wound bed vasculature.” (2)
Control vs. ARA-290 (2):
“We also investigated the effect of ARA290 on leukocyte adhesion behavior, which is an important factor of tissue infiltration and/or microvascular injury due to interactions with the vascular endothelium. TNF-α and interleukin (IL)-1β are known to induce cell adhesion molecules (CAMs) on the surface of the endothelium and circulating leukocytes along with other actions that cause hypercoagulability. Therefore, it is plausible that suppression of the TNF-α–driven response by ARA290 could impact on leukocyte–endothelial adhesion in the wounds. We measured gene expression of two cell CAMs, platelet endothelial CAM–1 (PECAM-1; CD31), and vascular CAM–1 (VCAM-1; CD106).” (2)
“In vehicle controls, the wound center exhibited an early rise in TNF-α followed by a sharp drop at 24 h, consistent with the relatively rapid and extensive tissue necrosis in this area, whereas at the wound edge, which maintained perfusion longer, TNF-α levels peaked at 24 h and then decreased at 48 h. Conversely, wounds in the ARA290 treatment group exhibited completely different dynamics, with absence of early TNF-α spike, despite abundant cellular infiltrates, but rather a slow and progressive rise in TNF-α levels over time” (3)
“Following dosing, the ARA 290 group improved significantly compared with the placebo group with an improvement of 3.3 points in the ARA 290 group versus 1.1 points for placebo. The difference between the groups increased when evaluated at d 56 (28 d following last dose) at which point the mean improvement in the ARA 290 had increased to 4.2, and the placebo group diminished to 0.74 points. Significant improvements were observed in the “tingling,” “thermal pain” and “allodynia” categories, as well as a trend for improvement in the categories of “pressure pain” and “pain attacks” in the ARA 290 group, but not in the placebo group. No difference was observed before and after ARA 290 treatment in the “burning” category”. (3)
“…ARA 290 treatment was associated with significantly reduced ratios of total serum cholesterol to high density lipoprotein (HDL)-cholesterol and serum triglyceride levels. There was an increase in HDL in the ARA 290 group compared with the placebo group at 28 and 56 d. Similar to the Hb A1c results, the change in triglyceride concentration depended upon the baseline value for the ARA 290 group but not for the placebo group.” (3)
“ARA 290 administration is associated with an improvement in Hb A1c at d 28 and is maintained at least 4 wks following dosing. The A1c percentage decreased significantly from baseline in the group receiving ARA 290 (4 mg SC daily for 28 d; filled circles), whereas the placebo group (open circles) remained unchanged. Follow-up at an additional 28 d showed the ARA 290 treatment group maintained an improved A1c profile.” (3)
“In GK rats receiving ARA290 daily for up to 4 weeks, plasma glucose concentrations were lower after 3 and 4 weeks, and HbA1c was reduced by ∼20% without changes in whole body and hepatic insulin sensitivity. Glucose-stimulated insulin secretion was increased in islets from ARA290-treated rats.” (4)
“ARA290 also improved stimulus-secretion coupling for glucose in GK rat islets, as shown by an improved glucose oxidation rate, ATP production, and acutely enhanced glucose-stimulated insulin secretion.” (4)
“Finally, inhibition of protein kinase A completely abolished effects of ARA290 on insulin secretion. In conclusion, ARA290 improved glucose tolerance without affecting hematocrit in diabetic GK rats. This effect appears to be due to improved β-cell glucose metabolism and [Ca2+]i handling, and thereby enhanced glucose-induced insulin release.” (4)
“ARA290 treatment was able to decrease neuritic dystrophy by 55-74% compared to untreated diabetics or in comparison to a separate group of diabetic animals representing the 4 month treatment onset point. Surprisingly, there was no effect of ARA290 on ganglionic neuron number or ongoing neuronopathy (pale/degenerating neurons) in diabetic Akita mice during this time period.” (9)
“Erythropoietin (EPO) is a cytokine that regulates hematopoiesis mediated by its binding to the erythropoietin receptor (EPOR), that is present also in non-erythroid tissues, including pancreatic islets. In addition to its hematopoietic action, EPO has been shown to exert anti-inflammatory, anti-apoptotic and cytoprotective effects in a wide variety of cell types by binding to the innate repair receptor (IRR) which is a heteromer of EPOR and CD131, the β common receptor. EPO treatment has been shown to protect against diabetes development in streptozotocin-induced and db/db mouse models of type 1 and type 2 diabetes, respectively, while exerting anti-apoptotic, anti-inflammatory, proliferative and angiogenic effects within the islets.” (4)
“Since prolonged treatment with EPO can increase the hematocrit and provoke thrombosis, we have studied an EPO analogue, ARA290. This 11 amino acid peptide lacks hematopoietic action, binds to the IRR and protects a number of tissues in response to injury. A recent phase 2 clinical trial evaluating ARA290 in patients with type 2 diabetes and painful neuropathy showed that ARA290 significantly reduced HbA1c levels as well as neuropathic symptoms.” (4)
“ARA290 increased glomerular filtration rate during the observation period of seven days. Furthermore, ARA290 tended to reduce MCP-1 and IL-6 expression 15 minutes post-reperfusion. Seven days post-reperfusion ARA290 reduced interstitial fibrosis.” (6)
“Furthermore, ARA290 and EPO were able to increase phosphorylation of eNOS. The effect of ARA290 on these pathways could explain both the anti-inflammatory capacities and the effect on renal function.” (6)
“ARA290 improved renal function. Plasma creatinine levels of all animals increased in the first 24 hours after reperfusion. After the first day, plasma creatinine levels declined during the remaining 6 days. Plasma creatinine levels and urine flow did not differ between vehicle- and ARA290 treated animals. The glomerular filtration rate (GFR) of the I/R kidney was calculated based on daily plasma creatinine levels and 24-hours urine via the cannulated ischemic kidney. The GFR of the I/R kidney was markedly increased by ARA290 treatment post-reperfusion in the first seven days post-reperfusion. No differences were found in haemoglobin, haematocrit, urea or aspartate transaminase plasma levels. No cardiovascular adverse events were observed in vehicle- or ARA290 treated animals.” (6)
ARA-290 treated kidney are in pictures B and D, non-treated groups are A and B:
ARA-290 reduced TGA-beta expression and alpha-SMA mRNA expression in diseased kidney:
“Based on the results of this study, ARA290 is a promising drug to prevent I/R injury and to improve renal function rapidly following renal transplantation.” (6)
“ARA290 protects against early renal allograft injury in rats by reducing macrophage infiltration, improving renal morphology, inhibiting mRNA expression of inflammatory mediators, and weakening the binding affinity of NF-kB to DNA.” (11)
”The innate repair receptor (IRR) is a heteromer of the erythropoietin receptor and the b-common (CD131) receptor, which simultaneously activates anti-inflammatory and tissue repair pathways. Experimental data suggest that after peripheral nerve injury, the IRR is upregulated in the spinal cord and modulates the neurogenic inflammatory response. The recently introduced selective IRR agonist ARA290 is an 11-amino acid peptide initially tested in animal models of neuropathy. After sciatic nerve injury, ARA290 produced a rapid and long-term relief of mechanical and cold allodynia in normal mice, but not in animals with a b-common receptor knockout phenotype.” (5)
“Forty-eight T2D patients with moderate to severe SFN-induced chronic pain were treated with daily subcutaneous injections of ARA290 4 mg or placebo for 28 days. The results of the trial were similar to those obtained earlier in sarcoidosis patients with improvements in neuropathic symptoms, an increase in CNFD in patients with an initial reduction in CNFD.”
“Despite a large reduction of allodynia maintained during the intensive treatment period, a slow trend toward an increase in pain behavior was observed during the weekly ARA 290 dosing paradigm. This observation could suggest that because of the biologic half-life of ARA290 of less than 1 week, more frequent dosing could prevent the trend for increased pain. An alternative explanation could be that noninflammatory processes slowly develop to foster proallodynic responses and gain in importance over time or that the inflammatory response becomes more resilient. If true, this suggests that treatment of neuropathic pain caused by nerve injury should be aimed at targeting multiple processes, of which suppression of the immune response is one that requires early (and continuous) treatment. It is not likely that decreasing the interval between nerve injury and the initiation of treatment or using ARA290 as a preemptive measure results in a more effective relief of neuropathic pain because the EPOR-cR complex is being up-regulated secondary to tissue damage. Alternatively, more intense treatment during the initial phase (e.g., higher doses or injections at a 1-day interval) may be more effective in neutralizing the initial hit induced by the peripheral nerve injury.” (7)
3“Innate repair receptor activation reduces mechanical allodynia after spared nerve injury (SNI) in the rat. Animals were sham operated (blue) or received SNI and vehicle (grey) or SNI and 60 mg/kg ARA290 (red), both administered on days 1, 3, 6, 8, and 10 postsurgery…” (5)
”In patients with sarcoidosis, ARA290 significantly improved neuropathic and autonomic symptoms, as well as quality of life as assessed by the small fiber neuropathy screening list questionnaire. In addition, ARA290 treatment for 28 days initiated a regrowth of small nerve fibers in the cornea, but not in the epidermis.” (5) “The results of the NERVARA trial indicate a significant increase in corneal nerve fiber area by 14% within the 4-week treatment period (relative to a small decrease after placebo treatment) without affecting proximal and distal limb intraepidermal nerve fiber densities.16 These data are important for 2 reasons. First, ARA290 initiates a rapid regrowth of small nerve fibers in the cornea, which is a sign of tissue healing and restoration as earlier observed in experimental studies… the corneal nerve fibers seem to be more sensitive to regeneration than skin fibers, and consequently, the cornea is the more appropriate location to assess not only the state of small fiber pathology but also assess the effect of treatment.”
What is sarcoidosis?: “Sarcoidosis is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomas. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly affected are the eyes, liver, heart, and brain.” (19)
What is a granulomatous papule?: “A granuloma is a structure formed during inflammation that is found in many diseases. It is a collection of immune cells known as macrophages. Granulomas form when the immune system attempts to wall off substances it perceives as foreign but is unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as foreign objects, keratin and suture fragments.” (20)
“After sciatic nerve injury, ARA290 produced a rapid and long-term relief of mechanical and cold allodynia in normal mice, but not in animals with a b-common receptor knockout phenotype. In humans, ARA290 has been evaluated in patients with small fiber neuropathy associated with sarcoidosis or type 2 diabetes (T2D) mellitus. In patients with sarcoidosis, ARA290 significantly improved neuropathic and autonomic symptoms, as well as quality of life as assessed by the small fiber neuropathy screening list questionnaire. In addition, ARA290 treatment for 28 days initiated a regrowth of small nerve fibers in the cornea, but not in the epidermis. In patients with T2D, the results were similar to those observed in patients with sarcoidosis along with an improved metabolic profile. In both populations, ARA290 lacked significant adverse effects. These experimental and clinical studies show that ARA290 effectively reprograms a proinflammatory, tissue-damaging milieu into one of healing and tissue repair. Further clinical trials with long-term treatment and follow up are needed to assess the full potential of IRR activation by ARA290 as a disease-modifying therapy in neuropathy of various etiologies.” (5)
“Indeed, in unilateral nerve damage, a bilateral increase in TNF- and activated glia cells in bilateral homo- and heteronymous dorsalroot ganglia is observed in a rat model of chronic constriction injury, suggesting a more generalized inflammatory response.” (7)
“…members of the transient receptor potential channel family, especially transient receptor potential vanilloid 1 (TRPV1), play a critical role in initiating and maintaining neuroinflammation. Although the release of proinflammatory mediators from nociceptive neurons initiates a glial response, the activated microglia subsequently maintain and amplify the inflammatory response by the release of chemokines and cytokines (eg, interleukins 1b and 6, TNF-a).19,20,40,48 Importantly, the inflammatory response is not restricted to the level of the nerve injury but also moves in a cranial and caudal direction with concomitant symptoms of spreading mechanical allodynia.”” (5)
“The proposed cytoprotective pathway of the EPOR2-βcR2 receptor complex is the Janus kinase-2 (JAK-2) pathway. In vitro it has been shown that the JAK-2 pathway is required for protection by EPO. Phosphorylation of JAK-2 results in potent anti-inflammatory and anti-apoptotic effects. ARA290 influences downstream pathways of JAK-2, such as activation of pro-survival pathway Akt and inhibition of pro-inflammatory pathways p38 mitogen activated protein kinase, glycogen synthase kinase-3β and nuclear factor-κβ.” (6)
Neuroprotection: “There is ample evidence that after peripheral nerve injury, as induced in our current study, an innate immune response is triggered in the spinal cord in which proinflammatory cytokines, including TNF-, are released. This neuroinflammatory response is highly self-amplifying, causing collateral damage to surrounding tissue and leading to sensitization of primary affected and secondary neurons, enhancing allodynia, hyperalgesia, and spontaneous pain. An important issue in this respect is the short half-life of ARA290 (plasma half-life 2 min in rats and rabbits).17 Although this suggests a peripheral rather than a central effect, there is ample evidence that ARA290 passes the blood–brain barrier. For example, ARA290 is able to cross the blood–brain barrier to exert its neuroprotective effects in ischemic stroke models and passes the blood–retinal barrier, reducing retinal edema in diabetic animals.” (7)
Traumatic Brain Injury and Encephlitilits: “ARA290 significantly improved neurological recovery when given at 3 hrs post-injury, and despite the short half-life continuous infusion of ARA290 did not provide better outcome.” (10)
Microglia suppression and NMDA antagonism: “Since the activation or recruitment of microglia is largely mediated through the local production of CCL2, a possible scenario is that ARA 290 reduces the release of CCL2 via activation of the IRR on neuronal and immune cells. However, both at 2 and 20 weeks after SNI and ARA 290 treatment, relief of allodynia was not complete, indicating that the central response to peripheral nerve damage involves multiple systems including neuroinflammation and probably also up-regulation of excitatory pathways and synaptic plastic changes. Of interest is that ARA 290 treatment causes a reduction in NMDA mRNA (subunits NR1, NR2A and NR2B) in SNI animals, suggestive of an additional role, apart from immune-modulation, for ARA 290 in the treatment of neuropathic pain by suppression of excitatory glutamatergic activity… ARA 290 dose dependently reduces allodynia coupled to suppression of the spinal microglia response.” (17)
“EPO inhibits T-cell proliferation, expansion, and IFN-y production… Together, the functional and biochemical data support the conclusion that EPO-induced inhibition of T-cell proliferation is mediated through signals transmitted directly through the EPO-R expressed on the T cell.” (8)
“In separate experiments, we tested whether EPO alters T helper cell 1 (Th1)/Th2 differentiation in vitro. At the highest concentrations tested, EPO partially inhibited IFN-y production under Th1 polarizing conditions (antiCD3/anti-CD28+, IL-12, and blocking anti–IL-4 mAb) but did not inhibit IL-4 production under Th2 polarizing conditions (IL-4+blocking anti–IL-12/anti–IFN-g mAb)” (9)
“ARA 290 intervention altered Th cell differentiation in EAN.” (12):
“ARA290 tended to reduce an early increase of IL-6 and MCP-1 mRNA expression at 15 minutes post-reperfusion relative to the baseline…” (12)
“…ARA 290 significantly suppressed lymphocyte proliferation, which may at least partly contribute to the reduced T cell numbers in spleen and therefore disease severity in EAN rats. Furthermore, in EAN, ARA 290 inhibited Th1 and Th17 polarization and promote Th2 and Treg differentiation.” (12)
“EAN is considered to be mainly mediated by Th1 cells and Th1 cytokines, such as IFN-c or TNF-a. In addition, Th17 cells were believed to contribute to the development of EAN and GBS as well. Th2 cells that may suppress cell-mediated immunity and regulatory T cells that can suppress the activation of the immune system may contribute to the resolution of EAN. Therefore, ARA 290 signal can also alter Th differentiation to favour EAN recovery.” (12)
“As anticipated, IL-2 significantly augmented anti-CD3/anti-CD28–induced T-cell proliferation. Strikingly, EPO blocked the IL-2–induced proliferative effect without altering T-cell surface expression levels of the IL-2R. IL-2R signaling is transduced through multiple parallel pathways, including phospho-STAT5 and AKT. EPO inhibited phosphorylation of AKT when we added recombinant IL-2 to the culture wells.” (8)
“EPO inhibits T-cell expansion. (A) Kinetics of EPO-R gene expression in total T lymphocytes after anti-CD3/anti-CD28 stimulation as assessed by quantitative RT-PCR (means+SEMs; two experiments in triplicate). (B) Representative flow cytometry histograms and (C) quantified changes in mean fluorescence intensities (MFIs) versus baseline of EPO-R expression on the cell surface of CD4+ and CD8+ T lymphocytes after 24, 48, or 72 hours of anti-CD3/anti-CD28 stimulation (means+SEMs; eight experiments). (D) Representative flow cytometry histograms and (E) MFI (fold increase over isotype) of EPO-R on monocytes and immature and mature moDCs (means+SEMs; four experiments). (F) Representative plots and (G) quantitation of human PBMCs stimulated with anti-CD3/antiCD28 gated on CD4+ or CD8+ T cells in the presence of EPO at the indicated doses (or vehicle control; means+SEMs; four experiments). *P,0.05; **P,0.01 versus 0 hours, isotype, or vehicle.” (8)
“ARA290 tended to reduce an early increase of IL-6 and MCP-1 mRNA expression at 15 minutes post-reperfusion relative to the baseline…”
“In separate experiments, we tested whether EPO alters T helper cell 1 (Th1)/Th2 differentiation in vitro. At the highest concentrations tested, EPO partially inhibited IFN-y production under Th1 polarizing conditions (antiCD3/anti-CD28+, IL-12, and blocking anti–IL-4 mAb) but did not inhibit IL-4 production under Th2 polarizing conditions (IL-4+blocking anti–IL-12/anti–IFN-g mAb)” (9)
EPO Prevents Expansion of Alloreactive Naïve CD4+ T Cells In Vivo: “To test whether and how these in vitro findings apply in vivo, we transferred CFSElabeled naïve human CD4+ T cells into NOD scid ycnull recipients, which are deficient in T, B, and natural killer cells.13 In this model, the human T cells proliferate in vivo in response to xenogeneic murine antigens. Groups of animals were treated with EPO or vehicle control. Three days later, we examined splenic T-cell responses by flow cytometry. These assays remarkably revealed less human T-cell proliferation (higher frequency of nondivided CFSEhi human T cells) and diminished IFN-g production in the EPO-treated animals.” (8)
“ARA 290 intervention suppressed demyelination and promoted remyelination of sciatic nerves.” (12)
“ARA 290 exerted direct proliferation promotion and anti-inflammatory effects on Schwann cells.” (12)
“ARA 290 intervention reduced inflammatory cell infiltration and altered inflammatory cytokines expression in sciatic nerves.” (12)
“…the number of perivascular lesions and the infiltration of mononuclear cells in spinal cords of ARA290-treated EAE rats was significantly decreased compared to the PBS-treated control group.” (18)
“Our in vitro experiments showed that ARA 290 dosedependently suppressed LPS-induced inflammatory activation of RAW264.7 macrophage by reducing TNF-a levels. Interestingly, our results here also showed that ARA 290 greatly increased the phagocytic capacity of macrophages, which is essential to remove apoptotic cells and debris to promote EAN remission, in a dose-dependent way in vitro.” (12)
Activated autoreactive helper T cells are of importance for the initiation of EAN. Activated macrophages cause demyelination by direct phagocytic attack and secretion of inflammatory mediators. In peripheral nerves of EAN rats, cytokines are produced and released by many cell types and regulate inflammation and immunity.” (12)
“Specifically, we saw that ARA290 was able to overcome a TNFα-mediated inhibition of transcription factor activation related to cell stress responses, most notably of serum response factor (SRF), heat shock transcription factor protein 1 (HSF1), and activator protein 1 (AP1).” (14)
“The diagram [below] depicts actions taken when a stress is introduced to the cell. Stress will induce HSF-1 and cause proteins to misfold. Molecular chaperones will aid these proteins to fold correctly or if the degree of misfolding is too severe, the protein will be eliminated through the proteasome or autophagy.” (14):
“Protein folding is already challenging due to the crowded intracellular space where aberrant interactions can arise; it becomes more difficult when environmental stressors can denature proteins and cause even more non-native folding to occur. If the work by molecular chaperones is not enough to prevent incorrect folding, the protein may be degraded by the proteasome or autophagy to remove any potentially toxic aggregates. Misfolded proteins, if left unchecked, can lead to aggregation that prevents the protein from moving into its proper conformation and eventually leads to plaque formation, which may be seen in various diseases. Heat shock proteins induced by the HSR can help prevent protein aggregation that can lead to common neurodegenerative diseases such as Alzheimer’s, Huntington’s, or Parkinson’s Disease.” (14)
“When a stress occurs, these chaperones are released due to the presence of denatured proteins and various conformational changes to HSF1 cause it to undergo nuclear localization where it becomes active through trimerization. Newly trimerized HSF1 will bind to heat shock elements (HSE) located in promoter regions of different HSPs to activate transcription of HSP mRNA. The mRNA will eventually be transcribed and comprise the upregulated HSPs that can alleviate the stress at hand and restore proteostasis. HSF1 will also regulate expression of HSPs through epigenetic modifications.” (14)
“The administration of ARA290 to pristane-induced SLE and MRL/lpr mice significantly suppressed the level of serum antinuclear autoantibodies (ANAs) and anti-dsDNA autoantibodies, reduced the deposition of IgG and C3, and ameliorated the nephritis symptoms. Moreover, the serum concentrations of inflammatory cytokine IL-6, MCP-1 and TNF-a in SLE mice were reduced by ARA290. Further, ARA290 decreased the number of apoptotic cells in kidney. In vitro experiment revealed that ARA290 inhibited the inflammatory activation of macrophages and promoted the phagocytotic function of macrophages to apoptotic cells.” (15)
“ARA290 ameliorated Systemic lupus erythematosus (SLE), which at least could be partly due to its anti-inflammatory and apoptotic cell clearance promoting effects, without stimulating haematopoiesis, suggesting that ARA290 could be a hopeful candidate for SLE treatment.” (15)
“Therapeutic ARA290 treatment reduced MNC numbers in peripheral lymph nodes of EAE rats. EAE rats (n = 3) received ARA290 (35 μg/kg) or PBS treatment from Day 7 to 12. The spleen and lymph node were obtained on Day 13. A) Significantly enlarged spleen was observed in PBS-treated EAE rat (left), whereas smaller spleen was found in ARA290-treated EAE rat (right). After lysis of red blood cells (RBCs), the total number of MNCs was quantified from single cell suspensions of the spleen. Greatly increased MNC numbers were found in PBS-treated EAE spleen compared to the spleen from ARA290-treated EAE rat. B) The lymph node from ARA290-treated EAE rat (right) was much smaller than the one from PBS-treated EAE rat (left). The total number of MNCs was quantified from single cell suspensions of lymph node. Significant decreased MNC numbers were observed in ARA290-treated EAE lymph node compared to the lymph node from PBS-treated EAE rat.” (18)
“The upregulation of tissue-protective receptor complex of erythropoietin (EPO) in critical limb ischemia (CLI) shows that, theoretically, it is possible to use EPO in CLI for tissue protection. Because EPO is thrombogenic in its native form, we have shown that nonhematopoietic EPO derivatives are equally effective in decreasing myotube cell death and inflammation in cell culture.” (16)
“Therapeutic ARA290 treatment inhibited the expression of inflammatory cytokines in spinal cords of EAE rats.” (18)
“Reduced frailty of ARA290 is consistent with improved healthspan. Concurrently, ARA290 preserves autonomic modulation of Heart Rate (HR) and Ejection Fraction (EF) with age. Because decreases in these markers predicted significantly higher risks for mortality, ARA290’s impact on cardiac function with age may contribute to the improvement in healthspan” (13)
“ARA290 slowed the decline in basal heart rate (BHR) with age (p b 0.03)… Ejection fraction (EF) declined 0.469% per month slower in ARA290 (p b 0.005). At 33 months EF was 7.5% greater in ARA290 (p b 0.004).” (13)
“We observed an increase in peak [Ca2+]i values in ARA 290-treated islets during stimulation by 200 µM carbamylcholine, in the presence or in the absence of extracellular Ca2+ , as compared with the vehicle-treated islets… There was no statistically significant difference in Ca2+ entry…” (4)
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