Intercellular adhesion molecule-1 expression induced by interleukin (IL)-1 beta or an IL-1 beta fragment is blocked by an IL-1 receptor antagonist and a soluble IL-1 receptor

The BCR/ABL tyrosine kinase inhibitor, nilotinib, stimulates expression of IL-1β in vascular endothelium in association with downregulation of miR-3p

BCR/ABL tyrosine kinase inhibitors (TKIs) have significantly improved the prognosis for in dividuals with chronic myeloid leukemia (CML). However, many patients treated with TKIs suffer from TKI-related complications. In particular, vascular events such as peripheral artery occlusive disease have become aserious clinical problem for patients who receive the TKI, nilotinib. At present, the molecular mechanisms by which TKIs cause vascular endothelial cell insults remain unknown.This study explored the effects of the TKIs, imatinib, nilotinib and dasatinib, on vascular endothelial cells in vitro, and found that only nilotinib induced expression of interleukin-1β (IL-1β) by vascular endothelial cells. Nilotinib-induced IL-1β expression stimulated the adhesion of monocytes to vascular endothelial cells in association with an increase in levels of adhesion molecules. MicroRNA database searching identified miR-3121-3p binding sites in the 3'-UTR of the IL-1β gene. Exposure of endothelial cells to nilotinib caused downregulation of miR-3121-3p in these cells. Importantly, forced-expression of miR-3121-3p counteracted nilotinib-induced expression of IL-1β. Importantly, serum levels if IL-1β were significantly elevated in CML patients receiving nilotinib (n=14) compared to those receiving other TKIs (n=16) (3.76±1.22pg/ml vs 0.27±0.77pg/ml, p<0.05). Taken together, our data suggest that nilotinib decreases levels of miR-3121-3p resulting in an increase in expression of IL-1β and adhesion molecules in vascular endothelial cells. The miR-3121-3p/IL-1β axis could be a potential target to prevent vascular events in CML patients with high risk of vascular events.

Cyclooxygenase-2 or tumor necrosis factor-α inhibitors attenuate the mechanotransductive effects of pulsed focused ultrasound to suppress mesenchymal stromal cell homing to healthy and dystrophic muscle

Maximal homing of infused stem cells to diseased tissue is critical for regenerative medicine. Pulsed focused ultrasound (pFUS) is a clinically relevant platform to direct stem cell migration. Through mechanotransduction, pFUS establishes local gradients of cytokines, chemokines, trophic factors (CCTF) and cell adhesion molecules (CAM) in treated skeletal muscle that subsequently infused mesenchymal stromal cells (MSC) can capitalize to migrate into the parenchyma. Characterizing molecular responses to mechanical pFUS effects revealed tumor necrosis factor-alpha (TNFα) drives cyclooxygenase-2 (COX2) signaling to locally increase CCTF/CAM that are necessary for MSC homing. pFUS failed to increase chemoattractants and induce MSC homing to treated muscle in mice pretreated with ibuprofen (nonspecific COX inhibitor) or etanercept (TNFα inhibitor). pFUS-induced MSC homing was also suppressed in COX2-knockout mice, demonstrating ibuprofen blocked the mechanically induced CCTF/CAM by acting on COX2. Anti-inflammatory drugs, including ibuprofen, are administered to muscular dystrophy (MD) patients, and ibuprofen also suppressed pFUS-induced homing to muscle in a mouse model of MD. Drug interactions with cell therapies remain unexplored and are not controlled for during clinical cell therapy trials. This study highlights potentially negative drug-host interactions that suppress stem cell homing and could undermine cell-based approaches for regenerative medicine.

Interleukin-1β and interleukin-1 receptor antagonist appear in grey matter additionally to white matter lesions during experimental multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) has been mainly attributed to white matter (WM) pathology. However, recent evidence indicated the presence of grey matter (GM) lesions. One of the principal mediators of inflammatory processes is interleukin-1β (IL-1β), which is known to play a role in MS pathogenesis. It is unknown whether IL-1β is solely present in WM or also in GM lesions. Using an experimental MS model, we questioned whether IL-1β and the IL-1 receptor antagonist (IL-1ra) are present in GM in addition to affected WM regions.

METHODS

The expression of IL-1β and IL-1ra in chronic-relapsing EAE (cr-EAE) rats was examined using in situ hybridization, immunohistochemistry and real-time PCR. Rats were sacrificed at the peak of the first disease phase, the trough of the remission phase, and at the peak of the relapse. Histopathological characteristics of CNS lesions were studied using immunohistochemistry for PLP, CD68 and CD3 and Oil-Red O histochemistry.

RESULTS

IL-1β and IL-ra expression appears to a similar extent in affected GM and WM regions in the brain and spinal cord of cr-EAE rats, particularly in perivascular and periventricular locations. IL-1β and IL-1ra expression was dedicated to macrophages and/or activated microglial cells, at sites of starting demyelination. The time-dependent expression of IL-1β and IL-1ra revealed that within the spinal cord IL-1β and IL-1ra mRNA remained present throughout the disease, whereas in the brain their expression disappeared during the relapse.

CONCLUSIONS

The appearance of IL-1β expressing cells in GM within the CNS during cr-EAE may explain the occurrence of several clinical deficits present in EAE and MS which cannot be attributed solely to the presence of IL-1β in WM. Endogenously produced IL-1ra seems not capable to counteract IL-1β-induced effects. We put forward that IL-1β may behold promise as a target to address GM, in addition to WM, related pathology in MS.

The lambda interferons: guardians of the immune-epithelial interface and the T-helper 2 response

The type-III interferons (IFNs) are the most recently discovered IFNs in the human immune system and have important, but as yet poorly characterized, functions in innate and adaptive immunity that complement their antiviral functions. It is now becoming clear that these type-III IFNs have a functional niche where epithelial surfaces interact with the adaptive immune system, that their antiviral capability is not as highly developed as that of the type-I IFNs, and that they have their own profile of immunomodulatory functions; specifically, they are key modulators of the T-helper (Th)2 response.

Antagonism of the interleukin-1 receptor following traumatic brain injury in the mouse reduces the number of nitric oxide synthase-2-positive cells and improves anatomical and functional outcomes

Interleukin (IL)-1beta plays an important role in the inflammatory response that results from traumatic brain injury and antagonism of the actions of this cytokine can affect outcome. We subjected male mice to aseptic cryogenic injury and assessed recovery through anatomical, histological and functional measures following treatment with recombinant mouse IL-1 receptor antagonist (IL-1ra). A single dose (1 microg, i.c.v.) at the time of injury reduced lesion volume 3 days later, as assessed by Nissl staining, and also the number (30%) of FluoroJade-positive degenerating neurones. Mice treated with IL-1ra performed better on the beam balance and in the grid test as compared with vehicle-treated animals. Furthermore, IL-1ra-treated animals showed fewer (40%) nitric oxide synthase-2-positive cells in and around the lesion. These data suggest that activation of the IL-1 receptor following trauma contributes to the pathology and that antagonism can reduce both anatomical and functional consequences of neuroinflammation.

Biochemical mechanisms that interact with membrane-associated IL-1 RII (60-kDa decoy) receptors in populations of adherent macrophages and vascular endothelium

The aim of this investigation was to identify the potential biochemical mechanisms that alter the integrity of membrane-associated IL-1 RII (decoy) receptor complexes expressed by populations of adherent macrophages and vascular endothelium. The initial research strategy utilized to achieve this objective involved delineating the ability of macrophage activation or exposure of macrophages and vascular endothelium to a spectrum of enzyme proteases to influence the expression of membrane-associated IL-1 RII (decoy) or generate soluble fragments of this receptor complex. Results from these investigations revealed that stimulated macrophages displayed proportional increases in both the expression of membrane-associated IL-1 RII (decoy) and release of soluble receptor fragments. Exposure of macrophages and vascular endothelium to the reference proteases discovered the ability of cathepsin-D to biochemically deplete membrane-associated IL-1 RII (decoy) in addition to generating soluble fragments of this receptor complex. Complementary investigations isolated a carboxyl/aspartate protease from activated macrophages utilizing pepstatin-A affinity chromatography. Exposure of vascular endothelium to pepstatin-A binding proteins resulted in a detectable depletion of membrane-associated IL-1 RII (decoy) and generation of soluble receptor fragments. Evaluation of pepstatin-A binding proteins by SDS-PAGE identified a primary protein fraction with a molecular mass of 47-52 kDa that closely correlates with the known molecular size of leukocyte cathepsin-D fractions. Macrophage pepstatin-A binding protein fractions evaluated by nondenaturing haemoglobin-substrate PAGE (Hb-PAGE) analysis detected a lucent proteolytic band at 47-52 kDa. Macrophage pepstatin-A binding proteins also hydrolyzed a synthetic enzyme-specific substrate that selectively recognizes cathepsin-D biochemical activity. In conclusion, the leukocyte carboxyl/aspartate protease cathepsin-D can biochemically alter the integrity and generate soluble fragments of membrane-associated IL-1 RII (60-kDa decoy) receptor complexes expressed by macrophages and vascular endothelium.

Increased expression of mRNA encoding interleukin-1beta and caspase-1, and the secreted isoform of interleukin-1 receptor antagonist in the rat brain following systemic kainic acid administration

Kainic acid, an analogue of glutamate, injected systemically to rats evokes seizures that are accompanied by nerve cell damage primarily in the limbic system. In the present study, we have analyzed the temporal profile of the expression of the cytokines interleukin-1beta (IL-1beta) and IL-1 receptor antagonist (IL-1ra), and the related IL-1beta-converting enzyme (ICE/caspase-1), in different regions of the rat brain in response to peripheral kainic acid administration (10 mg/kg, i.p.). In situ hybridization histochemistry experiments revealed that IL-1beta mRNA-expressing cells, morphologically identified as microglial cells, were mainly localized to regions showing pronounced neuronal degeneration; hippocampus, thalamus, amygdala, and certain cortical regions. The strongest expression of IL-1beta mRNA was observed after 12 hr in these regions. A weak induction of the IL-1beta mRNA expression was observed already at 2 hr. Similar results were obtained by RT-PCR analysis, showing a significantly increased expression of IL-1beta mRNA in the hippocampus and amygdala after 12 hr. In addition, RT-PCR analysis revealed that IL-1ra mRNA, and specifically mRNA encoding the secreted isoform of IL-1ra (sIL-1ra), was strongly induced in the hippocampus and amygdala at 12 and 24 hr post-injection. RT-PCR analysis of mRNA encoding caspase-1 showed a significantly increased expression in the amygdala after 12 hr. In conclusion, in response to systemic kainic acid injection IL-1beta mRNA is rapidly induced and followed by induction of IL-1ra mRNA and caspase-1 mRNA, supporting a role of the IL-1 system in the inflammatory response during excitotoxic damage.

Potential mechanisms of interleukin-1 involvement in cerebral ischaemia

Interleukin-1 (IL-1) has pleiotropic actions in the central nervous system. During the last decade, a growing corpus of evidence has indicated an important role of this cytokine in the development of brain damage following cerebral ischaemia. The expression of IL-1 in the brain is dramatically increased during the early and chronic stage of infarction. The most direct evidence that IL-1 contributes significantly to ischaemic injury is that (1) central administration of IL-1beta exacerbates brain damage, and (2) injection or over-expression of interleukin-1 receptor antagonist, and blockade of interleukin-1beta converting enzyme activity reduce, dramatically, infarction and improve behavioural deficit. The mechanisms underlying IL-1 actions in stroke are not definitively elucidated, and it seems likely that its effects are mediated through stimulation and inhibition of wide range of pathophysiological processes.

The role of the hairless (hr) gene in the regulation of hair follicle catagen transformation

Mice that carry a mutation at the hairless (hr) locus develop seemingly normal hair follicles (HF) but shed their hairs completely soon after birth. Histologically, their HFs degenerate into characteristic utriculi and dermal cysts shortly after the entry of the HF into the first regression phase (catagen), during the initiation of HF cycling. Here, we show that at least nine distinct stages of HF disintegration can be distinguished in hr/hr mice. Toward the end of HF morphogenesis (day 15 postpartum) the proximal hair bulb in hr/hr skin undergoes premature and massive apoptosis. This is associated with a dyscoordination of cell proliferation in defined HF compartments, malpositioning of the proximal inner root sheath, striking atrophy of outer root sheath, and failure of trichilemmal keratinization in the developing club hair. Rather than undergoing their normal catagen-associated involution, the hair bulb and central outer root sheath disintegrate into separate cell clusters, thus disrupting all epithelial contact with the dermal papilla. Dermal papilla fibroblasts fail to migrate upward, and break up into clusters of shrunken cells stranded in the reticular dermis as dermal cyst precursors, while the upper HF epithelium transforms into utriculi. Some dermal papilla cells, which normally never undergo apoptosis, also become TUNEL+ in hr/hr skin, and their normally high expression of a key adhesion molecule, neural cell adhesion molecule, declines. Thus, loss of a functional hr gene product (a putative zinc finger transcription factor) initiates a premature, highly dysregulated catagen, which results in the destruction of the normal HF architecture and abrogates the HF's ability to cycle. This provides new insights into the pathobiology of the hr mutation, and suggests that the normal hr gene product is a crucial element of catagen control.

Expression of intercellular adhesion molecule 1 (ICAM-1) is reduced in permanent focal cerebral ischemic mouse brain using an adenoviral vector to induce overexpression of interleukin-1 receptor antagonist

Our previous studies have demonstrated that overexpression of recombinant human interleukin-1 receptor antagonist protein (IL-1ra) via gene transfer can reduce ischemic brain injury. However, the mechanism of action of IL-1ra in ischemia is unclear. Since interleukin-1 can up-regulate intercellular adhesion molecules in endothelium, the present study was designed to determine whether overexpression of the IL-1ra can reduce the expression of intercellular adhesion molecule-1 (ICAM-1) after ischemic injury. Normal saline or adenovirus vector (1x109 particles) encoding the human IL-1ra gene (Ad.RSVIL-1ra) or the Escherichia coli LacZ gene (Ad.RSVlacZ) was injected into the right lateral cerebral ventricle of adult CD-1 mice. After five days, permanent middle cerebral artery occlusion (MCAO) was achieved for 24 h using an intraluminal suture. Cerebral blood flow was monitored by transcranial laser Doppler flowmetry to verify the occlusion. ICAM-1 protein was quantified using Western blot analysis and localized using immunohistochemistry. After MCAO, surface blood flow in the ischemic hemisphere was decreased to 9-11% of the baseline. There were fewer ICAM-1 positive vessels in the ischemic cortex of the Ad.RSVIL-1ra transfected mice than in the Ad.RSVlacZ transfected and saline treated mice (138+/-19 vs. 249+/-25, 284+/-22, p<0.05). Western blot analysis shows that ICAM-1 protein decreased 50-60% in the Ad. RSVIL-1ra group compared to the other two groups. There were no significant differences in the numbers of positive vessels in the ischemic basal ganglia and contralateral hemisphere among the three groups. Our studies suggest that IL-1ra overexpression can down-regulate the expression of ICAM-1 in the ipsilateral cortex in ischemic mice. Interleukin-1 may play an important role in the activation of inflammatory reaction during focal cerebral ischemia by promoting leukocyte adhesion on the endothelium cells.

Regulation by interleukin-1beta of formation of a line of delimiting astrocytes following prenatal trauma to the brain of the mouse

The regulation of perinatal glia limitans (GL) reformation by interleukin-1beta (IL-1beta) following prenatal neural trauma in the mouse was studied in lesioned fetal mice by immunocytochemistry and computer-assisted image analysis for presence and distribution of astrocytes and IL-1beta immunoreactivity (ir). Astrocytes stained with anti-glial fibrillary acidic protein (GFAP) were observed as a line of delimiting astrocytes (LDA) near the lesion edge on Postnatal Day 0 (P0, 2 days postlesion). At P6, a new and complete GL composed of GFAP-positive astrocytes was continuous with that of adjacent undamaged tissue. The new GL was located in the same area at P6 as was the LDA at P0, suggesting that the LDA is the precursor structure to a reformed GL. Astrocytes comprising the new GL were positive for anti-IL-1beta. The IL-1 receptor antagonist (IL-1ra), administered acutely into the lesion, produced a significantly decreased optical density of IL-1beta-ir at the LDA at P0 compared to animals that received injections of vehicle, human recombinant IL-1beta, or a combination injection of IL-1ra + IL-1beta. Furthermore, although GFAP-stained cells appeared at the lesion site, an organized LDA was not visible at P0 in IL-1ra-treated animals. Vehicle-, IL-1beta-, and combination-injected animals showed a robust LDA at the lesion site at P0. These data suggest that upregulation of IL-1beta in astrocytes and interaction of IL-1beta with the neural IL-1 receptor are important for reconstruction of the GL following prenatal lesion in the murine brain.

Production of interleukin-1 receptor antagonist by human glioblastoma cells in vitro and in vivo

We investigated the expression and production of the interleukin-1 receptor antagonist (IL-1ra) in three human glioblastoma cell lines (LN443, LN444, LN859). Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated the expression of IL-1ra mRNA transcripts in the three cell lines. These three cell lines also expressed mRNA for IL-1 alpha, IL-1 beta, as well as IL-1 receptor type I and type II, suggesting the presence of an IL-1 autocrine loop in these cell lines. Northern blot analysis demonstrated that the IL-1ra mRNA expression increased with IL-1 beta or tumor necrosis factor (TNF)-alpha but not with GM-CSF stimulation in both LN443 and LN444 cell lines. PMA stimulation increased the mRNA expression in LN444 but not in LN443 cells. Immunocytochemical staining showed IL-1ra immunoreactivity in these three cell lines. ELISA on culture supernatants demonstrated that the IL-1ra was secreted from the cell lines in agreement with the mRNA expression. RT-PCR with isoform-specific primers showed that both intracellular and secreted forms of IL-1ra were expressed by the three cell lines, with a predominance of the intracellular form. In vivo study with RT-PCR and Northern blot analysis demonstrated IL-1ra mRNA in six out of 12 human glioblastoma and two out of five anaplastic astrocytoma tissues, although the expression level was not high in some cases. Immunohistochemistry demonstrated the presence of IL-1ra within the cytoplasm of tumor cells in six out of 10 glioblastomas in vivo. These results suggest a potential role of IL-1ra in regulation of the IL-1 autocrine loop in glioblastomas.