cDNA cloning and mapping of a novel islet-brain/JNK-interacting protein

A novel circular RNA, circMAML3, promotes tumor progression of prostate cancer by regulating miR-665/MAPK8IP2 axis

Many studies have now demonstrated that circRNAs are aberrantly expressed in cancer and are involved in the regulation of malignant tumor progression. However, the role of circMAML3 (hsa_circ_0125392) in prostate cancer has not been reported. circMAML3 was selected from public data through screening. The circMAML3 circular characterization was performed using Sanger sequencing, agarose gel electrophoresis assay, RNase R assay and actinomycin D assay. The expression of circMAML3 in prostate cancer tissues and cells was detected by qRT-PCR. In vivo and in vitro experiments were conducted to investigate the biological functions of circMAML3 in prostate cancer. Finally, the underlying mechanism of circMAML3 was revealed by qRT-PCR, luciferase reporter assay, miRNA Pulldown, RNA immunoprecipitation, western blotting, and rescue assay. Compared to normal prostate tissue and prostate epithelial cells, circMAML3 is highly expressed in prostate cancer tissues and cell lines. CircMAML3 overexpression promotes prostate cancer proliferation and metastasis, while knockdown of circMAML3 exerts the opposite effect. Mechanistically, circMAML3 promotes prostate cancer progression by upregulating MAPK8IP2 expression through sponge miR-665. Our research indicates that circMAML3 promotes prostate cancer progression through the circMAML3/miR-665/MAPK8IP2 axis. circMAML3 and MAPK8IP2 are upregulated in prostate cancer expression and play an oncogenic role, whereas miR-665 is downregulated in prostate cancer and plays an oncogenic role. Therefore, CircMAML3 may be a potential biomarker for prostate cancer diagnosis, treatment and prognosis.

MAPK8IP2 is a potential prognostic biomarker and promote tumor progression in prostate cancer

Background

MAPK8IP2 is one of the JNK-interacting proteins (JIPs) family members, and is involved in the regulation of the JNK and P38 MAPK signaling pathways. MAPK8IP2 has been reported to be closely associated with several cancers. However, the biological function of MAPK8IP2 in prostate cancer (PCa) remains unclear.

Methods

MAPK8IP2 expression in PCa and subgroups of PCa was analyzed by public databases. The prognostic role of MAPK8IP2 in prostate cancer was analyzed using the Cox regression method. The potential mechanism by which MAPK8IP2 affects PCa progression was investigated by utilizing public data, including genetic alteration, DNA methylation, m6A methylation, and immune infiltration data. We further performed in vitro assays to validate the effect of MAPK8IP2 on PCa cell proliferation, migration and invasion.

Results

MAPK8IP2 is highly expressed in PCa tissues. Overexpression of MAPK8IP2 is associated with adverse clinicopathological factors and a poor prognosis in PCa. Receiver operating curve analysis showed that MAPK8IP2 can distinguish PCa tissues from non-PCa tissues with a certain accuracy (AUC = 0.814). The MAPK8IP2 genetic alteration rate was 2.6% and MAPK8IP2 alterations correlated with a poor prognosis. We also found that CDK12 and TP53 mutations were associated with MAPK8IP2 expression. The DNA methylation level of MAPK8IP2 was higher in primary tumors than in normal tissues, and the high MAPK8IP2 DNA methylation group of PCa patients had poor survival. Enrichment analysis indicated that MAPK8IP2 was involved in the MAPK signaling pathway. In vitro, knockdown of MAPK8IP2 inhibited PCa cell proliferation, migration and invasion.

Conclusion

MAPK8IP2 is a potential target for PCa treatment and can serve as a novel biomarker for PCa diagnosis and prognosis evaluation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10259-2.

The Cerebellar Involvement in Autism Spectrum Disorders: From the Social Brain to Mouse Models

Autism spectrum disorders (ASD) are pervasive neurodevelopmental disorders that include a variety of forms and clinical phenotypes. This heterogeneity complicates the clinical and experimental approaches to ASD etiology and pathophysiology. To date, a unifying theory of these diseases is still missing. Nevertheless, the intense work of researchers and clinicians in the last decades has identified some ASD hallmarks and the primary brain areas involved. Not surprisingly, the areas that are part of the so-called “social brain”, and those strictly connected to them, were found to be crucial, such as the prefrontal cortex, amygdala, hippocampus, limbic system, and dopaminergic pathways. With the recent acknowledgment of the cerebellar contribution to cognitive functions and the social brain, its involvement in ASD has become unmistakable, though its extent is still to be elucidated. In most cases, significant advances were made possible by recent technological developments in structural/functional assessment of the human brain and by using mouse models of ASD. Mouse models are an invaluable tool to get insights into the molecular and cellular counterparts of the disease, acting on the specific genetic background generating ASD-like phenotype. Given the multifaceted nature of ASD and related studies, it is often difficult to navigate the literature and limit the huge content to specific questions. This review fulfills the need for an organized, clear, and state-of-the-art perspective on cerebellar involvement in ASD, from its connections to the social brain areas (which are the primary sites of ASD impairments) to the use of monogenic mouse models.

MKK7, the essential regulator of JNK signaling involved in cancer cell survival: a newly emerging anticancer therapeutic target

One of the mitogen-activated protein kinases (MAPKs), c-Jun NH2-terminal protein kinase (JNK) plays an important role in regulating cell fate, such as proliferation, differentiation, development, transformation, and apoptosis. Its activity is induced through the interaction of MAPK kinase kinases (MAP3Ks), MAPK kinases (MAP2Ks), and various scaffolding proteins. Because of the importance of the JNK cascade to intracellular bioactivity, many studies have been conducted to reveal its precise intracellular functions and mechanisms, but its regulatory mechanisms remain elusive. In this review, we discuss the molecular characterization, activation process, and physiological functions of mitogen-activated protein kinase kinase 7 (MKK7), the MAP2K that most specifically controls the activity of JNK. Understanding the role of MKK7/JNK signaling in physiological conditions could spark new hypotheses for targeted anticancer therapies.

JIP3 localises to exocytic vesicles and focal adhesions in the growth cones of differentiated PC12 cells

The JNK-interacting protein 3 (JIP3) is a molecular scaffold, expressed predominantly in neurons, that serves to coordinate the activation of the c-Jun N-terminal kinase (JNK) by binding to JNK and the upstream kinases involved in its activation. The JNK pathway is involved in the regulation of many cellular processes including the control of cell survival, cell death and differentiation. JIP3 also associates with microtubule motor proteins such as kinesin and dynein and is likely an adapter protein involved in the tethering of vesicular cargoes to the motors involved in axonal transport in neurons. We have used immunofluorescence microscopy and biochemical fractionation to investigate the subcellular distribution of JIP3 in relation to JNK and to vesicular and organelle markers in rat pheochromocytoma cells (PC12) differentiating in response to nerve growth factor. In differentiated PC12 cells, JIP3 was seen to accumulate in growth cones at the tips of developing neurites where it co-localised with both JNK and the JNK substrate paxillin. Cellular fractionation of PC12 cells showed that JIP3 was associated with a subpopulation of vesicles in the microsomal fraction, distinct from synaptic vesicles, likely to be an anterograde-directed exocytic vesicle pool. In differentiated PC12 cells, JIP3 did not appear to associate with retrograde endosomal vesicles thought to be involved in signalling axonal injury. Together, these observations indicate that JIP3 may be involved in transporting vesicular cargoes to the growth cones of PC12 cells, possibly targeting JNK to its substrate paxillin, and thus facilitating neurite outgrowth.

Plasmodium falciparum evades mosquito immunity by disrupting JNK-mediated apoptosis of invaded midgut cells

The malaria parasite, Plasmodium, must survive and develop in the mosquito vector to be successfully transmitted to a new host. The Plasmodium falciparum Pfs47 gene is critical for malaria transmission. Parasites that express Pfs47 (NF54 WT) evade mosquito immunity and survive, whereas Pfs47 knockouts (KO) are efficiently eliminated by the complement-like system. Two alternative approaches were used to investigate the mechanism of action of Pfs47 on immune evasion. First, we examined whether Pfs47 affected signal transduction pathways mediating mosquito immune responses, and show that the Jun-N-terminal kinase (JNK) pathway is a key mediator of Anopheles gambiae antiplasmodial responses to P. falciparum infection and that Pfs47 disrupts JNK signaling. Second, we used microarrays to compare the global transcriptional responses of A. gambiae midguts to infection with WT and KO parasites. The presence of Pfs47 results in broad and profound changes in gene expression in response to infection that are already evident 12 h postfeeding, but become most prominent at 26 h postfeeding, the time when ookinetes invade the mosquito midgut. Silencing of 15 differentially expressed candidate genes identified caspase-S2 as a key effector of Plasmodium elimination in parasites lacking Pfs47. We provide experimental evidence that JNK pathway regulates activation of caspases in Plasmodium-invaded midgut cells, and that caspase activation is required to trigger midgut epithelial nitration. Pfs47 alters the cell death pathway of invaded midgut cells by disrupting JNK signaling and prevents the activation of several caspases, resulting in an ineffective nitration response that makes the parasite undetectable by the mosquito complement-like system.

The WAVE regulatory complex links diverse receptors to the actin cytoskeleton

The WAVE regulatory complex (WRC) controls actin cytoskeletal dynamics throughout the cell by stimulating the actin-nucleating activity of the Arp2/3 complex at distinct membrane sites. However, the factors that recruit the WRC to specific locations remain poorly understood. Here, we have identified a large family of potential WRC ligands, consisting of ∼120 diverse membrane proteins, including protocadherins, ROBOs, netrin receptors, neuroligins, GPCRs, and channels. Structural, biochemical, and cellular studies reveal that a sequence motif that defines these ligands binds to a highly conserved interaction surface of the WRC formed by the Sra and Abi subunits. Mutating this binding surface in flies resulted in defects in actin cytoskeletal organization and egg morphology during oogenesis, leading to female sterility. Our findings directly link diverse membrane proteins to the WRC and actin cytoskeleton and have broad physiological and pathological ramifications in metazoans.

Disassembly of the JIP1/JNK molecular scaffold by caspase-3-mediated cleavage of JIP1 during apoptosis

We report here the cleavage of the c-Jun N-terminal Kinase (JNK) pathway scaffold protein, JNK Interacting Protein-1 (JIP1), by caspases during both Tumour Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) and staurosporine-induced apoptosis in HeLa cells. During the initiation of apoptosis, maximal JNK activation is observed when JIP1 is intact, whereas cleavage of JIP1 correlates with JNK inactivation and progression of apoptosis. JIP1 is cleaved by caspase-3 at two sites, leading to disassembly of the JIP1/JNK complex. Inhibition of JIP1 cleavage by the caspase-3 inhibitor DEVD.fmk inhibits this disassembly, and is accompanied by sustained JNK activation. These data suggest that TRAIL and staurosporine induce JNK activation in a caspase-3-independent manner and that caspase-3-mediated JIP1 cleavage plays a role in JNK inactivation via scaffold disassembly during the execution phase of apoptosis. Caspase-mediated cleavage of JIP scaffold proteins may therefore represent an important mechanism for modulation of JNK signalling during apoptotic cell death.

The intense world theory - a unifying theory of the neurobiology of autism

Autism covers a wide spectrum of disorders for which there are many views, hypotheses and theories. Here we propose a unifying theory of autism, the Intense World Theory. The proposed neuropathology is hyper-functioning of local neural microcircuits, best characterized by hyper-reactivity and hyper-plasticity. Such hyper-functional microcircuits are speculated to become autonomous and memory trapped leading to the core cognitive consequences of hyper-perception, hyper-attention, hyper-memory and hyper-emotionality. The theory is centered on the neocortex and the amygdala, but could potentially be applied to all brain regions. The severity on each axis depends on the severity of the molecular syndrome expressed in different brain regions, which could uniquely shape the repertoire of symptoms of an autistic child. The progression of the disorder is proposed to be driven by overly strong reactions to experiences that drive the brain to a hyper-preference and overly selective state, which becomes more extreme with each new experience and may be particularly accelerated by emotionally charged experiences and trauma. This may lead to obsessively detailed information processing of fragments of the world and an involuntarily and systematic decoupling of the autist from what becomes a painfully intense world. The autistic is proposed to become trapped in a limited, but highly secure internal world with minimal extremes and surprises. We present the key studies that support this theory of autism, show how this theory can better explain past findings, and how it could resolve apparently conflicting data and interpretations. The theory also makes further predictions from the molecular to the behavioral levels, provides a treatment strategy and presents its own falsifying hypothesis.

Behavioral and cerebellar transmission deficits in mice lacking the autism-linked gene islet brain-2

Deletion of the human SHANK3 gene near the terminus of chromosome 22q is associated with Phelan-McDermid syndrome and autism spectrum disorders. Nearly all such deletions also span the tightly linked IB2 gene. We show here that IB2 protein is broadly expressed in the brain and is highly enriched within postsynaptic densities. Experimental disruption of the IB2 gene in mice reduces AMPA and enhances NMDA receptor-mediated glutamatergic transmission in cerebellum, changes the morphology of Purkinje cell dendritic arbors, and induces motor and cognitive deficits suggesting an autism phenotype. These findings support a role for human IB2 mutation as a contributing genetic factor in Chr22qter-associated cognitive disorders.

Ductal injection of JNK inhibitors before pancreas preservation prevents islet apoptosis and improves islet graft function

Human islet isolation to obtain high-quality islets is still challenging. This study investigates how c-Jun NH2- terminal kinase (JNK ) is activated during human and porcine islet isolation. We also investigated whether ductal injection of preservation solution with JNK inhibitors improves islet isolation results by preventing apoptosis of islet cells. A low molecular weight inhibitor (SP600125) and a cell-permeable peptide inhibitor, the latter introduced by protein transduction technology, were used in porcine and human studies, respectively. JNK activity progressively increased during the isolation procedure. The addition of 10 microM JNK inhibitors into the ductal preservation solution prevented JNK activation during the isolation procedure and prevented islet apoptosis immediately after isolation. We incubated islets (2000 islet equivalents) for 24-48 hr and then transplanted them below the kidney capsule of streptozotocin-induced diabetic mice. The blood glucose levels reached normoglycemia in more than 80% of the JNK inhibitor-positive group, whereas less than 20% of the JNK inhibitor-negative group achieved normoglycemia. These findings suggest that the JNK pathway is the major mediator of islet deterioration during/immediately after isolation and that JNK inhibition before islet isolation could improve outcomes after pancreatic islet transplantation.

Increased sinusoidal flow is not the primary stimulus to liver regeneration

BACKGROUND

Hemodynamic changes in the liver remnant following partial hepatectomy (PHx) have been suggested to be a primary stimulus in triggering liver regeneration. We hypothesized that it is the increased sinusoidal flow per se and hence the shear-stress stimulus on the endothelial surface within the liver remnant which is the main stimulus to regeneration. In order to test this hypothesis we wanted to increase the sinusoidal flow without performing a concomitant liver resection. Accordingly, we constructed an aorto-portal shunt to the left portal vein branch creating a standardized four-fold increase in flow to segments II, III and IV. The impact of this manipulation was studied in both an acute model (6 animals, 9 hours) using a global porcine cDNA microarray chip and in a chronic model observing weight and histological changes (7 animals, 3 weeks).

RESULTS

Gene expression profiling from the shunted segments does not suggest that increased sinusoidal flow per se results in activation of genes promoting mitosis. Hyperperfusion over three weeks results in the whole liver gaining a supranormal weight of 3.9% of the total body weight (versus the normal 2.5%). Contrary to our hypothesis, the weight gain was observed on the non-shunted side without an increase in sinusoidal flow.

CONCLUSIONS

An isolated increase in sinusoidal flow does not have the same genetic, microscopic or macroscopic impact on the liver as that seen in the liver remnant after partial hepatectomy, indicating that increased sinusoidal flow may not be a sufficient stimulus in itself for the initiation of liver regeneration.

Increased sinusoidal flow is not the primary stimulus to liver regeneration

BACKGROUND

Hemodynamic changes in the liver remnant following partial hepatectomy (PHx) have been suggested to be a primary stimulus in triggering liver regeneration. We hypothesized that it is the increased sinusoidal flow per se and hence the shear-stress stimulus on the endothelial surface within the liver remnant which is the main stimulus to regeneration. In order to test this hypothesis we wanted to increase the sinusoidal flow without performing a concomitant liver resection. Accordingly, we constructed an aorto-portal shunt to the left portal vein branch creating a standardized four-fold increase in flow to segments II, III and IV. The impact of this manipulation was studied in both an acute model (6 animals, 9 hours) using a global porcine cDNA microarray chip and in a chronic model observing weight and histological changes (7 animals, 3 weeks).

RESULTS

Gene expression profiling from the shunted segments does not suggest that increased sinusoidal flow per se results in activation of genes promoting mitosis. Hyperperfusion over three weeks results in the whole liver gaining a supranormal weight of 3.9% of the total body weight (versus the normal 2.5%). Contrary to our hypothesis, the weight gain was observed on the non-shunted side without an increase in sinusoidal flow.

CONCLUSIONS

An isolated increase in sinusoidal flow does not have the same genetic, microscopic or macroscopic impact on the liver as that seen in the liver remnant after partial hepatectomy, indicating that increased sinusoidal flow may not be a sufficient stimulus in itself for the initiation of liver regeneration.

The role of scaffold proteins in JNK signalling

This paper summarises how scaffold proteins affects and regulate the JNK signalling pathway. We believe that some of these scaffold proteins, by virtue of their anchoring and catalytic properties contribute to a high degree of specificity of intra cellular signalling pathways that regulate the progression through the cell cycle.

JNK3 is abundant in insulin-secreting cells and protects against cytokine-induced apoptosis

AIMS/HYPOTHESIS

In insulin-secreting cells, activation of the c-Jun NH(2)-terminal kinase (JNK) pathway triggers apoptosis. Whereas JNK1 and JNK2 are ubiquitously produced, JNK3 has been described exclusively in neurons. This report aims to characterise the expression and role in apoptosis of the three JNK isoforms in insulin-secreting cells exposed to cytokines.

METHODS

Sections of human and mouse pancreases were used for immunohistochemistry studies with isoform-specific anti-JNK antibodies. Human, pig, mouse and rat pancreatic islets were isolated by enzymatic digestion and RNA or protein extracts were prepared. RNA and protein levels were determined by quantitative RT-PCR and western blotting respectively, using JNK-isoform-specific primers and isoform-specific antibodies; activities of the three JNK isoforms were determined by kinase assays following quantitative immunoprecipitation/depletion of JNK3. JNK silencing was performed with small interfering RNAs and apoptotic rates were determined in INS-1E cells by scoring cells displaying pycnotic nuclei.

RESULTS

JNK3 and JNK2 mRNAs are the predominant isoforms expressed in human pancreatic islets. JNK3 is nuclear while JNK2 is also cytoplasmic. In INS-1E cells, JNK3 knockdown increases c-Jun levels and caspase-3 cleavage and sensitises cells to cytokine-induced apoptosis; in contrast, JNK1 or JNK2 knockdown is protective.

CONCLUSIONS/INTERPRETATION

In insulin-secreting cells, JNK3 plays an active role in preserving pancreatic beta cell mass from cytokine attacks. The specific localisation of JNK3 in the nucleus, its recruitment by cytokines, and its effects on key transcription factors such as c-Jun, indicate that JNK3 is certainly an important player in the transcriptional control of genes expressed in insulin-secreting cells.

Involvement of intracellular expression of FGF12 in radiation-induced apoptosis in mast cells

Several fibroblast growth factors (FGFs) are able to reduce and improve radiation-induced tissue damage through the activation of surface fibroblast growth factor receptors (FGFRs). In contrast, some FGFs lack classical signal sequences, which play roles in the release of FGFs, and the intracellular function of these FGFs is not well clarified. In this study, we evaluated the transcript levels of 22 FGFs in a human mast cell line, HMC-1, using quantitative RT-PCR and found that FGF2 and FGF12 were expressed in HMC-1 cells. FGF12 not only lacks classical signal sequences but also fails to activate FGFRs. HMC-1 cells were transfected with an expression vector of FGF12 to clarify the intracellular function of FGF12 after irradiation. The overexpression of FGF12 in HMC-1 cells decreased ionizing radiation-induced apoptosis, and siRNA-mediated repression of FGF12 expression augmented apoptosis in HMC-1 cells. The overexpression of FGF12 strongly suppressed the marked augmentation of apoptosis induced by inhibition of the MEK/ERK pathway with PD98059. In contrast, the mitogen-activated protein kinase (MAPK) scaffold protein islet brain 2 (IB2), which was reported to bind to FGF12, did not interfere with the anti-apoptotic effect of FGF12. The expression of FGF12 transcripts was also detected in murine cultured mast cells derived from bone marrow or fetal skin. These findings suggest that FGF12 intracellularly suppresses radiation-induced apoptosis in mast cells independently of IB2.

Regenerative response in the pig liver remnant varies with the degree of resection and rise in portal pressure

After parenchymal loss, the liver regenerates restoring normal mass and metabolic function. Prevailing theories on triggering events leading to regeneration include humoral, metabolic, and flow-mediated mechanisms, the latter emphasizing the importance of shear stress mediated nitric oxide regulation. We aimed to investigate whether the grade of resection and hence the portal venous pressure and sinusoidal shear stress increase would be reflected in the gene expression profiles in the liver remnant by using a global porcine cDNA microarray chip with approximately 23,000 genes represented. Six pig livers were resected with 62% (low portal pressure resection) and 75% (high portal pressure resection), resulting in a portal venous pressure increase from a baseline of 6.1-8.2 and 12 mmHg, respectively. By sampling consecutive biopsies from the liver remnants, we found differentially expressed genes in the high portal pressure resection group to have functions related primarily to apoptosis, nitric oxide metabolism and oxidative stress, whereas differentially expressed genes in the low portal pressure resection group potentially regulate the cell cycle. Common to both groups was the upregulation of genes regulating inflammation, transport, cell proliferation, development, and protein metabolism. Also common to both groups was both up- and downregulation of genes regulating cell-cell signaling, signal transduction, cell adhesion, and translation. Genes regulating the metabolism of lipids, hormones, amines, and alcohol were downregulated in both groups. In conclusion, the genetic regenerative response in the liver remnant to varies according to the level of resection.

Scaffold proteins of MAP-kinase modules

Mitogen-activated protein kinases (MAPKs) regulate critical signaling pathways involved in cell proliferation, differentiation and apoptosis. Recent studies have shown that a novel class of scaffold proteins mediates the structural and functional organization of the three-tier MAPK module. By linking the MAP3K, MAP2K and MAPK into a multienzyme complex, these MAPK-specific scaffold proteins provide an insulated physical conduit through which signals from the respective MAPK can be transmitted to the appropriate spatiotemporal cellular loci. Scaffold proteins play a determinant role in modulating the signaling strength of their cognate MAPK module by regulating the signal amplitude and duration. The scaffold proteins themselves are finely regulated resulting in dynamic intra- and inter-molecular interactions that can modulate the signaling outputs of MAPK modules. This review focuses on defining the diverse mechanisms by which these scaffold proteins interact with their respective MAPK modules and the role of such interactions in the spatiotemporal organization as well as context-specific signaling of the different MAPK modules.

Activation of c-Jun NH2-terminal kinase during islet isolation

Pancreatic islet transplantation has been remarkably improved by the Edmonton protocol; however, it is not easy to achieve insulin independence after islet transplantation from one donor pancreas. The islet isolation procedure itself destroys cellular and noncellular components of the pancreas that probably play a role in supporting islet survival. Further islet transplantation exposes cells to a variety of stressful stimuli such as proinflammatory cytokines. The reduction in islet mass immediately after isolation and transplantation implicates beta cell death by apoptosis and the prerecruitment of intracellular death signalling pathways. The c-Jun NH2-terminal kinases (JNKs) are classic stress-activated protein kinases and many cellular stresses have been shown to stimulate JNK activation. JNK in the pancreas is activated during brain death, pancreas procurement, and organ preservation, and its activity is progressively increased during the isolation procedure. Moreover, JNK activity in the transplanted liver after islet transplantation increases markedly within 24 hrs. Use of the JNK inhibitor in pancreas preservation, islet culture, and/or islet transplantation prevents islet apoptosis and improves islet graft function. These findings suggest that the control of JNK activation is important for pancreatic islet transplantation.

Activation of c-Jun NH2-terminal kinase (JNK) pathway during islet transplantation and prevention of islet graft loss by intraportal injection of JNK inhibitor

AIMS/HYPOTHESIS

Although application of the Edmonton protocol has markedly improved the outcome for pancreatic islet transplantation, the insulin independence rate after islet transplantation from one donor pancreas has remained low. During the isolation process and subsequent clinical transplantation, islets are subjected to severe adverse conditions that impair survival and ultimately contribute to graft failure. The aim of this study was to map the c-Jun NH2-terminal kinase (JNK) pathway that mediates islet loss during islet transplantation and to clarify whether intraportal injection with JNK inhibitor during islet transplantation can prevent islet graft loss.

METHODS

We measured JNK activity in the liver, fat and muscle of diabetic mice and in the liver immediately after islet transplantation. We examined the effect of intraportal injection of JNK inhibitory peptide at islet transplantation.

RESULTS

JNK activity became progressively higher at least until 24 h after transplantation. The cell-permeable peptide of JNK inhibitor was delivered not only in the liver but also in other insulin target organs, preventing JNK activation in the liver at least until 24 h after transplantation and reducing JNK activity in these insulin target organs. Moreover, the peptide inhibitor prevented islet graft loss immediately after transplantation and improved islet transplant outcome.

CONCLUSIONS/INTERPRETATION

These findings suggest that control of the JNK pathway is extremely important in islet transplantation and that intraportal injection of JNK inhibitor during islet transplantation (addition of JNK inhibitor to transplant media) could prevent the impairment of islet cells, leading to improved outcome for pancreatic islet transplantation.

Similarities and differences between the Wnt and reelin pathways in the forming brain

One of the key features in development is the reutilization of successful signaling pathways. Here, we emphasize the involvement of the Wnt pathway, one of the five kinds of signal transduction pathway predominating early embryonic development of all animals, in regulating the formation of brain structure. We discuss the interrelationships between the Wnt and reelin pathways in the regulation of cortical layering. We summarize data emphasizing key molecules, which, when mutated, result in abnormal brain development. This integrated view, which is based on conservation of pathways, reveals the relative position of participants in the pathway, points to control mechanisms, and allows raising testable working hypotheses. Nevertheless, although signaling pathways are highly conserved from flies to humans, the overall morphology is not. We propose that future studies directed at understanding of diversification will provide fruitful insights on mammalian brain formation.

Salvage of ischemic myocardium: a focus on JNK

Myocardial infarction is a problem of utmost clinical significance, associated with an important morbidity and mortality. Actual treatment of this affection is focusing on the reperfusion of the occluded coronary-artery. A complementary approach would be to prevent the death of the ischemic myocardium by interacting with detrimental intracellular pathways. Several strategies have been successfully used to reduce the size of myocardial infarction in animal models. In this article, we will focus on the c-Jun N-terminal kinase (JNK), a member of the mitogen-activated (MAPK) protein kinase family and an important determinant of cell survival/death. We will review the role of JNK in cardiac ischemia/reperfusion and summarize recent advances in the use of JNK inhibitors to protect the myocardium.

Blocking Stress Signaling Pathways with Cell Permeable Peptides

Cells are continuously adapting to changes in their environment by activating extracellular stimuli-dependent signal transduction cascades. These cascades, or signaling pathways, culminate both in changes in genes expression and in the functional regulation of pre-existing proteins. The Mitogen-Activated Protein Kinases (MAPKs) constitute a structurally related class of signaling proteins whose distinctive feature is their ability to directly phosphorylate, and thereby modulate, the activity of the transcription factors that are targets of the initial stimuli. The specificity of activation of MAPK signaling modules is determined, at least for an important part, by the specificity of the protein-protein contacts that are required for the propagation of the signal. We will discuss how we may interfere with MAPK signaling by using short cell-permeable peptides able to block, through a competitive mechanisms, relevant protein-protein contacts, and their effects on signaling and cell function.

Ethanol rapidly causes activation of JNK associated with ER stress under inhibition of ADH

Acute ethanol loading causes oxidative stress to activate cell-death signaling via c-Jun NH2-terminal kinase (JNK) in livers. JNK are stimulated under conditions of endoplasmic reticulum (ER) stress which causes programmed cell death. However, no remarked cell death was observed in acute ethanol intoxication. Akt, one of the cell survival protein kinases, may be activated under ethanol loading. The aim of this study was to estimate activation of JNK and ER stress, role of ethanol metabolism on the activation, and association of JNK with Akt under acute ethanol loading using the perfused rat liver system. Activation of JNK or Akt and association of JNK and Akt with JNK interacting protein 1 were estimated by immunoprecipitation and immunoblotting. Expression of 78 kDa glucose-regulated protein (GRP78) mRNA, a biomarker of ER stress, was detected by quantitative real-time RT-PCR. Activations of JNK and Akt were enhanced by co-treatment with ethanol and a classical inhibitor of alcohol dehydrogenase (ADH). Addition of an antioxidant reduced the activation of JNK. Ethanol loading with ADH inhibition causes down-regulation of GRP78 mRNA levels. Therefore, these findings suggest first revelation that inhibition of ethanol metabolism complicates oxidative and ER stresses produced by ethanol.

Cell permeable peptide of JNK inhibitor prevents islet apoptosis immediately after isolation and improves islet graft function

Although application of the Edmonton protocol has markedly improved outcomes for pancreatic islet transplantation, the insulin independence rate after islet transplantation from one donor pancreas has proven to remain low. During the isolation process and subsequent clinical transplantation, islets are subjected to severe adverse conditions that impair survival and ultimately contribute to graft failure. Pancreas preservation with the two-layer method (TLM) has proven to improve transplant results by protecting isolated islets against apoptosis through the mitochondrial pathway. However, pancreas storage with TLM cannot protect against activation of c-Jun NH2-terminal kinase (JNK) in isolated islets. This study investigated whether delivery of a JNK inhibitory peptide (JNKI) via the protein transduction system can prevent apoptosis of islet cells immediately after isolation. For efficient delivery of the (JNKI into isolated islets, we synthesized JNKI as a C-terminal fusion peptide with the 11-arginine protein transduction domain (11R-JNKI). 11R efficiently delivered the JNKI into isolated islets and 11R-JNKI prevented islet apoptosis immediately after isolation and improved islet graft function. These findings suggest that peptide drugs could be useful for the prevention of the impairment of islet cells and lead to improvement in the outcomes for pancreatic islet transplantation.

JIP1 regulates neuronal apoptosis in response to stress

We examined if the relative expression of JNK-interacting protein 1 (JIP1) and phosphorylated c-Jun N-terminal kinase (JNK) regulates cell signaling and contributes to selective neuronal vulnerability in response to environmental stress. In clonal neuroblastoma cultures, stresses such as hypoxia, ischemia, Abeta peptides, and UV irradiation rapidly reduced JIP1 expression. JIP1 mRNA expression was also down-regulated by UV stress and was accompanied by increased JNK and c-Jun activation and cell death. JIP1 protein reduction was partially reversed both by inhibitors predominantly of caspase 3 and of the JNK pathway and resulted in significantly increased cell survival. Conversely, overexpression of JIP1 decreased both nuclear translocation of activated-JNK, and c-Jun phosphorylation induced by either UV irradiation, or the JNK upstream activators, MKK7 or MEKK1. Cell death was reduced about 50% compared to GFP-transfected controls. JIP1 overexpression did not facilitate either JNK expression or activation. In the normal, non-stressed human hippocampus and rat hippocampal organotypic cultures, JIP1 and JNK3 were inversely expressed with more JIP1 in CA2 and CA3 and less in CA1 neurons. In the human hippocampus, transient hypoxia/ischemia selectively spares neurons in CA2 and CA3 and induces death of neurons in the hippocampal CA1 subregion. In the cultures, ischemia reduced JIP1 expression and activated JNK, c-Jun, and caspase 3. Inhibitors of the JNK pathway, JNK activation directly and of caspase 3 activation each partially reversed these effects. Thus, under certain stress conditions, down-regulation of JIP1 expression makes neurons more susceptible to apoptosis, suggesting JIP may serve as an anti-apoptosis factor.

From JNK to Pay Dirt: Jun Kinases, their Biochemistry, Physiology and Clinical Importance

The c-Jun N-terminal kinases (JNKs) were originally identified by their ability to phosphorylate c-Jun in response to UV-irradiation, but now are recognized as critical regulators of various aspects of mammalian physiology, including: cell proliferation, cell survival, cell death, DNA repair and metabolism. JNK-mediated phosphorylation enhances the ability of c-Jun, a component of the AP-1 transcription factor, to activate transcription, in response to a plethora of extracellular stimuli. The JNK activation leads to induction of AP-1-dependent target genes involved in cell proliferation, cell death, inflammation, and DNA repair. The JNKs, which are encoded by three different Jnk loci, are now known to be regulated by many other stimuli, from pro-inflammatory cytokines to obesity, in addition to UV-irradiation. Targeted disruption of the Jnk loci in mice has proved to be a critical tool in better understanding their physiological functions. Such studies revealed that the JNKs play important roles in numerous cellular processes, including: programmed cell death, T cell differentiation, negative regulation of insulin signaling, control of fat deposition, and epithelial sheet migration. Importantly, the JNKs have become prime targets for drug development in several important clinical areas, including: inflammation, diabetes, and cancer.

The level of TACI gene expression in myeloma cells is associated with a signature of microenvironment dependence versus a plasmablastic signature

B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) have been shown to promote multiple myeloma (MM) cell growth. We show that the main site of production for BAFF and APRIL is the bone marrow (BM) environment, and that production is mainly by monocytes and neutrophils. In addition, osteoclasts produce very high levels of APRIL, unlike BM stromal cells. Myeloma cells (MMCs) express TACI (transmembrane activator and calcium modulator and cyclophilin ligand interactor), the receptor of BAFF/APRIL, at varying levels. TACI expression is a good indicator of a BAFF-binding receptor. Expression data of purified MMCs from 65 newly diagnosed patients have been generated using Affymetrix microarrays and were analyzed by supervised clustering of groups with higher (TACI(hi)) versus lower (TACI(lo)) TACI expression levels. Patients in the TACI(lo) group had clinical parameters associated with bad prognosis. A set of 659 genes was differentially expressed between TACI(hi) and TACI(lo) MMCs. This set makes it possible to efficiently classify TACI(hi) and TACI(lo) MMCs in an independent cohort of 40 patients. TACI(hi) MMCs displayed a mature plasma cell gene signature, indicating dependence on the BM environment. In contrast, the TACI(lo) group had a gene signature of plasmablasts, suggesting an attenuated dependence on the BM environment. Taken together, our findings suggest using gene expression profiling to identify the group of patients who might benefit most from treatment with BAFF/APRIL inhibitors.

Fibroblast growth factor homologous factors: evolution, structure, and function

Fibroblast growth factor homologous factors (FHFs) bear strong sequence and structural similarity to fibroblast growth factors (FGFs). However, the biochemical and functional properties of FHFs are largely, if not totally, unrelated to those of FGFs. Whereas FGFs function through binding to the extracellular domains of FGF receptors (FGFRs), FHFs bind to intracellular domains of voltage-gated sodium channels (VGSCs) and to a neuronal MAP kinase scaffold protein, islet-brain-2 (IB2). These findings demonstrate the remarkable functional adaptability during evolution of the FGF gene family. FHF gene mutations in mice result in a range of neurological abnormalities, and at least one of these anomalies, cerebellar ataxia, is linked to FHF mutations in humans. This article reviews the sequences and structure of FHFs, along with our still limited understanding of FHF function.

Intracellular stress signaling pathways activated during human islet preparation and following acute cytokine exposure

Pancreatic islet transplantation may successfully restore normoglycemia in type 1 diabetic patients. However, successful grafting requires transplantation of a sufficient number of islets, usually requiring two or more donors. During the isolation process and following clinical transplantation, islets are subjected to severe adverse conditions that impair survival and ultimately contribute to graft failure. Here, we have mapped the major intracellular stress-signaling pathways that may mediate human islet loss during isolation and following cytokine attack. We found that the isolation procedure potently recruits two pathways consisting of |mitogen-activated protein kinase kinase (MKK)7 --> Jun NH(2)-terminal kinase (JNK)/p38 --> c-fos| and the |nuclear factor-kappaB (NF-kappaB) --> iNOS| module. Cytokines activate the |NF-kappaB --> iNOS| and |MKK4/MKK3/6 --> JNK/p38| pathways without recruitment of c-fos. Culturing the islets for 48 h after isolation allows for the activated pathways to return to background levels, with expression of MKK7 becoming undetectable. These data indicate that isolation and cytokines recruit different death pathways. Therefore, strategies might be rationally developed to avoid possible synergistic activation of these pathways in mediating islet loss during isolation and following grafting.

Regulation of MAP kinase signaling modules by scaffold proteins in mammals

The mitogen-activated protein kinase (MAPK) group of serine/threonine protein kinases mediates the response of cells to many extracellular stimuli such as cytokines and growth factors. These protein kinases include the extracellular signal-regulated protein kinases (ERK) and two stress-activated protein kinases (SAPK), the c-Jun N-terminal kinases (JNK), and the p38 MAPK. The enzymes are evolutionarily conserved and are activated by a common mechanism that involves a protein kinase cascade. Scaffold proteins have been proposed to interact with MAPK pathway components to create a functional signaling module and to control the specificity of signal transduction. Here we critically evaluate the evidence that supports a physiologically relevant role of MAPK scaffold proteins in mammals.

Calcium- and proteasome-dependent degradation of the JNK scaffold protein islet-brain 1

In models of type 1 diabetes, cytokines induce pancreatic beta-cell death by apoptosis. This process seems to be facilitated by a reduction in the amount of the islet-brain 1/JNK interacting protein 1 (IB1/JIP1), a JNK-scaffold with an anti-apoptotic effect. A point mutation S59N at the N terminus of the scaffold, which segregates in diabetic patients, has the functional consequence of sensitizing cells to apoptotic stimuli. Neither the mechanisms leading to IB1/JIP1 down-regulation by cytokines nor the mechanisms leading to the decreased capacity of the S59N mutation to protect cells from apoptosis are understood. Here, we show that IB1/JIP1 stability is modulated by intracellular calcium. The effect of calcium depends upon JNK activation, which primes the scaffold for ubiquitination-mediated degradation via the proteasome machinery. Furthermore, we observe that the S59N mutation decreases IB1/JIP1 stability by sensitizing IB1/JIP1 to calcium- and proteasome-dependent degradation. These data indicate that calcium influx initiated by cytokines mediates ubiquitination and degradation of IB1/JIP1 and may, therefore, provide a link between calcium influx and JNK-mediated apoptosis in pancreatic beta-cells.

The transmembrane domain and PXXP motifs of ApoE receptor 2 exclude it from carrying out clathrin-mediated endocytosis

The low density lipoprotein (LDL) receptor family comprises several proteins with similar structures including the LDL receptor and apoE receptor 2 (apoER2). The human brain expresses two major splice variants of apoER2 mRNA, one of which includes an additional exon that encodes 59 residues in the cytoplasmic domain. This exon is absent from the LDL receptor and contains three proline-rich (PXXP) motifs that may allow apoER2 to function as a signal transducer. To investigate the role of this insert, we took advantage of the well characterized low density lipoprotein receptor pathway. Chimeras comprising the ectodomain and transmembrane domain of the LDL receptor fused to the cytoplasmic domain of apoER2 lacking the PXXP-containing residues are able to mediate clathrin-dependent endocytosis of LDL as effectively as cells expressing the LDL receptor but not if the PXXP insert is present in the protein. Although expressed on the cell surface, the PXXP-containing chimeric receptor is excluded from clathrin vesicles as judged by its failure to co-localize with adaptor protein-2 possibly due to interaction with intracellular adaptors or scaffolding proteins. Chimeras with the transmembrane domain of apoER2, predicted to be longer than that of the LDL receptor by several residues, fail to mediate endocytosis of LDL or to co-localize with adaptor protein-2 regardless of the presence or absence of the PXXP insert. Thus features of apoER2 that distinguish it as a signaling receptor, rather than as an endocytosis receptor like the LDL receptor, reside in or near the transmembrane domain and in the proline-rich motifs.

Fibroblast growth factors as regulators of central nervous system development and function

Fibroblast growth factors (FGFs) are multifunctional signaling proteins that regulate developmental processes and adult physiology. Over the last few years, important progress has been made in understanding the function of FGFs in the embryonic and adult central nervous system. In this review, I will first discuss studies showing that FGF signaling is already required during formation of the neural plate. Next, I will describe how FGF signaling centers control growth and patterning of specific brain structures. Finally, I will focus on the function of FGF signaling in the adult brain and in regulating maintenance and repair of damaged neural tissues.

Fibroblast growth factor homologous factors and the islet brain-2 scaffold protein regulate activation of a stress-activated protein kinase

Fibroblast growth factor homologous factors (FHFs) form native intracellular complexes with the mitogen-activated protein kinase (MAPK) scaffold protein islet-brain 2 (IB2) in adult brain. FHF binding to IB2 facilitates recruitment of the MAPK p38delta (SAPK4), while failing to stimulate binding of JNK, the preferred kinase of the related scaffold IB1 (JIP-1). We now report further biochemical evidence supporting FHFs as regulators of IB2 scaffold activity. Mixed lineage kinase 3 (MLK3) and IB2 synergistically activate p38delta but not the MAPKs JNK-1 and p38alpha. Binding of p38delta to IB2 is mediated by the carboxyl-terminal half of the scaffold (IB2(Delta1-436)). FHF2 also binds weakly to IB2(Delta1-436) and can thereby increase p38delta interaction with IB2(Delta1-436). FHF-induced recruitment of p38delta to IB2 is accompanied by increased levels of activated p38delta, and synergistic activation of p38delta by MLK3 and IB2 is further enhanced by FHF2. Consistent with a role for FHFs as signaling molecules, FHF2 isolated from rat brain is serine/threonine-phosphorylated, and FHF can serve as a substrate for p38delta in vitro. These results support the existence of a signaling module in which IB2 scaffolds a MLK3/MKK/p38delta kinase cascade. FHFs aid in recruitment of p38 to IB2 and may serve as kinase substrates.

Phosphorylation-dependent scaffolding role of JSAP1/JIP3 in the ASK1-JNK signaling pathway. A new mode of regulation of the MAP kinase cascade

JSAP1 (also termed JIP3) is a scaffold protein that interacts with specific components of the JNK signaling pathway. Apoptosis signal-regulating kinase (ASK) 1 is a MAP kinase kinase kinase that activates the JNK and p38 mitogen-activated protein (MAP) kinase cascades in response to environmental stresses such as reactive oxygen species. Here we show that JSAP1 bound ASK1 and enhanced ASK1- and H(2)O(2)-induced JNK activity. ASK1 phosphorylated JSAP1 in vitro and in vivo, and the phosphorylation facilitated interactions of JSAP1 with SEK1/MKK4, MKK7 and JNK3. Furthermore, ASK1-dependent phosphorylation was required for JSAP1 to recruit and thereby activate JNK in response to H(2)O(2). We thus conclude that JSAP1 functions not only as a simple scaffold, but it dynamically participates in signal transduction by forming a phosphorylation-dependent signaling complex in the ASK1-JNK signaling module.

Akt1 regulates a JNK scaffold during excitotoxic apoptosis

Cell survival is determined by a balance among signaling cascades, including those that recruit the Akt and JNK pathways. Here we describe a novel interaction between Akt1 and JNK interacting protein 1 (JIP1), a JNK pathway scaffold. Direct association between Akt1 and JIP1 was observed in primary neurons. Neuronal exposure to an excitotoxic stimulus decreased the Akt1-JIP1 interaction and concomitantly increased association between JIP1 and JNK. Akt1 interaction with JIP1 inhibited JIP1-mediated potentiation of JNK activity by decreasing JIP1 binding to specific JNK pathway kinases. Consistent with this view, neurons from Akt1-deficient mice exhibited higher susceptibility to kainate than wild-type littermates. Overexpression of Akt1 mutants that bind JIP1 reduced excitotoxic apoptosis. These results suggest that Akt1 binding to JIP1 acts as a regulatory gate preventing JNK activation, which is released under conditions of excitotoxic injury.

Interaction of Rac exchange factors Tiam1 and Ras-GRF1 with a scaffold for the p38 mitogen-activated protein kinase cascade

Tiam1 and Ras-GRF1 are guanine nucleotide exchange factors (GEFs) that activate the Rac GTPase. The two GEFs have similar N-terminal regions containing pleckstrin homology domains followed by coiled-coils and additional sequences that function together to allow regulated GEF activity. Here we show that this N-terminal region of both proteins binds to the scaffold protein IB2/JIP2. IB2/JIP2 is a scaffold for the p38 mitogen-activated protein (MAP) kinase cascade because it binds to the Rac target MLK3, the MAP kinase kinase MKK3, and the p38 MAP kinase. Expression of IB2/JIP2 in cells potentiates the ability of Tiam1 or Ras-GRF1 to activate the p38 MAP kinase cascade but not the Jnk MAP kinase cascade. In addition, Tiam1 or Ras-GRF1 binding to IB2/JIP2 increases the association of the components of the p38 MAP kinase signaling cassette with IB2/JIP2 in cells and activates scaffold-associated p38. These findings imply that Tiam1 and Ras-GRF1 can contribute to Rac signaling specificity by their ability to form a complex with a scaffold that binds components of one of the many known Rac effector pathways.

Requirement of the JIP1 scaffold protein for stress-induced JNK activation

The c-Jun N-terminal kinase (JNK) signal transduction pathway is activated in response to the exposure of cells to environmental stress. Components of the JNK signaling pathway interact with the JIP1 scaffold protein. JIP1 is located in the neurites of primary hippocampal neurons. However, in response to stress, JIP1 accumulates in the soma together with activated JNK and phosphorylated c-Jun. Disruption of the Jip1 gene in mice by homologous recombination prevented JNK activation caused by exposure to excitotoxic stress and anoxic stress in vivo and in vitro. These data show that the JIP1 scaffold protein is a critical component of a MAP-kinase signal transduction pathway.

Fibroblast growth factor homologous factors are intracellular signaling proteins

Fibroblast growth factors (FGFs) mediate cell growth, differentiation, migration, and morphogenesis by binding to the extracellular domain of cell surface receptors, triggering receptor tyrosine phosphorylation and signal transduction [1-5]. FGF homologous factors (FHFs) were discovered within vertebrate DNA sequence databases by virtue of their sequence similarity to FGFs [3, 6, 7], but the mechanism of FHF action has not been reported. We show here that FHF-1 is associated with the MAP kinase (MAPK) scaffold protein Islet-Brain-2 (IB2) [8] in the brain and in specific cell lines. FHF/IB2 interaction is highly specific, as FHFs do not bind to the related scaffold protein IB1(JIP-1b) [9, 10], nor can FGF-1 bind to IB2. We further show that FHFs enable IB2 to recruit a specific MAPK in transfected cells, and our data suggest that the scaffolds IB1 and IB2 have different MAPK specificities. Hence, FHFs are intracellular components of a tissue-specific protein kinase signaling module.

Cell-permeable peptide inhibitors of JNK: novel blockers of beta-cell death

Stress conditions and proinflammatory cytokines activate the c-Jun NH2-terminal kinase (JNK), a member of the stress-activated group of mitogen-activated protein kinases (MAPKs). We recently demonstrated that inhibition of JNK signaling with the use of the islet-brain (IB) 1 and 2 proteins prevented interleukin (IL)-1beta-induced pancreatic beta-cell death. Bioactive cell-permeable peptide inhibitors of JNK were engineered by linking the minimal 20-amino acid inhibitory domains of the IB proteins to the 10-amino acid HIV-TAT sequence that rapidly translocates inside cells. Kinase assays indicate that the inhibitors block activation of the transcription factor c-Jun by JNK. Addition of the peptides to the insulin-secreting betaTC-3 cell line results in a marked inhibition of IL-1beta-induced c-jun and c-fos expression. The peptides protect betaTC-3 cells against apoptosis induced by IL-1beta. All-D retro-inverso peptides penetrate cells as efficiently as the L-enantiomers, decrease c-Jun activation by JNK, and remain highly stable inside cells. These latter peptides confer full protection against IL-1beta-induced apoptosis for up to 2 weeks of continual treatment with IL-1beta. These data establish these bioactive cell-permeable peptides as potent pharmacological compounds that decrease intracellular JNK signaling and confer long-term protection to pancreatic beta-cells from IL-1beta-induced apoptosis.

Massive parallel gene expression profiling of RINm5F pancreatic islet beta-cells stimulated with interleukin-1beta

Interleukin 1 (IL-1) is a pleiotropic cytokine with the potential to kill pancreatic beta-cells, and this unique property is thought to be involved in the pathogenesis of type I diabetes mellitus. We therefore determined the quantitative expression of 24,000 mRNAs of RINm5F, an insulinoma cell line derived from rat pancreatic beta-cells, before and after challenge with 30 and 1,000 pg/ml of recombinant human IL-1beta. The highest concentration resulted in decreased insulin production and cell death over a period of 4 days. Using three different time points, 2, 4 and 24 hours after challenge, we found that 146 full-length genes and a large number of expressed sequence tags were differentially regulated 3-fold or more. Most of the differentially regulated transcripts have not previously been described to be regulated by IL-1beta in beta-cells. We have analysed the expression data and sorted the genes into groups according to functional relations on the basis of knowledge of the structure or function ascribed to the individual genes. Many of the differentially regulated genes are known to play a role in immune- and stress-related pathways as well as in insulin secretion and vesicle trafficking, e.g. alpha-endosulfine and K+ channel Kir6.2 are differentially regulated. A number of transcripts in the biosynthesis pathway for cholesterol are also differentially regulated.