Evaluation of a Multimodal Stress Management and Comprehensive Lifestyle Modification Program on Quality of Life and Gastrointestinal Symptoms in Patients with Crohn's Disease: A Randomized Controlled Pilot Trial with 9-Month Follow-Up.

INTRODUCTION: Stress and lifestyle factors impact the course of Crohn's disease (CD). Our primary objective was to assess whether patients with CD benefit from a mind-body-medicine stress management and lifestyle modification (MBM) program. METHODS: This 9-month two-arm pilot trial was conducted in Bamberg, Germany (2020-2021). Patients (18-75 years) with mild to moderate activity of CD and stable medication were enrolled and randomly assigned to either a 10-week MBM program (intervention group, IG) or a single 90-min education session (waiting list control group, CG). Primary endpoints were quality of life (IBDQ) and disease activity (HBI). Secondary endpoints were emotional distress, core self-evaluation, and inflammatory biomarkers 3 and 9 months after baseline assessment. RESULTS: We analyzed data from 37 patients (IG: n = 19, mean ± SD age 49.6 ± 13.1 years, 68% female; CG: 18, 46.8 ± 11.4, 67% female). Immediately after the intervention, 79% (IG) and 44% (CG) experienced a clinically relevant improvement (IBDQ score ≥16 points). This was similar after 9 months (63% vs. 44%). There was no difference in disease activity (3 months: p = 0.082, 95% CI -1.3 to 2.6; 9 months: p = 0.251, 95% CI -1.2 to 2.5). Secondary outcomes indicated improvements in emotional distress, core self-evaluation, erythrocyte sedimentation rate after three and in emotional distress, T-cell profiling in the blood, and fecal lactoferrin and calprotectin group after 9 months in the IG. CONCLUSION: Our study suggested benefits of a multimodal stress management and lifestyle modification program for patients with CD. Larger trials are needed to determine if the program can supplement or at least partially replace pharmacological treatment approaches.

Pre-treatment expectations and their influence on subjective symptom change in Crohn's disease.

BACKGROUND: Treatment expectations reportedly shape treatment outcomes, but have not been studied in the context of multimodal therapy in Crohn's disease (CD). Therefore, the current study investigated the role of treatment expectations for subjective symptom changes in CD patients who have undergone an integrative multimodal therapy program. METHODS: Validated questionnaires were completed at the start of the treatment program and post intervention. Pre-treatment expectations and experienced symptom change were assessed with the Generic Rating Scale for Previous Treatment Experiences, Treatment Expectations, and Treatment Effects (GEEE); stress levels were quantified with the Perceived Stress Scale (PSS-10) and disease specific quality of life was quantified with the disease-specific Inflammatory Bowel Disease Questionnaire (IBDQ). We performed multiple linear and Bayesian regression to determine how expectations related to symptom change. RESULTS: N = 71 CD patients (66.2% female) were included. Stronger expectations regarding symptom improvement (b = 0.422, t = 3.70, p < .001) were associated with higher experienced symptom improvement. Additionally, Bayesian analysis provided strong evidence for including improvement expectations as a predictor of improvement experience (BFinclusion = 13.78). CONCLUSIONS: In line with research in other disorders, we found that positive treatment expectations were associated with experienced symptom improvement. In contrast, we found no indication that an experience of symptom worsening was associated with positive or negative baseline treatment expectations. Induction of positive expectations might be a potential avenue for improving treatment outcomes in CD therapy.

Systematic review with meta-analysis: Stress-management interventions for patients with irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder of unknown pathological origin that is associated with psychological distress and reduced health-related quality of life (HRQoL). We investigated the effects of stress-management for adults with IBS on typical symptoms, HRQoL and mental health. With predefined criteria (patients: adults with IBS; intervention: stress-management; control: care as usual or waitlist; outcome: patient-relevant; study-type: controlled trials), we registered the study with PROSPERO (168030) and searched the main medical databases. Two researchers independently reviewed the publications and assessed the risk of bias using the Scottish Intercollegiate Guidelines Network checklist. We performed meta-analysis with homogeneous trials of acceptable quality. After screening 6656 publications, ten suitable randomized trials of acceptable (n = 5) or low methodological quality (n = 5) involving 587 patients were identified. Our meta-analysis showed no effect of stress-management on IBS severity 1-2 months after the intervention (Hedges' g = -0.23, 95%-CI = -0.84 to -0.38, I2  = 86.1%), and after 3-12 months (Hedges' g = -0.77, 95%-CI = -1.77 to -0.23, I2  = 93.3%). One trial found a short-term reduction of symptoms, and one trial found symptom relief in the long-term (at 6 months). One of two studies that examined HRQoL found an improvement (after 2 months). One of two studies that examined depression and anxiety found a reduction of these symptoms (after 3 weeks). Stress-management may be beneficial for patients with IBS regarding the short-term reduction of bowel and mental health symptoms, whereas long-term benefits are unclear. Good quality RCTs with more than 6 months follow-up are needed.

Mind-body-medicine and comprehensive lifestyle-modification in patients with Crohn's disease-Feasibility of a randomized controlled trial under pandemic circumstances.

Introduction: Mind-body medicine (MBM) focuses on stress reduction and lifestyle changes. The primary objective of this pilot trial was to test study feasibility of a complex integrative MBM program for patients with Crohn's disease (CD), especially in rural regions, and under pandemic conditions. Methods: Patients were stratified and randomized to the intervention group (IG) or the control group (CG). The intervention included a weekly 6-h session for 10 weeks. The CG (waiting list) received an initial 90-min workshop and started the intervention 9 months later. The primary outcome for study feasibility was recruitment and retention rates, as well as reasons for drop-out. The trial took place in Bamberg, Germany (September 2020 to December 2021). Results: Totally 700 members of the German Crohn's and Colitis Organization-DCCV-were contacted. A total of 15% (102/700; 95% CI 12-17%) expressed interest to participate. Following screening, 41% (95% CI 32-50) were randomized to IG (n = 22) and CG (n = 20). The patients were on average (±standard deviation) 48 ± 13 years old, 67% were female, and have been suffering from CD for 20 ± 12 years. Patients traveled 71.5 ± 48.7 km (range: 9-227 km) to the intervention with no differences between IG and CG. At the 6-month follow-up, 36/42 (86%, 95% CI 74-95%) participants completed final assessment and 19/22 (86%, 95% CI 70-100%) the intervention. The most important reasons for non-responding were work-related (12/60; 20%) and for or drop-out pandemic-related anxiety (3/6). No patient and staff member became infected with SARS-CoV-2 during the study. Conclusion: The feasibility of the MBM study was confirmed in terms of predefined recruitment and retention criteria, both despite difficult conditions (including the rural setting) and patients' fears associated with the pandemic. It was crucial to develop appropriate hygiene and safety concepts that enable chronically ill patients to participate in helpful group-based interventions even under pandemic conditions. Clinical trial registration: ClinicalTrials.gov, identifier: NCT05182645.

Use of complementary and alternative medicine (CAM) in patients with inflammatory bowel disease (IBD): results from a German nationwide survey of 2019 compared to a previous survey of 2002.

INTRODUCTION: In 2002, 50% of patients with Inflammatory Bowel Disease (IBD) had used complementary and alternative medicine (CAM) in Germany. This survey aimed to examine changes from 2002 to 2019 and predictors of CAM use in 2019. MATERIALS AND METHODS: In 2019, a questionnaire was sent randomly to 1000 members of the German Crohn's Colitis Association, the same sampling strategy was chosen 2002. Items assessed included, demographic characteristics, IBD diagnosis and disease history, medication use, patients' symptoms/quality of life, anxiety/depression and use of complementary therapies. RESULTS: The 2019 sample only differed slightly in case of gender (55% women) and disease (43% Ulcerative Colitis) from the 2002 sample. In 2019, 54% (227/417) reported having ever used CAM and 75% (396/417) planned to use CAM for their IBD in the future, whereby there was an evidence of a decrease in exclusive CAM use from 2002 (28%; 96/344) to 2019 (16%, 37/277; BF<.01). In logistic regression analyses, ulcerative colitis compared to Crohn's Disease (OR 0.59, p=.005), side effects of standard therapy (OR 1.94, p=.012), the use of corticosteroids (OR 0.54, p=.038) or biologics (OR 1.90, p = .020) and lower quality of life (OR 0.96, p=.002) were associated with CAM use in 2019. CONCLUSIONS: Every other patient with IBD used CAM and has thus indicated a need for a safe and evidence-based combination of conventional and complementary approaches. This would further support the desired decrease in exclusive -alternative- CAM use.

Multimodal stress reduction and lifestyle modification program for patients with ulcerative colitis: a qualitative study.

BACKGROUND: Over 2 million people in Europe are affected by ulcerative colitis, which often severely impacts the quality of life of those concerned. Among other factors, lifestyle and psychosocial factors seem to play an important role in pathogenesis and course of the disease and can be addressed as a complement to pharmacotherapy in comprehensive lifestyle modification programs. METHODS: This qualitative study as part of a mixed methods approach was carried out in the framework of a randomized controlled trial that examined the effect of a comprehensive lifestyle-modification-program (10-week-day clinic program) on quality of life in patients with ulcerative colitis. Qualitative interviews were conducted with 20 out of 47 patients of the intervention group after the program. The aim was to deepen, supplement, and expand the quantitative results of the trial, i.e. to examine individual perceptions of the intervention, including subjective changes and the extent to which elements of the program were integrated into everyday life. Qualitative content analysis techniques utilizing the software MAXQDA were used. RESULTS: Patients with ulcerative colitis in our sample often experienced multiple negative effects on different levels (physical, psychological, and social) and impaired quality of life because of their disease. They reported generally positively about the program itself, and emphasized perceived positive changes regarding their psychological and physical well-being. The interviews indicated a good implementation of elements learned during the intervention in everyday life. CONCLUSIONS: Through participation in a comprehensive lifestyle modification program in the structure of a day clinic complementary to pharmacotherapy, patients with ulcerative colitis can reduce psychosocial stress and physical symptoms and thereby actively improve their well-being and general quality of life. This patient-centered, holistic approach was rated as useful in countering the complex disease manifestation as well as meeting the individual needs of the patients regarding their disease. TRIAL REGISTRATION: clinicaltrials.gov NCT02721823.

Cannabis use of patients with inflammatory bowel disease in Germany: a cross-sectional survey.

BACKGROUND AND AIMS: Progressive legalization and increasing utilization of medical cannabis open up potential new applications, including for inflammatory bowel disease (IBD). This study aimed to collect current figures on the use of and experience with cannabis among IBD patients in Germany. METHODS: A 71-item questionnaire was mailed to a randomly selected representative sample of 1000 IBD patients. RESULTS: Questionnaires were returned by 417 patients (mean age 49.1 ±â€Š17.0 years; 55.8 % women; 43.4 % ulcerative colitis and 54.7 % Crohn's disease). Seventy-three respondents (17.5 %) stated past cannabis use for recreational purposes, while 12 users mentioned usage at the time the questionnaire was completed (2.9 %). Seventeen patients (4.1 %) indicated past use of cannabis, and 18 participants (4.3 %) reported current use of cannabis to treat IBD. Perceived benefits of cannabis use by its users included reduced abdominal pain, improved sleep quality, and relief of unease and worry. They reported lower quality of life and higher levels of anxiety or depression than non-users. Of notice, 52.9 % of cannabis users obtained their cannabis from the black market. A total of 76.5 % of former and 50 % of current users did not report their cannabis use to the physician. CONCLUSION: This survey reveals the largest data set on cannabis use among IBD patients in Germany, with the potential for further research. Cannabis is mainly procured from the black market, with unknown quality.

Cryopreservation impairs 3-D migration and cytotoxicity of natural killer cells.

Natural killer (NK) cells are important effector cells in the immune response to cancer. Clinical trials on adoptively transferred NK cells in patients with solid tumors, however, have thus far been unsuccessful. As NK cells need to pass stringent safety evaluation tests before clinical use, the cells are cryopreserved to bridge the necessary evaluation time. Standard degranulation and chromium release cytotoxicity assays confirm the ability of cryopreserved NK cells to kill target cells. Here, we report that tumor cells embedded in a 3-dimensional collagen gel, however, are killed by cryopreserved NK cells at a 5.6-fold lower rate compared to fresh NK cells. This difference is mainly caused by a 6-fold decrease in the fraction of motile NK cells after cryopreservation. These findings may explain the persistent failure of NK cell therapy in patients with solid tumors and highlight the crucial role of a 3-D environment for testing NK cell function.

Downregulation of the microtubule associated protein tau impairs process outgrowth and myelin basic protein mRNA transport in oligodendrocytes.

Oligodendrocytes, the myelin forming cells of the CNS, are characterized by their numerous membranous extensions, which enwrap neuronal axons and form myelin sheaths. During differentiation oligodendrocytes pass different morphological stages, downregulate the expression of the proteoglycan NG2, and acquire major myelin specific proteins, such as myelin basic proteins (MBP) and proteolipid protein. MBP mRNA is transported in RNA granules along the microtubules (MTs) to the periphery and translated locally. MTs participate in the elaboration and stabilization of the myelin forming extensions and are essential for cellular sorting processes. Their dynamic properties are regulated by microtubule associated proteins (MAPs). The MAP tau is present in oligodendrocytes and involved in the regulation and stabilization of the MT network. To further elucidate the functional significance of tau in oligodendrocytes, we have downregulated tau by siRNA technology and studied the effects on cell differentiation and neuron-glia contact formation. The data show that tau knockdown impairs process outgrowth and leads to a decrease in MBP expression. Furthermore, MBP mRNA transport to distant cellular extensions is impaired and cells remain in the NG2 stage. In myelinating cocultures with dorsal root ganglion neurons, oligodendrocyte precursor cells after tau miR RNA lentiviral knockdown develop into NG2 positive cells with very long and thin processes, contacting axons loosely, but fail to form internodes. This demonstrates that tau is important for MBP mRNA transport and involved in process formation. The disturbance of the balance of tau leads to abnormalities in oligodendrocyte differentiation, neuron-glia contact formation and the early myelination process.

Oligodendroglial p130Cas is a target of Fyn kinase involved in process formation, cell migration and survival.

Oligodendrocytes are the myelinating glial cells of the central nervous system. In the course of brain development, oligodendrocyte precursor cells migrate, scan the environment and differentiate into mature oligodendrocytes with multiple cellular processes which recognize and ensheath neuronal axons. During differentiation, oligodendrocytes undergo dramatic morphological changes requiring cytoskeletal rearrangements which need to be tightly regulated. The non-receptor tyrosine kinase Fyn plays a central role in oligodendrocyte differentiation and myelination. In order to improve our understanding of the role of oligodendroglial Fyn kinase, we have identified Fyn targets in these cells. Purification and mass-spectrometric analysis of tyrosine-phosphorylated proteins in response to overexpressed active Fyn in the oligodendrocyte precursor cell line Oli-neu, yielded the adaptor molecule p130Cas. We analyzed the function of this Fyn target in oligodendroglial cells and observed that reduction of p130Cas levels by siRNA affects process outgrowth, the thickness of cellular processes and migration behavior of Oli-neu cells. Furthermore, long term p130Cas reduction results in decreased cell numbers as a result of increased apoptosis in cultured primary oligodendrocytes. Our data contribute to understanding the molecular events taking place during oligodendrocyte migration and morphological differentiation and have implications for myelin formation.

Moderate hypoxia followed by reoxygenation results in blood-brain barrier breakdown via oxidative stress-dependent tight-junction protein disruption.

Re-canalization of cerebral vessels in ischemic stroke is pivotal to rescue dysfunctional brain areas that are exposed to moderate hypoxia within the penumbra from irreversible cell death. Goal of the present study was to evaluate the effect of moderate hypoxia followed by reoxygenation (MHR) on the evolution of reactive oxygen species (ROS) and blood-brain barrier (BBB) integrity in brain endothelial cells (BEC). BBB integrity was assessed in BEC in vitro and in microvessels of the guinea pig whole brain in situ preparation. Probes were exposed to MHR (2 hours 67-70 mmHg O2, 3 hours reoxygenation, BEC) or towards occlusion of the arteria cerebri media (MCAO) with or without subsequent reperfusion in the whole brain preparation. In vitro BBB integrity was evaluated using trans-endothelial electrical resistance (TEER) and transwell permeability assays. ROS in BEC were evaluated using 2',7'-dichlorodihydrofluorescein diacetate (DCF), MitoSox and immunostaining for nitrotyrosine. Tight-junction protein (TJ) integrity in BEC, stainings for nitrotyrosine and FITC-albumin extravasation in the guinea pig brain preparation were assessed by confocal microscopy. Diphenyleneiodonium (DPI) was used to investigate NADPH oxidase dependent ROS evolution and its effect on BBB parameters in BEC. MHR impaired TJ proteins zonula occludens 1 (ZO-1) and claudin 5 (Cl5), decreased TEER, and significantly increased cytosolic ROS in BEC. These events were blocked by the NADPH oxidase inhibitor DPI. MCAO with or without subsequent reoxygenation resulted in extravasation of FITC-albumin and ROS generation in the penumbra region of the guinea pig brain preparation and confirmed BBB damage. BEC integrity may be impaired through ROS in MHR on the level of TJ and the BBB is also functionally impaired in moderate hypoxic conditions followed by reperfusion in a complex guinea pig brain preparation. These findings suggest that the BBB is susceptible towards MHR and that ROS play a key role in this process.

Making myelin basic protein -from mRNA transport to localized translation.

In the central nervous system (CNS) of most vertebrates, oligodendrocytes enwrap neuronal axons with extensions of their plasma membrane to form the myelin sheath. Several proteins are characteristically found in myelin of which myelin basic protein (MBP) is the second most abundant one after proteolipid protein. The lack of functional MBP in rodents results in a severe hypomyelinated phenotype in the CNS demonstrating its importance for myelin synthesis. Mbp mRNA is transported from the nucleus to the plasma membrane and is translated locally at the axon-glial contact site. Axonal properties such as diameter or electrical activity influence the degree of myelination. As oligodendrocytes can myelinate many axonal segments with varying properties, localized MBP translation represents an important part of a rapid and axon-tailored synthesis machinery. MBP's ability to compact cellular membranes may be problematic for the integrity of intracellular membranous organelles and can also explain why MBP is transported in oligodendrocytes in the form of an mRNA rather than as a protein. Here we review the recent findings regarding intracellular transport and signaling mechanisms leading to localized translation of Mbp mRNA in oligodendrocytes. More detailed insights into the MBP synthesis pathway are important for a better understanding of the myelination process and may foster the development of remyelination therapies for demyelinating diseases.

A thermoresponsive and chemically defined hydrogel for long-term culture of human embryonic stem cells.

Cultures of human embryonic stem cell typically rely on protein matrices or feeder cells to support attachment and growth, while mechanical, enzymatic or chemical cell dissociation methods are used for cellular passaging. However, these methods are ill defined, thus introducing variability into the system, and may damage cells. They also exert selective pressures favouring cell aneuploidy and loss of differentiation potential. Here we report the identification of a family of chemically defined thermoresponsive synthetic hydrogels based on 2-(diethylamino)ethyl acrylate, which support long-term human embryonic stem cell growth and pluripotency over a period of 2-6 months. The hydrogels permitted gentle, reagent-free cell passaging by virtue of transient modulation of the ambient temperature from 37 to 15 °C for 30 min. These chemically defined alternatives to currently used, undefined biological substrates represent a flexible and scalable approach for improving the definition, efficacy and safety of human embryonic stem cell culture systems for research, industrial and clinical applications.

Myelin basic protein synthesis is regulated by small non-coding RNA 715.

Oligodendroglial Myelin Basic Protein (MBP) synthesis is essential for myelin formation in the central nervous system. During oligodendrocyte differentiation, MBP mRNA is kept in a translationally silenced state while intracellularly transported, until neuron-derived signals initiate localized MBP translation. Here we identify the small non-coding RNA 715 (sncRNA715) as an inhibitor of MBP translation. SncRNA715 localizes to cytoplasmic granular structures and associates with MBP mRNA transport granule components. We also detect increased levels of sncRNA715 in demyelinated chronic human multiple sclerosis lesions, which contain MBP mRNA but lack MBP protein.

In vitro modeling of central nervous system myelination and remyelination.

This review aims to summarize the current techniques to study myelination and remyelination in culture systems. We attempt to put these into historical context, and to identify the strengths and weaknesses of each approach, which vary depending on the experimental question to be tested. We discuss the difficulty and importance of quantification of myelination and in particular remyelination. Finally, we provide our predictions of how these techniques will and should develop in the future.

Heterogeneous nuclear ribonucleoprotein (hnRNP) F is a novel component of oligodendroglial RNA transport granules contributing to regulation of myelin basic protein (MBP) synthesis.

Myelin basic protein (MBP) is a major component of central nervous system (CNS) myelin. The absence of MBP results in the loss of almost all compact myelin in the CNS. MBP mRNA is sorted into RNA granules that are transported to the periphery of oligodendrocytes in a translationally inactive state. A central mediator of this transport process is the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 that binds to the cis-acting A2-response element in the 3'UTR of MBP mRNA. Recently, we found that activation of the Src family nonreceptor tyrosine kinase Fyn in oligodendrocytes leads to phosphorylation of hnRNP A2 and to increased translation of MBP mRNA. Here, we identify the RNA-binding protein hnRNP F as a novel component of MBP mRNA transport granules. It is associated with hnRNP A2 and MBP mRNA in cytoplasmic granular structures and is involved in post-transcriptional regulation of MBP expression. Fyn kinase activity results in phosphorylation of hnRNP F in the cytoplasm and its release from MBP mRNA and RNA granules. Our results define hnRNP F as a regulatory element of MBP expression in oligodendrocytes and imply an important function of hnRNP F in the control of myelin synthesis.

Membrane lipid modification by polyunsaturated fatty acids sensitizes oligodendroglial OLN-93 cells against oxidative stress and promotes up-regulation of heme oxygenase-1 (HSP32).

Polyunsaturated fatty acids (PUFA) are highly abundant in brain tissue, and docosahexaenoic acid (DHA) might protect cells from oxidative stress (OS) during inflammation and demyelinating disorders, but also might exert pro-oxidant effects. Here we investigated if PUFA supplements lead to heat shock protein induction, altered cell survival properties and stress responses to OS exerted by hydrogen peroxide in oligodendroglial OLN-93 cells. The data show that supplements of various fatty acids (FA) with 18-22 carbons chain length and 2-6 double bonds led to PUFA enrichment in cellular membranes. Depending on the degree of desaturation, FA-supplements caused the up-regulation of heme oxygenase-1 (HSP32), a stress protein inducible by OS, and an increase in sensitivity to hydrogen peroxide-treatment. DHA, with the highest number of double bonds, was most effective. Co-treatment with DHA and the lipophilic vitamin E analogue alpha-tocopherol, suppressed heme oxygenase-1 up-regulation and cell survival was restored. Analysis of the lipid profile demonstrates that alpha-tocopherol not only has antioxidant capacities, but also directly modified the PUFA profile in cell membranes. Enrichment with higher omega-3, -6 and -9 PUFA and an increase in the biosynthesis rate of very long chain fatty acids, mainly changed the FA profile of ethanolamine and serine phosphoglycerides.

Physical forces in myelination and repair: a question of balance?

A recent report in BMC Cell Biology examines how the balance of extracellular forces and intracellular contractions regulate the shape changes required for oligodendrocyte myelination. A failure of remyelination such as seen in multiple sclerosis could be caused by loss of this balance.

Role of the oligodendroglial cytoskeleton in differentiation and myelination.

Oligodendrocytes, the myelin-forming cells of the central nervous system, are in culture characterized by an elaborate process network, terminating in flat membranous sheets that are rich in myelin-specific proteins and lipids, and spirally wrap axons forming a compact insulating layer in vivo. By analogy with other cell types, maintenance and stability of these processes, as well as the formation of the myelin sheath, likely rely on a pronounced cytoskeleton consisting of microtubules and microfilaments. While the specialized process of wrapping and compaction forming the myelin sheath is not well understood, considerably more is known about how cytoskeletal organization is mediated by extracellular and intracellular signals and other interaction partners during oligodendrocyte differentiation and myelination. Here, we review the current state of knowledge on the role of the oligodendrocyte cytoskeleton in differentiation with an emphasis on signal transduction mechanisms and will attempt to draw out implications for its significance in myelination.

The dynamic instability of microtubules is required for aggresome formation in oligodendroglial cells after proteolytic stress.

University of Oldenburg, Department of Biology, Molecular Neurobiology, D-26111 Oldenburg, Germany Ubiquitinated tau-positive inclusion bodies in oligodendrocytes are consistent features in a variety of neurodegenerative disorders, and their formation points to an underlying incapacity of the protein quality control system that normally prevents the accumulation of misfolded proteins. To study the consequences of proteasomal impairment, we have used an oligodendroglial cell line, namely OLN-t40 cells, genetically engineered to express the longest human tau isoform. Treatment of OLN-t40 cells with the proteasomal inhibitor MG-132 (0.5 microM, 18 h) caused the formation of large, nonfibrillary tau-positive aggregates containing the small HSP alphaB-crystallin and ubiquitin in the vicinity of the microtubule organizing center (MTOC). The sequestration of misfolded proteins into specialized regions, called aggresomes, in response to stress stimuli has been reported to be associated with a redistribution of intermediate filaments (IFs). In oligodendroglial cells, which do not contain a cytoplasmic IF system, aggresomelike inclusions were instead surrounded by bundles of MTs and contained clusters of mitochondria. Aggresome formation was prevented by both MT-stabilizing and -destabilizing drugs, indicating not only that an intact cytoskeleton but also the dynamic instability of the MT network is required. Furthermore, the binding of stress-induced alphaBcrystallin to the MTs points to a possible protective role during disease progression.