Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
79
result(s) for
"Knippschild, Uwe"
Sort by:
c-Jun N-terminal kinase 2 suppresses pancreatic cancer growth and invasion and is opposed by c-Jun N-terminal kinase 1
2022
The c-Jun N-terminal protein kinases (JNKs) JNK1 and JNK2 can act as either tumor suppressors or pro-oncogenic kinases in human cancers. The isoform-specific roles for JNK1 and JNK2 in human pancreatic cancer are still unclear, the question which should be addressed in this project. Human pancreatic cancer cell lines MIA PaCa-2 and PANC-1 clones were established either expressing either JNK1 or -2 shRNA in a stable manner. Basal anchorage-dependent and –independent cell growth, single-cell movement, and invasion using the Boyden chamber assay were analyzed. Xenograft growth was assessed using an orthotopic mouse model. All seven tested pancreatic cancer cell lines expressed JNKs as did human pancreatic cancer samples determined by immunohistochemistry. Pharmacological, unspecific JNK inhibition (SP600125) reduced cell growth of all cell lines but PANC-1. Especially inhibition of JNK2 resulted in overall increased oncogenic potential with increased proliferation and invasion, associated with alterations in cytoskeleton structure. Specific inhibition of JNK1 revealed opposing functions. Overall, JNK1 and JNK2 can exert different functions in human pancreatic cancer and act as counter players for tumor invasion. Specifically modulating the activity of JNKs may be of potential therapeutic interest in the future.
Journal Article
A MAFG-lncRNA axis links systemic nutrient abundance to hepatic glucose metabolism
by
Matteo Oliverio
,
Jan-Wilhelm Kornfeld
,
Jenny C. Link
in
38/91
,
631/208/4041/3196
,
631/337/2019
2020
Obesity and type 2 diabetes mellitus are global emergencies and long noncoding RNAs (lncRNAs) are regulatory transcripts with elusive functions in metabolism. Here we show that a high fraction of lncRNAs, but not protein-coding mRNAs, are repressed during diet-induced obesity (DIO) and refeeding, whilst nutrient deprivation induced lncRNAs in mouse liver. Similarly, lncRNAs are lost in diabetic humans. LncRNA promoter analyses, global cistrome and gain-of-function analyses confirm that increased MAFG signaling during DIO curbs lncRNA expression. Silencing
Mafg
in mouse hepatocytes and obese mice elicits a fasting-like gene expression profile, improves glucose metabolism, de-represses lncRNAs and impairs mammalian target of rapamycin (mTOR) activation. We find that obesity-repressed
LincIRS2
is controlled by MAFG and observe that genetic and RNAi-mediated
LincIRS2
loss causes elevated blood glucose, insulin resistance and aberrant glucose output in lean mice. Taken together, we identify a MAFG-lncRNA axis controlling hepatic glucose metabolism in health and metabolic disease.
Despite widespread transcription of LncRNA in mammalian systems, their contribution to metabolic homeostasis at the cellular and tissue level remains elusive. Here Pradas-Juni et al. describe a transcription factor–LncRNA pathway that couples hepatocyte nutrient sensing to regulation of glucose metabolism in mice.
Journal Article
Fatty acid synthesis suppresses dietary polyunsaturated fatty acid use
2024
Dietary polyunsaturated fatty acids (PUFA) are increasingly recognized for their health benefits, whereas a high production of endogenous fatty acids – a process called de novo lipogenesis (DNL) - is closely linked to metabolic diseases. Determinants of PUFA incorporation into complex lipids are insufficiently understood and may influence the onset and progression of metabolic diseases. Here we show that fatty acid synthase (FASN), the key enzyme of DNL, critically determines the use of dietary PUFA in mice and humans. Moreover, the combination of FASN inhibition and PUFA-supplementation decreases liver triacylglycerols (TAG) in mice fed with high-fat diet. Mechanistically, FASN inhibition causes higher PUFA uptake via the lysophosphatidylcholine transporter MFSD2A, and a diacylglycerol O-acyltransferase 2 (DGAT2)-dependent incorporation of PUFA into TAG. Overall, the outcome of PUFA supplementation may depend on the degree of endogenous DNL and combining PUFA supplementation and FASN inhibition might be a promising approach to target metabolic disease.
Polyunsaturated Fatty Acids (PUFA), such as omega-3 fatty acids, are recognized for their lipid lowering and anti-inflammatory properties. Here, the authors show that endogenous lipid synthesis controls the use of PUFA and thus determine the therapeutic benefit of omega-3 fatty acid supplementation.
Journal Article
A Polyclonal Selex Aptamer Library Directly Allows Specific Labelling of the Human Gut Bacterium Blautia producta without Isolating Individual Aptamers
2022
Recent studies have demonstrated that changes in the abundance of the intestinal bacterium Blautia producta, a potential probiotic, are closely associated with the development of various diseases such as obesity, diabetes, some neurodegenerative diseases, and certain cancers. However, there is still a lack of an effective method to detect the abundance of B. producta in the gut rapidly. Especially, DNA aptamers are now widely used as biometric components for medical testing due to their unique characteristics, including high chemical stability, low production cost, ease of chemical modification, low immunogenicity, and fast reproducibility. We successfully obtained a high-affinity nucleic acid aptamer library (B.p-R14) after 14 SELEX rounds, which efficiently discriminates B. producta in different analysis techniques including fluorometric suspension assays or fluorescence microscopy from other major gut bacteria in complex mixtures and even in human stool samples. These preliminary findings will be the basis towards aptamer-based biosensing applications for the fast and reliable monitoring of B. producta in the human gut microbiome.
Journal Article
Obesity-induced overexpression of miR-802 impairs glucose metabolism through silencing of Hnf1b
2013
The livers of obese mice and humans show increased levels of miR-802 resulting in impaired glucose tolerance and decreased insulin sensitivity through silencing of
Hnf1b
, revealing a novel pathway with potential relevance for type 2 diabetes.
A microRNA linked to glucose metabolism
Regulation of gene expression by microRNAs is known to have a role in various diseases, including type 2 diabetes. Here it is shown that the level of miR-802 is increased in the livers of obese mice and humans. Overexpression of miR-802 results in impaired glucose tolerance and insulin actions, whereas its reduction improves glucose tolerance and insulin sensitivity. It is further shown that miR-802-dependent silencing of
Hnf1b
(also called
Tcf2
) mediates these effects. This work suggests that both miR-802 and Hnf1b are potential therapeutic targets.
Insulin resistance represents a hallmark during the development of type 2 diabetes mellitus and in the pathogenesis of obesity-associated disturbances of glucose and lipid metabolism
1
,
2
,
3
. MicroRNA (miRNA)-dependent post-transcriptional gene silencing has been recognized recently to control gene expression in disease development and progression, including that of insulin-resistant type 2 diabetes. The deregulation of miRNAs miR-143 (ref.
4
), miR-181 (ref.
5
), and miR-103 and miR-107 (ref.
6
) alters hepatic insulin sensitivity. Here we report that the expression of miR-802 is increased in the liver of two obese mouse models and obese human subjects. Inducible transgenic overexpression of miR-802 in mice causes impaired glucose tolerance and attenuates insulin sensitivity, whereas reduction of miR-802 expression improves glucose tolerance and insulin action. We identify
Hnf1b
(also known as
Tcf2
) as a target of miR-802-dependent silencing, and show that short hairpin RNA (shRNA)-mediated reduction of Hnf1b in liver causes glucose intolerance, impairs insulin signalling and promotes hepatic gluconeogenesis. In turn, hepatic overexpression of Hnf1b improves insulin sensitivity in
Lepr
db/db
mice. Thus, this study defines a critical role for deregulated expression of miR-802 in the development of obesity-associated impairment of glucose metabolism through targeting of
Hnf1b
, and assigns Hnf1b an unexpected role in the control of hepatic insulin sensitivity.
Journal Article
Stem Cell-Based Therapy: A Promising Treatment for Diabetic Foot Ulcer
by
Hinterseher, Irene
,
Arnold, Tobias
,
Knippschild, Uwe
in
Amputation
,
Angiogenesis
,
Angioplasty
2022
Diabetic foot ulcer (DFU) is a severe complication of diabetes and a challenging medical condition. Conventional treatments for DFU have not been effective enough to reduce the amputation rates, which urges the need for additional treatment. Stem cell-based therapy for DFU has been investigated over the past years. Its therapeutic effect is through promoting angiogenesis, secreting paracrine factors, stimulating vascular differentiation, suppressing inflammation, improving collagen deposition, and immunomodulation. It is controversial which type and origin of stem cells, and which administration route would be the most optimal for therapy. We reviewed the different types and origins of stem cells and routes of administration used for the treatment of DFU in clinical and preclinical studies. Diabetes leads to the impairment of the stem cells in the diseased patients, which makes it less ideal to use autologous stem cells, and requires looking for a matching donor. Moreover, angioplasty could be complementary to stem cell therapy, and scaffolds have a positive impact on the healing process of DFU by stem cell-based therapy. In short, stem cell-based therapy is promising in the field of regenerative medicine, but more studies are still needed to determine the ideal type of stem cells required in therapy, their safety, proper dosing, and optimal administration route.
Journal Article
Regulation of MHC I Molecules in Glioblastoma Cells and the Sensitizing of NK Cells
by
Zhanapiya, Anuar
,
Bulach, Christiane
,
Gihring, Adrian
in
Antibodies
,
Antigen presentation
,
Apoptosis
2021
Immunotherapy has been established as an important area in the therapy of malignant diseases. Immunogenicity sufficient for immune recognition and subsequent elimination can be bypassed by tumors through altered and/or reduced expression levels of major histocompatibility complex class I (MHC I) molecules. Natural killer (NK) cells can eliminate tumor cells in a MHC I antigen presentation-independent manner by an array of activating and inhibitory receptors, which are promising candidates for immunotherapy. Here we summarize the latest findings in recognizing and regulating MHC I molecules that affect NK cell surveillance of glioblastoma cells.
Journal Article
Assessing the Inhibitory Potential of Kinase Inhibitors In Vitro: Major Pitfalls and Suggestions for Improving Comparability of Data Using CK1 Inhibitors as an Example
by
Gihring, Adrian
,
Göser, Florian
,
Roth, Aileen
in
Casein Kinase I - antagonists & inhibitors
,
Cell division
,
Enzyme Assays - methods
2021
Phosphorylation events catalyzed by protein kinases represent one of the most prevalent as well as important regulatory posttranslational modifications, and dysregulation of protein kinases is associated with the pathogenesis of different diseases. Therefore, interest in developing potent small molecule kinase inhibitors has increased enormously within the last two decades. A critical step in the development of new inhibitors is cell-free in vitro testing with the intention to determine comparable parameters like the commonly used IC50 value. However, values described in the literature are often biased as experimental setups used for determination of kinase activity lack comparability due to different readout parameters, insufficient normalization or the sheer number of experimental approaches. Here, we would like to hold a brief for highly sensitive, radioactive-based in vitro kinase assays especially suitable for kinases exhibiting autophosphorylation activity. Therefore, we demonstrate a systematic workflow for complementing and validating results from high-throughput screening as well as increasing the comparability of enzyme-specific inhibitor parameters for radiometric as well as non-radiometric assays. Using members of the CK1 family of serine/threonine-specific protein kinases and established CK1-specific inhibitors as examples, we clearly demonstrate the power of our proposed workflow, which has the potential to support the generation of more comparable data for biological characterization of kinase inhibitors.
Journal Article
Influence of bariatric surgery on the peripheral blood immune system of female patients with morbid obesity revealed by high-dimensional mass cytometry
2023
Obesity is associated with low-grade chronic inflammation, altered levels of adipocytokines, and impaired regulation of gastrointestinal hormones. Secreted, these factors exert immunostimulatory functions directly influencing peripheral immune cells.
In the realm of this study, we aimed to investigate the composition and activation status of peripheral blood immune cells in female patients with morbid obesity compared to lean controls using high-dimensional mass cytometry. Besides, we also assessed the influence of bariatric surgery with respect to its ability to reverse obesity-associated alterations within the first-year post-surgery.
Patients with morbid obesity showed typical signs of chronic inflammation characterized by increased levels of CRP and fibrinogen. Apart from that, metabolic alterations were characterized by increased levels of leptin and resistin as well as decreased levels of adiponectin and ghrelin compared to the healthy control population. All these however, except for ghrelin levels, rapidly normalized after surgery with regard to control levels. Furthermore, we found an increased population of monocytic CD14
, HLA-DR
, CD11b
, CXCR3
cells in patients with morbid obesity and an overall reduction of the HLA-DR monocytic expression compared to the control population. Although CD14
, HLA-DR
, CD11b
, CXCR3
decreased after surgery, HLA-DR expression did not recover within 9 - 11 months post-surgery. Moreover, compared to the control population, patients with morbid obesity showed a perturbed CD4+ T cell compartment, characterized by a strongly elevated CD127
memory T cell subset and decreased naïve T cells, which was not recovered within 9 - 11 months post-surgery. Although NK cells showed an activated phenotype, they were numerically lower in patients with morbid obesity when compared to healthy controls. The NK cell population further decreased after surgery and did not recover quantitatively within the study period.
Our results clearly demonstrate that the rapid adaptions in inflammatory parameters and adipocytokine levels that occur within the first year post-surgery do not translate to the peripheral immune cells. Apart from that, we described highly affected, distinct immune cell subsets, defined as CD127
memory T cells and monocytic CD14
, HLA-DR, CD11b
, CXCR3
cells, that might play a significant role in understanding and further decoding the etiopathogenesis of morbid obesity.
Journal Article
CK1 Is a Druggable Regulator of Microtubule Dynamics and Microtubule-Associated Processes
2022
Protein kinases of the Casein Kinase 1 family play a vital role in the regulation of numerous cellular processes. Apart from functions associated with regulation of proliferation, differentiation, or apoptosis, localization of several Casein Kinase 1 isoforms to the centrosome and microtubule asters also implicates regulatory functions in microtubule dynamic processes. Being localized to the spindle apparatus during mitosis Casein Kinase 1 directly modulates microtubule dynamics by phosphorylation of tubulin isoforms. Additionally, site-specific phosphorylation of microtubule-associated proteins can be related to the maintenance of genomic stability but also microtubule stabilization/destabilization, e.g., by hyper-phosphorylation of microtubule-associated protein 1A and RITA1. Consequently, approaches interfering with Casein Kinase 1-mediated microtubule-specific functions might be exploited as therapeutic strategies for the treatment of cancer. Currently pursued strategies include the development of Casein Kinase 1 isoform-specific small molecule inhibitors and therapeutically useful peptides specifically inhibiting kinase-substrate interactions.
Journal Article