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result(s) for
"Luckner, Martin"
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Expansion of functional personalized cells with specific transgene combinations
2018
Fundamental research and drug development for personalized medicine necessitates cell cultures from defined genetic backgrounds. However, providing sufficient numbers of authentic cells from individuals poses a challenge. Here, we present a new strategy for rapid cell expansion that overcomes current limitations. Using a small gene library, we expanded primary cells from different tissues, donors, and species. Cell-type-specific regimens that allow the reproducible creation of cell lines were identified. In depth characterization of a series of endothelial and hepatocytic cell lines confirmed phenotypic stability and functionality. Applying this technology enables rapid, efficient, and reliable production of unlimited numbers of personalized cells. As such, these cell systems support mechanistic studies, epidemiological research, and tailored drug development.
Personalised medicine requires cell cultures from defined genetic backgrounds, but providing sufficient numbers of cells is a challenge. Here the authors develop gene cocktails to expand primary cells from a variety of different tissues and species, and show that expanded endothelial and hepatic cells retain properties of the differentiated phenotype.
Journal Article
Purification and characterization of lanatoside 15′-O-acetylesterase from Digitalis lanata Ehrh
by
Kandzia, Romy
,
Eckerskorn, Christoph
,
Luckner, Martin
in
Acetylesterase
,
Acetylesterase - chemistry
,
Acetylesterase - isolation & purification
1998
Lanatoside 15′-O-acetylesterase (LAE) from in-vitro-cultivated cells of Digitalis lanata Ehrh. was isolated and partially sequenced. The enzyme was extracted with citrate buffer from acetone dry powder. It was purified in a two-step chromatographical procedure including Phenyl Sepharose hydrophobic interaction chromatography followed by CM Sepharose cation-exchange chromatography to more than 330 μmol·s-1. (g protein)-1. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the purified protein showed a major band at 39 kDa. The protein was identified by correlation of band intensity on SDS-PAGE and enzyme activity of CM Sepharose column fractions. Size-exclusion chromatography on Sephacryl 200 revealed a single activity peak with an apparent molecular mass of about 85 kDa. Electrophoresis under nondenaturating conditions of purified LAE showed only one band with esterase activity. The intensity of this band was correlated with that of the 39-kDa band after SDS-PAGE. About 30% of the protein, including the Nterminus and several fragments obtained by Lys-C protease digestion, was sequenced. A fragment obtained by Lys-C digestion showed partial homology to other hydrolases and apoplasmic proteins. It included the probable location of an active-site histidine. The activity of LAE was high in non-morphogenic D. lanata cell strains selected for high activities in the chemical transformation of cardenolides, but rather low in the proembryogenic masses of the embryogenic cell strain VIII. It increased during the development of somatic embryos. The LAE activity in leaves of D. lanata plants was in the range 4—24 nmol·s-1·(g protein)-1.
Journal Article
Stress-induced expression cyclophilins in proembryonic masses of Digitalis lanata does not protect against freezing/thawing stress
by
Kullertz, G
,
Rucknagel, P
,
Fischer, G
in
abscisic acid
,
Adaptation, Physiological
,
Amino Acid Sequence
1999
Using proembryonic masses (PEMs) of Digitalis lanata Erh., it was demonstrated that cold hormonal or osmotic stress, which increased freezing tolerance during cryopreservation, induced an increasing level of two peptidyl-prolyl-cis/trans-isomerases (PPIases). The difference in pI (9.2 +/- 0.2 and 9.5 +/- 0.2, +/- SD; n = 3) allowed the separation of the two enzymes by free-flow isoelectrophoresis. Both were inhibited by cyclosporin A and thus belong to the cyclophilin family of PPIases. The enzymes differed slightly in their substrate specificity and their relative molecular masses of 18038 +/- 4 Da (D. lanataCyp18.0) and 18132 +/- 3 Da (D. lanataCyp18.1). Both cyclophilins were blocked N-terminally. Partial internal amino acid sequences from the two cyclophilins, with a length of 34 amino acids, displayed 82% sequence identity to each other Pretreatment of PEMs with abscisic acid, sorbitol or a combination of both substances led to a 270 +/- 30% elevation of the total cytosolic cyclophilin concentration determined with a cyclophylin affinity sensor. During the first 4 d of pretreatment, the total PPIase activity was enhanced up to 230 +/- SD% compared with the control culture. The lag phase between maximal PPIase concentration after 4 d of pretreatment and maximal effect of freezing tolerance after 10 d of pretreatment indicated that increasing levels of cytosolic PPIases may be necessary to overcome the stress induced by hormones and osmotica during pretreatment but not to protect against freezing/thawing stress.
Journal Article
Δ 5 -3β-Hydroxysteroid dehydrogenase from Digitalis lanata Ehrh. — a multifunctional enzyme in steroid metabolism?
by
Eckerskorn, Christoph
,
Luckner, Martin
,
Grimm, Rudolf
in
Amino acids
,
Biosynthesis
,
Cardenolides
1999
Δ5-3β-Hydroxysteroid dehydrogenase (Δ5-3β-HSD; EC 1.1.1.145), an enzyme converting pregn-5-ene-3β-ol-20-one (pregnenolone) to pregn-5-ene-3,20-dione (isoprogesterone), was isolated from the soluble fraction of suspension-cultured cells of Digitalis lanata L. strain VIII. Starting with acetone dry powder the enzyme was purified in three steps using column chromatography on Fractogel-TSK DEAE, hydroxyapatite and Sephacryl G-200. Fractions with highest Δ5-3β-HSD activity were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After in-situ digestion the resulting bands were sequenced N-terminally. The 29-kDa band yielded three fragments with high sequence homology to members of the superfamily of short-chain dehydrogenases/reductases. High similarity was found to microbial hydroxysteroid dehydrogenases. The band may therefore represent the Δ5-3β-HSD. The purified enzyme was characterized with respect to kinetic parameters, substrate specificity and localization. The function of the enzyme in steroid metabolism is discussed.
Journal Article
Cardenolide 16'-O-glucohydrolase from Digitalis lanata. Purification and characterization
by
Grimm, R
,
Luckner, M
,
Eckerskorn, C
in
Amino Acid Sequence
,
amino acid sequences
,
Analytical, structural and metabolic biochemistry
1998
A three-step chromatographic procedure was developed for purification of cardenolide 16'-O-glucohydrolase (CGH) from Digitalis lanata Ehrh. leaves, including Phenyl-Sepharose hydrophobic interaction chromatography followed by SP-Sepharose cation exchange and Q-Sepharose anion-exchange chromatography. Starting with acetone dry powder the purification resulted in an 760-fold enrichment of CGH. Molecular weight, substrate specificity, pH optimum and temperature stability of CGH were determined. Antibodies against CGH were prepared in rabbits. The SDS gel electrophoresis of protein extracts from leaves of D. lanata and other D. species showed bands at 70 kDa and 36 kDa reacting with the antibodies. The 70-kDa protein is the main protein stained with CGH antibodies in freshly prepared extracts of D. lanata. It may represent undegraded CGH. The 36-kDa protein is enriched in aged CGH preparations. It is probably a degradation product. Proteins related to 70-kDa and 36-kDa bands also occur in crude protein preparations from leaves of D. heywoodii P. et M. Silva, D. mariana Boiss., D. purpurea L., and D. thapsi L. indicating that CGH is also present in these species. Purified CGH was digested with proteases V8 and Lys-C and the resulting fragments obtained were sequenced. One fragment had the typical amino-acid sequence of the catalytic center of family-1 glycosyl hydrolases (EC 3.2.1.x). Cardenolide 16'-O-glucohydrolase, like the other members of this enzyme family, appeared to have a glutamic acid residue directly involved in glycosidic bond cleavage as a nucleophile.
Journal Article
Adverse cardiac events during catecholamine vasopressor therapy: a prospective observational study
by
Schmittinger, Christian A.
,
Torgersen, Christian
,
Luckner, Günter
in
Aged
,
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
,
Anesthesiology
2012
Purpose
To determine the incidence of and risk factors for adverse cardiac events during catecholamine vasopressor therapy in surgical intensive care unit patients with cardiovascular failure.
Methods
The occurrence of any of seven predefined adverse cardiac events (prolonged elevated heart rate, tachyarrhythmia, myocardial cell damage, acute cardiac arrest or death, pulmonary hypertension-induced right heart dysfunction, reduction of systemic blood flow) was prospectively recorded during catecholamine vasopressor therapy lasting at least 12 h.
Results
Fifty-four of 112 study patients developed a total of 114 adverse cardiac events, an incidence of 48.2 % (95 % CI, 38.8–57.6 %). New-onset tachyarrhythmia (49.1 %), prolonged elevated heart rate (23.7 %), and myocardial cell damage (17.5 %) occurred most frequently. Aside from chronic liver diseases, factors independently associated with the occurrence of adverse cardiac events included need for renal replacement therapy, disease severity (assessed by the Simplified Acute Physiology Score II), number of catecholamine vasopressors (OR, 1.73; 95 % CI, 1.08–2.77;
p
= 0.02) and duration of catecholamine vasopressor therapy (OR, 1.01; 95 % CI, 1–1.01;
p
= 0.002). Patients developing adverse cardiac events were on catecholamine vasopressors (
p
< 0.001) and mechanical ventilation (
p
< 0.001) for longer and had longer intensive care unit stays (
p
< 0.001) and greater mortality (25.9 vs. 1.7 %;
p
< 0.001) than patients who did not.
Conclusions
Adverse cardiac events occurred in 48.2 % of surgical intensive care unit patients with cardiovascular failure and were related to morbidity and mortality. The extent and duration of catecholamine vasopressor therapy were independently associated with and may contribute to the pathogenesis of adverse cardiac events.
Journal Article
Comparing two different arginine vasopressin doses in advanced vasodilatory shock: a randomized, controlled, open-label trial
2010
Purpose
To compare the effects of two arginine vasopressin (AVP) dose regimens on the hemodynamic response, catecholamine requirements, AVP plasma concentrations, organ function and adverse events in advanced vasodilatory shock.
Methods
In this prospective, controlled, open-label trial, patients with vasodilatory shock due to sepsis, systemic inflammatory response syndrome or after cardiac surgery requiring norepinephrine >0.6 μg/kg/min were randomized to receive a supplementary AVP infusion either at 0.033 IU/min (
n
= 25) or 0.067 IU/min (
n
= 25). The hemodynamic response, catecholamine doses, laboratory and organ function variables as well as adverse events (decrease in cardiac index or platelet count, increase in liver enzymes or bilirubin) were recorded before, 1, 12, 24 and 48 h after randomization. A linear mixed effects model was used for statistical analysis in order to account for drop-outs during the observation period.
Results
Heart rate and norepinephrine requirements decreased while MAP increased in both groups. Patients receiving AVP at 0.067 IU/min required less norepinephrine (
P
= 0.006) than those infused with AVP at 0.033 IU/min. Arterial lactate and base deficit decreased while arterial pH increased in both groups. During the observation period, AVP plasma levels increased in both groups (both
P
< 0.001), but were higher in the 0.067 IU/min group (
P
< 0.001) and in patients on concomitant hydrocortisone. The rate of adverse events and intensive care unit mortality was comparable between groups (0.033 IU/min, 52%; 0.067 IU/min, 52%;
P
= 1).
Conclusions
A supplementary AVP infusion of 0.067 IU/min restores cardiovascular function in patients with advanced vasodilatory shock more effectively than AVP at 0.033 IU/min.
Journal Article
Arterial blood pressure during early sepsis and outcome
by
Daudel, Fritz
,
Mayr, Viktoria D.
,
Jakob, Stephan M.
in
Aged
,
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
,
Anesthesiology
2009
Objective
To evaluate the association between arterial blood pressure (ABP) during the first 24 h and mortality in sepsis.
Design
Retrospective cohort study.
Setting
Multidisciplinary intensive care unit (ICU).
Patients and participants
A total of 274 septic patients.
Interventions
None.
Measurements and results
Hemodynamic, and laboratory parameters were extracted from a PDMS database. The hourly time integral of ABP drops below clinically relevant systolic arterial pressure (SAP), mean arterial pressure (MAP), and mean perfusion pressure (MPP = MAP − central venous pressure) levels was calculated for the first 24 h after ICU admission and compared with 28-day-mortality. Binary and linear regression models (adjusted for SAPS II as a measure of disease severity), and a receiver operating characteristic (ROC) analysis were applied. The areas under the ROC curve were largest for the hourly time integrals of ABP drops below MAP 60 mmHg (0.779 vs. 0.764 for ABP drops below MAP 55 mmHg;
P ≤
0.01) and MPP 45 mmHg. No association between the hourly time integrals of ABP drops below certain SAP levels and mortality was detected. One or more episodes of MAP < 60 mmHg increased the risk of death by 2.96 (CI 95%, 1.06–10.36,
P
= 0.04). The area under the ROC curve to predict the need for renal replacement therapy was highest for the hourly time integral of ABP drops below MAP 75 mmHg.
Conclusions
A MAP level ≥ 60 mmHg may be as safe as higher MAP levels during the first 24 h of ICU therapy in septic patients. A higher MAP may be required to maintain kidney function.
Journal Article
The course of adrenomedullin and endothelin levels in patients with vasodilatory shock after cardiac surgery compared to patients after uncomplicated elective cardiac surgery
by
Luger, Markus
,
Tauber, Helmuth
,
Mayr, Viktoria D.
in
Adrenomedullin
,
Biomarkers
,
Cardiac surgery
2022
The aim of this study was to analyse the course of adrenomedullin (ADM) and endothelin-1 (ET-1) levels in patients with vasodilatory shock after cardiac surgery and to explore differences compared to patients after uncomplicated coronary artery bypass graft (CABG) surgery. ADM and ET-1 are involved in the vasomotor response during vasodilatory shock.
We included 32 patients with vasodilatory shock (study group) and 10 patients after uncomplicated CABG surgery (control group). Daily measurements of MR-proADM and CT-proET-1 (stable surrogate markers for ADM and ET-1) were collected during the first 7 postoperative days.
MR-proADM and CT-proET-1 levels were significantly elevated in the study group when compared to the control group. In addition, the course of both biomarkers was significantly different in the study versus control group. Higher levels of both biomarkers were associated with organ dysfunction (higher maximum multiple organ dysfunction score, acute kidney injury).
Significantly higher levels of MR-proADM and CT-proET-1 and a different course of both biomarkers were observed in patients with vasodilatory shock after cardiac surgery and seemed to be associated with organ dysfunction.
•Significantly higher levels of MR-proADM and CT-proET-1 in patients with vasodilatory shock after cardiac surgery.•Different course of both biomarkers in patients with vasodilatory shock.•Seem to be associated with organ dysfunction.
Journal Article
RNAi-based small molecule repositioning reveals clinically approved urea-based kinase inhibitors as broadly active antivirals
by
Welke, Robert-William
,
Meyer, Michael
,
Weege, Friderike
in
Antiviral activity
,
Antiviral agents
,
Antiviral drugs
2019
Influenza viruses (IVs) tend to rapidly develop resistance to virus-directed vaccines and common antivirals targeting pathogen determinants, but novel host-directed approaches might preclude resistance development. To identify the most promising cellular targets for a host-directed approach against influenza, we performed a comparative small interfering RNA (siRNA) loss-of-function screen of IV replication in A549 cells. Analysis of four different IV strains including a highly pathogenic avian H5N1 strain, an influenza B virus (IBV) and two human influenza A viruses (IAVs) revealed 133 genes required by all four IV strains. According to gene enrichment analyses, these strain-independent host genes were particularly enriched for nucleocytoplasmic trafficking. In addition, 360 strain-specific genes were identified with distinct patterns of usage for IAVs versus IBV and human versus avian IVs. The strain-independent host genes served to define 43 experimental and otherwise clinically approved drugs, targeting reportedly fourteen of the encoded host factors. Amongst the approved drugs, the urea-based kinase inhibitors (UBKIs) regorafenib and sorafenib exhibited a superior therapeutic window of high IV antiviral activity and low cytotoxicity. Both UBKIs appeared to block a cell signaling pathway involved in IV replication after internalization, yet prior to vRNP uncoating. Interestingly, both compounds were active also against unrelated viruses including cowpox virus (CPXV), hantavirus (HTV), herpes simplex virus 1 (HSV1) and vesicular stomatitis virus (VSV) and showed antiviral efficacy in human primary respiratory cells. An in vitro resistance development analysis for regorafenib failed to detect IV resistance development against this drug. Taken together, the otherwise clinically approved UBKIs regorafenib and sorafenib possess high and broad-spectrum antiviral activity along with substantial robustness against resistance development and thus constitute attractive host-directed drug candidates against a range of viral infections including influenza.
Journal Article