Transcription Factors with Broad Expression in the Zebrafish Spinal Cord

Background

The spinal cord is a crucial part of the vertebrate central nervous system, controlling movements and receiving and processing sensory information from the trunk and limbs. However, there is much we do not know about how this essential organ develops. Here, we describe expression of 22 transcription factor genes in the zebrafish spinal cord.

Results

We analyzed the spinal cord expression of aurkb, foxb1a, foxb1b, her8a, homeza, ivns1abpb, mybl2b, myt1a, nr2f1b, onecut1, sall1a, sall3a, sall3b, sall4, sox2, sox19b, sp8b, tsc22d1, wdhd1, zfhx3b, znf804a, and znf1032 in wild-type and MIB E3 ubiquitin protein ligase 1 zebrafish embryos. While all of these genes are broadly expressed in the spinal cord, they have distinct expression patterns from one another. Some are predominanatly expressed in progenitor domains, and others in subsets of post-mitotic cells. Given the conservation of spinal cord development, and the transcription factors that regulate it, we expect that these genes will have similar spinal cord expression patterns in other vertebrates, including mammals and humans.

Conclusions

Our data identify 22 different transcription factors that are strong candidates for playing different roles in spinal cord development. For several of these genes, this is the first published description of their spinal cord expression.

Molecular analyses of zebrafish V0v spinal interneurons and identification of transcriptional regulators downstream of Evx1 and Evx2 in these cells

BACKGROUND

V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells.

METHODS

To identify candidate members of V0v gene regulatory networks, we FAC-sorted wild-type and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings.

RESULTS

Our data reveal two molecularly distinct subtypes of zebrafish V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuron expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression.

CONCLUSIONS

This study identifies two molecularly distinct subsets of zebrafish V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.

Molecular Analyses of V0v Spinal Interneurons and Identification of Transcriptional Regulators Downstream of Evx1 and Evx2 in these Cells

Background

V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells.

Methods

To identify candidate members of V0v gene regulatory networks, we FAC-sorted WT and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings.

Results

Our data reveal two molecularly distinct subtypes of V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuronal expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression.

Conclusions

This study identifies two molecularly distinct subsets of V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.

Analyses of binding partners and functional domains for the developmentally essential protein Hmx3a/HMX3

HMX3 is a homeodomain protein with essential roles in CNS and ear development. Homeodomains are DNA-binding domains and hence homeodomain-containing proteins are usually assumed to be transcription factors. However, intriguingly, our recent data suggest that zebrafish Hmx3a may not require its homeodomain to function, raising the important question of what molecular interactions mediate its effects. To investigate this, we performed a yeast two-hybrid screen and identified 539 potential binding partners of mouse HMX3. Using co-immunoprecipitation, we tested whether a prioritized subset of these interactions are conserved in zebrafish and found that Tle3b, Azin1b, Prmt2, Hmgb1a, and Hmgn3 bind Hmx3a. Next, we tested whether these proteins bind the products of four distinct hmx3a mutant alleles that all lack the homeodomain. Embryos homozygous for two of these alleles develop abnormally and die, whereas zebrafish homozygous for the other two alleles are viable. We found that all four mutations abrogate binding to Prmt2 and Tle3b, whereas Azin1b binding was preserved in all cases. Interestingly, Hmgb1a and Hmgn3 had more affinity for products of the viable mutant alleles. These data shed light on how HMX3/Hmx3a might function at a molecular level and identify new targets for future study in these vital developmental processes.

Targeted therapies and checkpoint inhibitors in sarcoma

Sarcomas are defined as a group of mesenchymal malignancies with over 100 heterogeneous subtypes. As a rare and difficult to diagnose entity, micrometastasis is already present at the time of diagnosis in many cases. Current treatment practice of sarcomas consists mainly of surgery, (neo)adjuvant chemo- and/or radiotherapy. Although the past decade has shown that particular genetic abnormalities can promote the development of sarcomas, such as translocations, gain-of-function mutations, amplifications or tumor suppressor gene losses, these insights have not led to established alternative treatment strategies so far. Novel therapeutic concepts with immunotherapy at its forefront have experienced some remarkable success in different solid tumors while their impact in sarcoma remains limited. In this review, the most common immunotherapy strategies in sarcomas, such as immune checkpoint inhibitors, targeted therapy and cytokine therapy are concisely discussed. The programmed cell death (PD)-1/PD-1L axis and apoptosis-inducing cytokines, such as TNF-related apoptosis-inducing ligand (TRAIL), have not yielded the same success like in other solid tumors. However, in certain sarcoma subtypes, e.g. liposarcoma or undifferentiated pleomorphic sarcoma, encouraging results in some cases when employing immune checkpoint inhibitors in combination with other treatment options were found. Moreover, newer strategies such as the targeted therapy against the ancient cytokine macrophage migration inhibitory factor (MIF) may represent an interesting approach worth investigation in the future.

Evolution of lbx spinal cord expression and function

Ladybird homeobox (Lbx) transcription factors have crucial functions in muscle and nervous system development in many animals. Amniotes have two Lbx genes, but only Lbx1 is expressed in spinal cord. In contrast, teleosts have three lbx genes and we show here that zebrafish lbx1a, lbx1b, and lbx2 are expressed by distinct spinal cell types, and that lbx1a is expressed in dI4, dI5, and dI6 interneurons, as in amniotes. Our data examining lbx expression in Scyliorhinus canicula and Xenopus tropicalis suggest that the spinal interneuron expression of zebrafish lbx1a is ancestral, whereas lbx1b has acquired a new expression pattern in spinal cord progenitor cells. lbx2 spinal expression was probably acquired in the ray-finned lineage, as this gene is not expressed in the spinal cords of either amniotes or S. canicula. We also show that the spinal function of zebrafish lbx1a is conserved with mouse Lbx1. In zebrafish lbx1a mutants, there is a reduction in the number of inhibitory spinal interneurons and an increase in the number of excitatory spinal interneurons, similar to mouse Lbx1 mutants. Interestingly, the number of inhibitory spinal interneurons is also reduced in lbx1b mutants, although in this case the number of excitatory interneurons is not increased. lbx1a;lbx1b double mutants have a similar spinal interneuron phenotype to lbx1a single mutants. Taken together these data suggest that lbx1b and lbx1a may be required in succession for correct specification of dI4 and dI6 spinal interneurons, although only lbx1a is required for suppression of excitatory fates in these cells.

Hmx3a Has Essential Functions in Zebrafish Spinal Cord, Ear and Lateral Line Development

Transcription factors that contain a homeodomain DNA-binding domain have crucial functions in most aspects of cellular function and embryonic development in both animals and plants. Hmx proteins are a subfamily of NK homeodomain-containing proteins that have fundamental roles in development of sensory structures such as the eye and the ear. However, Hmx functions in spinal cord development have not been analyzed. Here, we show that zebrafish (Danio rerio) hmx2 and hmx3a are coexpressed in spinal dI2 and V1 interneurons, whereas hmx3b, hmx1, and hmx4 are not expressed in spinal cord. Using mutational analyses, we demonstrate that, in addition to its previously reported role in ear development, hmx3a is required for correct specification of a subset of spinal interneuron neurotransmitter phenotypes, as well as correct lateral line progression and survival to adulthood. Surprisingly, despite similar expression patterns of hmx2 and hmx3a during embryonic development, zebrafish hmx2 mutants are viable and have no obviously abnormal phenotypes in sensory structures or neurons that require hmx3a In addition, embryos homozygous for deletions of both hmx2 and hmx3a have identical phenotypes to severe hmx3a single mutants. However, mutating hmx2 in hypomorphic hmx3a mutants that usually develop normally, results in abnormal ear and lateral line phenotypes. This suggests that while hmx2 cannot compensate for loss of hmx3a, it does function in these developmental processes, although to a much lesser extent than hmx3a More surprisingly, our mutational analyses suggest that Hmx3a may not require its homeodomain DNA-binding domain for its roles in viability or embryonic development.

[Wnt signaling in cutaneous wound healing]

Human skin is an efficient barrier that protects the organism from noxious substances. Wounds destroy this barrier. Wound healing is a phased physiological regeneration of the destroyed tissue that ideally leads to occlusion of a wound, in particular by regeneration of connective tissue and capillaries. The Wnt signaling pathway is a highly conserved signal transduction cascade across the animal kingdom that controls basic cellular interactions in multicellular organisms. Accordingly, through the Wnt signaling path many processes, e. g. as the balance between proliferation and differentiation or apoptosis, coordinated. Wnt signaling is activated by a wound and participates in each subsequent phase of the healing process, beginning with inflammatory control and programmed cell death, to the mobilization of stem cells within the wound. Endogenous Wnt signaling is an attractive therapeutic approach to assist in the repair of skin wounds, as the complex mechanisms of the Wnt signaling pathway have become increasingly understood over the years. This review summarizes current data to clarify the role of Wnt signaling in the wound healing process of the skin.

Antibiotikatherapie von Infektionen bei Verbrennungspatienten – Eine systematische Übersichtsarbeit

Hintergrund Durch den Verlust der natürlichen Hautbarrierefunktion und folglich reduzierter Immunkompetenz infolge eines Plasmaverlustes sowie zahlreichen intensivmedizinischen Interventionen sind Verbrennungspatienten besonders gefährdet für Infektionen.

Studiendesign Systematische Übersichtsarbeit

Methoden In einer systematischen Übersicht der deutsch- und englischsprachigen Literatur zwischen 1990 und 2018 werden epidemiologische und diagnostische Aspekte sowie der therapeutische Einsatz von Antibiotika bei Infektionen von Verbrennungspatienten in klinischen Studien analysiert.

Ergebnisse Insgesamt erfüllten 53 randomisiert kontrollierte klinische Studien die Auswahlkriterien. Untersucht wurden verschiedene Arten/Applikationsformen der antibiotischen Prophylaxe bei Verbrennungswunden: Topisch, systemisch (generell), systemisch (perioperativ), nicht absorbierbare Antibiotika (= selektive Darmdekontamination), lokal (inhaliert) und jegliche Applikationsformen versus Kontrolle. Die frühe „Postburn-Prophylaxe“ wurde bei Patienten mit geringgradiger Verbrennung (sechs Studien) und Patienten mit schwerer Verbrennung (sieben Studien) untersucht. Die antimikrobielle Prophylaxe zeigte keine präventive Wirksamkeit des toxischen Schocksyndroms bei geringgradigen Verbrennungen, ist aber bei Patienten mit schweren Verbrennungen und der Notwendigkeit einer mechanischen Beatmung nützlich. Die perioperative Prophylaxe (= Metaphylaxe) wurde in zehn Studien untersucht.

Schlussfolgerung Der Nutzen für eine längerfristige systemische antibiotische Prophylaxe bei der Mehrheit von Verbrennungspatienten ist nicht evident. Leichte Infektionen in stabilem klinischen Zustand sind engmaschig zu beobachten, während bei schwerer Infektion die internationalen Sepsis-Leitlinien und das Tarragona-Prinzip empfohlen werden.

[Regulation of bone metabolism by the Wnt signaling pathway]

The development and homeostasis of multicellular organisms depends on a complex cellular interaction between proliferation, migration, differentiation, adhesion, and cell death. Wnt signaling pathways coordinate these different cellular responses. Wnt signaling plays a role as a regulatory pathway in the osteogenic differentiation of mesenchymal stem cells. The Wnt signaling pathway is an attractive therapeutic target with the potential to directly modulate stem cells responsible for the regeneration of skeletal tissue. Recent studies indicate that Wnt ligands are capable of promoting bone growth, suggesting that Wnt factors could be used to stimulate bone healing in osteogenic disorders.

Unusual onset of adult still's disease due to a systemic reaction to artificial breast implants

In this manuscript, we report an exceptional observation study of a young woman suffering from an autoimmune syndrome induced by adjuvants (ASIA). Until today only seven cases of adult-onset Still's disease (AOSD) induced by breast implants have been published. This may be due to the fact that this illness itself is very rare; however, the reason might also be that the community is not sensitized to the case-specific symptoms. Within this article, we show for the first time highly detailed diagnostic test procedures such as PET-CT scans and specific histological staining of the breast tissue, displaying proinflammatory macrophages that are a well-known activator and booster of autoimmune diseases. We hope to give new insights into the clinical picture and pathogenesis of AOSD in order to improve the challenging diagnosis.

Management, clinical outcomes, and complications of acute cannula-related peripheral vein phlebitis of the upper extremity: A retrospective study

OBJECTIVE

Acute phlebitis due to peripheral vein catheter use is frequently observed in clinical practice, and requires surgical therapy in severe cases. In this retrospective study, we aimed to increase awareness, evaluate current treatment options, and develop recommendations to optimize treatment outcomes.

METHODS

A total of 240 hospitalized patients with a diagnosis of upper extremity phlebitis from 2006 to 2011 were evaluated in terms of initial clinical features, parameters, co-morbidities and treatment regimes. Severity of phlebitis was graded according to the Baxter scale by assessing clinical symptoms such as pain, erythema, induration, swelling, or palpable venous cord (grade 0-5). Patients were divided in two subgroups: conservative (n = 132) and operative (n = 108) treatment.

RESULTS

Surgical intervention rates and severity were higher for cannula insertion in the cubital fossa region than for cannula insertion in the forearm and hand region (p < 0.05). Baxter scale grades were higher in the surgical treatment group than in the conservative treatment group (4.47 vs. 2.67, respectively).

CONCLUSIONS

The cubital fossa region is vulnerable to severe phlebitis and is not recommended as the first site of choice for cannulation. Phlebitis of Baxter scale grade 4 or 5 should be considered for early surgical intervention.

Tissue substitutes with improved angiogenic capabilities: an in vitro investigation with endothelial cells and endothelial progenitor cells

The use of implantable biomaterials, such as artificial skin substitutes used for dermal defects, remains limited by the low angiogenic potential of these products. The rapid in vivo degradation of growth factors contributes to the limiting of angiogenesis in biomaterials. Here, we report on collagen sponges in which vascular endothelial growth factor (VEGF) was immobilized through physical binding to heparin, covalently incorporated in the matrix via cross-linking with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide. The in vitro release of VEGF over time and endothelial cell proliferation were investigated in matrices modified at varying heparin to EDC ratios either nonloaded or loaded with VEGF. ELISA demonstrated a significantly slower in vitro release of VEGF over a period of 5 days from heparinized matrices as compared to their unmodified and cross-linked counterparts. The effects of these modifications on the proliferation of endothelial cells and endothelial progenitor cells were evaluated after 1, 3 and 5 days either according to the bromodeoxyuridine assay or total cell counting with a Neubauer chamber. The endothelial and endothelial progenitor cells cultured in contact with heparinized matrices loaded with VEGF revealed both the highest rate of DNA synthesis and the highest total cell count. Furthermore, these results show that the cross-linking of collagen matrices - both in the presence and absence of heparin - leads to increases of the proliferative activities. We can assume that these changes lead to matrices with increased angiogenic capabilities.

Enhancing angiogenesis in collagen matrices by covalent incorporation of VEGF

Since the survival of ingrowing cells in biomaterials for regenerative processes largely depends on the supply of nutrients and oxygen, angiogenesis plays an important role in the development of new materials for tissue engineering. In this study we investigated the possibility of enhancing the angiogenic properties of collagen matrices by covalent incorporation of the vascular endothelial growth factor (VEGF). In a previous paper we already reported the use of homo- and heterobifunctional cross-linking agents for modifying collagen matrices [1]. In the present work the angiogenic growth factor was linked to the collagen with the homobifunctional cross-linker disuccinimidyldisuccinatepolyethyleneglycol (SS-PEG-SS) in a two step procedure. The efficiency of the first reaction step-the reaction of SS-PEG-SS with VEGF--was evaluated by western blot analysis. After 10 minutes virtually all of the dimeric molecules VEGF were on average modified by conjugation with 1 cross-linking molecule. The biological activity of the conjugate was investigated by exposing endothelial cells to non-modified VEGF and to VEGF conjugated to the cross-linker. The conjugation only had a limited effect on the mitogenic activity of VEGF. We therefore applied the cross-linking reaction to the VEGF-collagen system. In a first approach the changes were evaluated by the in vitro exposure of HUVECs to non-modified matrices, to matrices in which the VEGF was simply admixed and to matrices in which the VEGF was covalently incorporated. The angiogenic properties were evaluated in vivo with the chorioallantois membrane model. In this assay the chorioallantois membrane of the chicken embryo was exposed to the same set of matrices. The covalent incorporation of VEGF has a small but significant effect both on the formation of microvessels in the chorioallantois membrane and the tissue ingrowth into the implant. The covalent incorporation of angiogenic growth factors may thus be considered as a promising approach for enhancing the angiogenic capabilities of collagen matrices. Also the cross-linking with the homobifunctional cross-linking agent has a positive effect on the angiogenic potential of the collagen matrices.