Genetically Engineered Exosomes as a Potential Regulator of Th1 Cells Response in Rheumatoid Arthritis.

Background: Rheumatoid arthritis is a long-lasting inflammatory disease that usually involves joints, but it can also affect other organs, including the skin and lungs. In this case, it is important to maintain a balance between beneficial pro-inflammatory activity and harmful overactivation of the T helper cells (Th). We strive to investigate in this study the possibilities for the effect of mesenchymal stem cells (MSCs)-derived exosomes containing miR-146a/miR-155 on the lymphocyte population and function. Methods: Exosomes were isolated from overexpressed miR-146a/miR-155 MSCs for the purpose of this analysis. Splenocytes were isolated from collagen-induced arthritis (CIA) and control mice. It was important to consider the expressions of certain predominant autoimmune-response genes, including T-bet and interferon-γ (IFNγ), by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. It turned out to be a significant consideration with p < 0.05. Results: The results are expressed in percentages with respect to miR-146a/AntimiR-155 transduced MSC-derived exosomes treatment, which significantly decreased the mRNA expression level of IFNγ in healthy mice (p < 0.05). miR-146a transduced MSC-derived exosomes treatment significantly reduced the mRNA expression level of IFNγ in CIA mice (p < 0.05). It should be noted that the secretion of the pro-inflammatory factor IFNγ in CIA mice was inhibited in almost all groups (p < 0.05). Conclusion: Many research groups have mainly focused on strategies for reducing pro-inflammatory cytokines. This approach was recently suggested and investigated in our research team and suggested that manipulation of MSCs-derived exosomes could minimize pro-inflammatory cytokine production to strike a balance among Th subsets. These approaches tend to appear to achieve better results in the regulation of the immune system by the use of engineered exosomes derived from MSCs. By providing accurate information the reasonably practicable use of exosomes for cell-free therapy can be established.

Long noncoding RNA taurine-up regulated gene 1 for the prognosis of osteosarcoma: A protocol for meta-analysis and bioinformatics analysis.

BACKGROUND: In recent years, a variety of long noncoding RNA (lncRNA) has been confirmed to be involved in the initiation and progression of osteosarcoma. Taurine-up regulated gene 1 (TUG1) plays an important role in the formation, invasion, and metastasis of osteosarcoma. Therefore, perhaps TUG1 is a potential biomarker for the prognosis of patients suffering from osteosarcoma. In this study, meta-analysis and bioinformatics were adopted to further explore the effects of TUG1 on the prognosis of patients with osteosarcoma and its potential molecular mechanism. METHODS: Embase, PubMed, Sinomed, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Wanfang database, and Vip Journal Integration Platform were searched from inception to May 2021. The relationship between TUG1 expression and survival outcome was estimated by hazard ratio (HRs) and 95% confidence interval (CIs). Meta-analysis was conducted on the Stata 16.0. The differential expression of TUG1 in osteosarcoma was analyzed by using UALCAN database, and the survival of TUG1 was analyzed as well. The target genes of TUG1 were predicted by RegRNA2.0 biology software, HMDD, targetscan and microTCDS, and TUG1-micoRNAs-mRNAs regulatory network was constructed. The predicted target genes obtained GeneOntology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal transduction pathway enrichment analysis using FunRich platform. RESULTS: The results of this meta-analysis would be submitted to peer-reviewed journals for publication. CONCLUSION: This study will provide evidence-based medical evidence for the relationship between TUG1 and the prognosis of osteosarcoma. Furthermore, bioinformatics analysis will provide ideas for the exploration on osteosarcoma mechanism. ETHICS AND DISSEMINATION: The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results will be published in a peer-reviewed journal or disseminated in relevant conferences. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/CW4BF.

Pathogenesis, diagnosis and management of dentin hypersensitivity: an evidence-based overview for dental practitioners.

Though dentin hypersensitivity (DHS) is one of the most common complaints from patients in dental clinics, there are no universally accepted guidelines for differential diagnosis as well as selection of reliable treatment modalities for this condition. The neurosensory mechanisms underlying DHS remain unclear, but fluid movements within exposed dentinal tubules, i.e., the hydrodynamic theory, has been a widely accepted explanation for DHS pain. As several dental conditions have symptoms that mimic DHS at different stages of their progression, diagnosis and treatment of DHS are often confusing, especially for inexperienced dental practitioners. In this paper we provide an up-to-date review on risk factors that play a role in the development and chronicity of DHS and summarize the current principles and strategies for differential diagnosis and management of DHS in dental practices. We will outline the etiology, predisposing factors and the underlying putative mechanisms of DHS, and provide principles and indications for its diagnosis and management. Though desensitization remains to be the first choice for DHS for many dental practitioners and most of desensitizing agents reduce the symptoms of DHS by occluding patent dentinal tubules, the long-term outcome of such treatment is uncertain. With improved understanding of the underlying nociceptive mechanisms of DHS, it is expected that promising novel therapies will emerge and provide more effective relief for patients with DHS.

Modified tension band wiring of patellar fracture as a technique to minimize postoperative complications: A case report.

RATIONALE: Tension band wiring is the most widely accepted technique for the treatment of patellar fractures but the technique is associated with common complications like wire migration, prominence, and breakage. To reduce these complications, we developed and propose a modified technique that has a superior biomechanical strength and a potential to reduce such postoperative complications. PATIENT CONCERNS: The patient presented with pain and mild swelling in his left knee after he slipped on the floor and fell on his left knee. He has no significant past medical or surgical history. The patient took the tension band wiring as the first choice because of the wide acceptance. But he worried about the complications. DIAGNOSES: X-ray showed a transverse fracture of the left patella with an inferior pole occult fracture. INTERVENTIONS: The patient was operated with a modified technique of the classic tension band wiring for patellar fractures. In our 4-step procedure, double tension cerclage wires were wrapped under the exposed ends of the Kirschner wires (K-wires) and the tendons in figure-of-8 fashion. The aim was to increase the biomechanical strength so that when one of the tension wires fail, the other one can hold the fragments together. OUTCOMES: The patient recovered very well and without any complications. The patient was followed-up for 1 year and the fracture has united very well, with satisfying knee range of motion. LESSONS: From this case study, we can detect the biomechanical advantages of our technique which can increase the stability of the fracture and that allows early functional exercise and additionally the micromotion at the fracture site has a beneficial effect of fracture union. Based on the perfect outcomes, our technique is worthy of clinical application.

Screening for potential genes associated with bone overgrowth after mid-shaft femur fracture in a rat model.

BACKGROUND: We investigated the underlying molecular mechanisms of bone overgrowth after femoral fracture by using high-throughput bioinformatics approaches. METHODS: The gene expression profile of GSE3298 (accession number) was obtained from the Gene Expression Omnibus database. Sixteen femoral growth plate samples, including nine samples without fracture and seven fracture samples for seven time points, were used for analysis. The Limma package was applied to identify differentially expressed genes (DEGs) between fractured and intact samples. The DAVID online tool was used for Gene ontology functional and pathway enrichment analysis. A protein-protein interaction (PPI) network established by String software was used to identify interactions between significant DEGs, and network modules were detected using plug-in MCODE. Additionally, a transcription regulatory network was constructed based on the ENCODE Project and PPI network. RESULTS: A total of 680 DEGs were screened in fractured femoral growth plate samples compared with controls, including 238 up- and 442 down-regulated genes. These DEGs were significantly involved in the calcium signaling pathway and cancer pathway. A PPI network was constructed with 167 nodes and 233 edges, and module analysis demonstrated that CCL2, CSF2, NOS2, and DLC1 may stimulate bone overgrowth after femoral fracture via anti-apoptosis-related functions. A transcription regulatory network was constructed with 387 interacting pairs, and overlapping nodes were significantly enriched in intracellular signaling cascade and regulation of cell proliferation, among others. CONCLUSIONS: Bone overgrowth was associated with changes in the expression of identified DEGs such as CCL2, NOS2, CSF2, and DLC1 in the femoral head. They may be important in regulating bone overgrowth via the anti-apoptosis of osteoblasts.

Neuronal NTPDase3 Mediates Extracellular ATP Degradation in Trigeminal Nociceptive Pathway.

ATP induces pain via activation of purinergic receptors in nociceptive sensory nerves. ATP signaling is terminated by ATP hydrolysis mediated by cell surface-localized ecto-nucleotidases. Using enzymatic histochemical staining, we show that ecto-ATPase activity is present in mouse trigeminal nerves. Using immunofluorescence staining, we found that ecto-NTPDase3 is expressed in trigeminal nociceptive neurons and their projections to the brainstem. In addition, ecto-ATPase activity and ecto-NTPDase3 are also detected in the nociceptive outermost layer of the trigeminal subnucleus caudalis. Furthermore, we demonstrate that incubation with anti-NTPDase3 serum reduces extracellular ATP degradation in the nociceptive lamina of both the trigeminal subnucleus caudalis and the spinal cord dorsal horn. These results are consistent with neuronal NTPDase3 activity modulating pain signal transduction and transmission by affecting extracellular ATP hydrolysis within the trigeminal nociceptive pathway. Thus, disruption of trigeminal neuronal NTPDase3 expression and localization to presynaptic terminals during chronic inflammation, local constriction and injury may contribute to the pathogenesis of orofacial neuropathic pain.

Reciprocal interaction between dental alloy biocorrosion and Streptococcus mutans virulent gene expression.

Corrosion of dental alloys is a major concern in dental restorations. Streptococcus mutans reduces the pH in oral cavity and induces demineralization of the enamel as well as corrosion of restorative dental materials. The rough surfaces of dental alloys induced by corrosion enhance the subsequent accumulation of plaque. In this study, the corrosion process of nickel-chromium (Ni-Cr) and cobalt-chromium (Co-Cr) alloys in a nutrient-rich medium containing S. mutans was studied using inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test. Our results showed that the release of Ni and Co ions increased, particularly after incubation for 3 days. The electrochemical corrosion results showed a significant decrease in the corrosion resistance (Rp) value after the alloys were immersed in the media containing S. mutans for 3 days. Correspondingly, XPS revealed a reduction in the relative dominance of Ni, Co, and Cr in the surface oxides after the alloys were immersed in the S. mutans culture. After removal of the biofilm, the pre-corroded alloys were re-incubated in S. mutans medium, and the expressions of genes associated with the adhesion and acidogenesis of S. mutans, including gtfBCD, gbpB, fif and ldh, were evaluated by detecting the mRNA levels using real-time reverse transcription polymerase chain reaction (RT-PCR). We found that the gtfBCD, gbpB, ftf and Idh expression of S. mutans were noticeably increased after incubation with pre-corroded alloys for 24 h. This study demonstrated that S. mutans enhanced the corrosion behavior of the dental alloys, on the other hand, the presence of corroded alloy surfaces up-regulated the virulent gene expression in S. mutans. Compared with smooth surfaces, the rough corroded surfaces of dental alloys accelerated the bacteria-adhesion and corrosion process by changing the virulence gene expression of S. mutans.

Compact surface plasmon resonance imaging sensing system based on general optoelectronic components.

We present a simple surface plasmon resonance imaging (SPRi) sensing system based on some common optoelectronic devices in this paper. Using an optical fiber based SPR sensor as sensing element in our system, the SPRi system is dramatically compact. A small universal LED is used as the light source. The light intensity is record as images that can be captured by a simple web camera. A Microsoft Visual C++6.0 based Windows software program is written to process the image data which contain SPRi information. Experimental results show that the relationship between the relative intensity and RI is a linear relation in a RI range from 1.3396 to 1.3645. Using this SPRi device, we measure the specific binding between the Con A and RNase B, which demonstrates its capability for biomedical selective affinity monitoring. The proposed SPRi sensing system also has the capacity for biochemical multiple channel measurement with further investigation.

Connexin 43 controls the multipolar phase of neuronal migration to the cerebral cortex.

The prospective pyramidal neurons, migrating from the proliferative ventricular zone to the overlaying cortical plate, assume multipolar morphology while passing through the transient subventricular zone. Here, we show that this morphogenetic transformation, from the bipolar to the mutipolar and then back to bipolar again, is associated with expression of connexin 43 (Cx43) and, that knockdown of Cx43 retards, whereas its overexpression enhances, this morphogenetic process. In addition, we have observed that knockdown of Cx43 reduces expression of p27, whereas overexpression of p27 rescues the effect of Cx43 knockdown in the multipolar neurons. Furthermore, functional gap junction/hemichannel domain, and the C-terminal domain of Cx43, independently enhance the expression of p27 and promote the morphological transformation and migration of the multipolar neurons in the SVZ/IZ. Collectively, these results indicate that Cx43 regulates the passage of migrating neurons through their multipolar stage via p27 signaling and that interference with this process, by either genetic and/or environmental factors, may cause cortical malformations.

Both NKCC1 and anion exchangers contribute to Cl⁻ accumulation in postnatal forebrain neuronal progenitors.

Neuronal progenitors are continuously generated in the postnatal rodent subventricular zone and migrate along the rostral migratory stream to supply interneurons in the olfactory bulb. Nonsynaptic GABAergic signaling affects the postnatal neurogenesis by depolarizing neuronal progenitors, which depends on an elevated intracellular Cl(-) concentration. However, the molecular mechanism responsible for Cl(-) accumulation in these cells still remains elusive. Using confocal Ca(2+) imaging, we found that GABA depolarization-induced Ca(2+) increase was either abolished by bumetanide, a specific inhibitor of the Na(+) -K(+) -2Cl(-) cotransporter, or reduced by partial replacement of extracellular Na(+) with Li(+) , in the HEPES buffer but not in the CO(2)/HCO3⁻ buffer. GABA depolarization-induced Ca(2+) increase in CO(2)/HCO3⁻ buffer was abolished by a combination of bumetanide with the anion exchanger inhibitor DIDS or with the carbonic anhydrase inhibitor acetozalimide. Using gramicidin-perforated patch-clamp recording, we further confirmed that bumetanide, together with DIDS or acetozalimide, reduced the intracellular chloride concentration in the neuronal progenitors. In addition, with BrdU labeling, we demonstrated that blocking of the Na(+) -K(+) -2Cl(-) cotransporter, but not anion exchangers, reduced the proliferation of neuronal progenitors. Our results indicate that both the Na(+) -K(+) -2Cl(-) cotransporter and anion exchangers contribute to the elevated intracellular chloride responsible for the depolarizing action of GABA in the postnatal forebrain neuronal progenitors. However, the Na(+) -K(+) -2Cl(-) cotransporter displays an additional effect on neuronal progenitor proliferation.

AMP-activated protein kinase regulates neuronal polarization by interfering with PI 3-kinase localization.

Axon-dendrite polarization is crucial for neural network wiring and information processing in the brain. Polarization begins with the transformation of a single neurite into an axon and its subsequent rapid extension, which requires coordination of cellular energy status to allow for transport of building materials to support axon growth. We found that activation of the energy-sensing adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway suppressed axon initiation and neuronal polarization. Phosphorylation of the kinesin light chain of the Kif5 motor protein by AMPK disrupted the association of the motor with phosphatidylinositol 3-kinase (PI3K), preventing PI3K targeting to the axonal tip and inhibiting polarization and axon growth.

P/Q and N channels control baseline and spike-triggered calcium levels in neocortical axons and synaptic boutons.

Cortical axons contain a diverse range of voltage-activated ion channels, including Ca(2+) currents. Interestingly, Ca(2+) channels are not only located at presynaptic terminals, but also in the axon initial segment (AIS), suggesting a potentially important role in the regulation of action potential generation and neuronal excitability. Here, using two-photon microscopy and whole-cell patch-clamp recording, we examined the properties and role of calcium channels located in the AIS and presynaptic terminals of ferret layer 5 prefrontal cortical pyramidal cells in vitro. Subthreshold depolarization of the soma resulted in an increase in baseline and spike-triggered calcium concentration in both the AIS and nearby synaptic terminals. The increase in baseline calcium concentration rose with depolarization and fell with hyperpolarization with a time constant of approximately 1 s and was blocked by removal of Ca(2+) from the bathing medium. The increases in calcium concentration at the AIS evoked by subthreshold or suprathreshold depolarization of the soma were blocked by the P/Q-channel antagonist omega-agatoxin IVA or the N-channel antagonist omega-conotoxin GVIA or both. The presence of these channels in the AIS pyramidal cells was confirmed with immunochemistry. Block of these channels slowed axonal action potential repolarization, apparently from reduction of the activation of a Ca(2+)-activated K(+) current, and increased neuronal excitability. These results demonstrate novel mechanisms by which calcium currents may control the electrophysiological properties of axonal spike generation and neurotransmitter release in the neocortex.

Gap junctions/hemichannels modulate interkinetic nuclear migration in the forebrain precursors.

During mitotic division in the telencephalic proliferative ventricular zone (VZ), the nuclei of the neural precursors move basally away from the ventricular surface for DNA synthesis, and apically return to the surface for mitotic division; a process known as interkinetic migration or "to-and-fro" nuclear translocation. The cell, which remains attached to the ventricular surface, either continues cycling, or exits the cycle and migrates to the subventricular zone or the developing cortical plate. Although gap junctions/hemichannels are known to modulate DNA synthesis via Ca(2+) waves, the role of Ca(+) oscillations and the mechanism of nuclear translocation in the VZ precursors are unclear. Here, we provide evidence that, during apical nuclear migration, VZ precursors display dynamic spontaneous Ca(2+) transients, which depend on functional gap junctions/hemichannels via ATP release and Ca(2+)-mobilizing messenger diffusion. Furthermore, we found that blocking gap junctions/hemichannels or short hairpin RNA-mediated knockdown of Cx43 (connexin 43) retards the apically directed interkinetic nuclear migration accompanied with changes in the nuclear length/width ratio. In addition, we demonstrated that blocking functional gap junctions/hemichannels induces phosphorylation of small GTPase cdc42 in the VZ precursors. The basal phase of interkinetic migration is much slower and appears to be mediated passively by mechanical forces after cell division. Our findings indicate that functional interference with gap junctions/hemichannels during embryonic development may lead to abnormal corticogenesis and dysfunction of the cerebral cortex in adult organisms.

The role of ATP signaling in the migration of intermediate neuronal progenitors to the neocortical subventricular zone.

Most neurons of the cerebral cortex are generated in the germinal zones near the embryonic cerebral ventricle and migrate radially to the overlying cortical plate. Initially, all dividing cells are attached to the surface of the embryonic ventricle (ventricular zone) until a subset of dividing cells (basal or intermediate neuronal progenitors, INPs), recognized by their immunoreactivity to Tbr2, detach from the ventricular surface and migrate a short distance to establish a secondary proliferative compartment (the subventricular zone). The mechanism that regulates migration of the Tbr2(+) INPs from the ventricular to the subventricular zones is unknown. Here, we show that INPs, unlike the postmitotic neurons that tend to lose the ATP response, continue to express the purinergic P2Y1 receptor. Furthermore, blocking ATP signaling by the P2Y1 blockers, MRS2176, suramin, and apyrase, reduces Ca(2+) transients and retards INP migration to the subventricular zone. In addition, genetic knockdown of the P2Y1 receptor by in vivo application of short hairpin RNA selectively impairs the migration of INPs to the subventricular zone. Together, these results suggest that intercellular ATP signaling is essential for the migration of INPs and the proper formation of the subventricular zone. Interference of ATP signaling or abnormal Ca(2+) fluctuations in INPs may play a significant role in variety of genetic or acquired cortical malformations.

The stumpy gene is required for mammalian ciliogenesis.

Cilia are present on nearly all cell types in mammals and perform remarkably diverse functions. However, the mechanisms underlying ciliogenesis are unclear. Here, we cloned a previously uncharacterized highly conserved gene, stumpy, located on mouse chromosome 7. Stumpy was ubiquitously expressed, and conditional loss in mouse resulted in complete penetrance of perinatal hydrocephalus (HC) and severe polycystic kidney disease (PKD). We found that cilia in stumpy mutant brain and kidney cells were absent or markedly deformed, resulting in defective flow of cerebrospinal fluid. Stumpy colocalized with ciliary basal bodies, physically interacted with gamma-tubulin, and was present along ciliary axonemes, suggesting that stumpy plays a role in ciliary axoneme extension. Therefore, stumpy is essential for ciliogenesis and may be involved in the pathogenesis of human congenital malformations such as HC and PKD.

GFAP-expressing cells in the postnatal subventricular zone display a unique glial phenotype intermediate between radial glia and astrocytes.

Neural stem cells in the adult subventricular zone (SVZ) derive from radial glia and express the astroglial marker glial fibrillary acidic protein (GFAP). Thus, they have been termed astrocytes. However, it remains unknown whether these GFAP-expressing cells express the functional features common to astrocytes. Using immunostaining and patch clamp recordings in acute slices from transgenic mice expressing green fluorescent protein (GFP) driven by the promoter of human GFAP, we show that GFAP-expressing cells in the postnatal SVZ display typical glial properties shared by astrocytes and prenatal radial glia such as lack of action potentials, hyperpolarized resting potentials, gap junction coupling, connexin 43 expression, hemichannels, a passive current profile, and functional glutamate transporters. GFAP-expressing cells express both GLAST and GLT-1 glutamate transporters but lack AMPA-type glutamate receptors as reported for dye-coupled astrocytes. However, they lack 100 microM Ba2+-sensitive inwardly rectifying K+ (K(IR)) currents expressed by astrocytes, but display delayed rectifying K+ currents and 1 mM Ba2+-sensitive K+ currents. These currents contribute to K+ transport at rest and maintain hyperpolarized resting potentials. GFAP-expressing cells stained positive for both K(IR)2.1 and K(IR)4.1 channels, two major K(IR) channels in astrocytes. Ependymal cells, which also derive from radial glia and express GFAP, display typical glial properties and K(IR) currents consistent with their postmitotic nature. Our results suggest that GFAP-expressing cells in concert with ependymal cells can perform typical astrocytic functions such as K+ and glutamate buffering in the postnatal SVZ but display a unique set of functional characteristics intermediate between astrocytes and radial glia.

Kallidin-like peptide mediates the cardioprotective effect of the ACE inhibitor captopril against ischaemic reperfusion injury of rat heart.

1. The potential cardioprotective effect of ACE inhibitors has been attributed to the inhibition of bradykinin degradation. Recent data in rats documented a kallidin-like peptide, which mimics the cardioprotective effect of ischaemic preconditioning. This study investigates in isolated Langendorff rat heart the effect of the ACE inhibitor captopril, the role of bradykinin, kallidin-like peptide, and nitric oxide (NO). 2. The bradykinin level in the effluent of the control group was 14.6 pg ml(-1) and was not affected by captopril in the presence or absence of kinin B2-receptor antagonist, HOE140. 3. The kallidin-like peptide levels were approximately six-fold higher (89.8 pg ml(-1)) and increased significantly by treatment with captopril (144 pg ml(-1)), and simultaneous treatment with captopril and HOE140 (197 pg ml(-1)). 4. Following 30 min ischaemia in the control group, the creatine kinase activity increased from 0.4 to 53.4 U l(-1). In the captopril group and in the captopril+L-NAME group, the creatine kinase activity was significantly lower (18.5 and 22.8 U l(-1)). This beneficial effect of captopril was completely abolished by the kinin B2-receptor antagonist, HOE140, as well as by the kallidin antiserum. 5. Perfusion of the hearts with kallidin before the 30 min ischaemia, but not with bradykinin, yielded an approximately 50% reduction in creatine kinase activity after reperfusion. 6. Pretreatment with L-NAME alone and simultaneously with captopril, and with kallidin, respectively, suggests a kinin-independent action of NO before the 30 min ischaemia on coronary flow and a kinin-dependent action after ischaemia. 7. These data show that captopril increases kallidin-like peptide in the effluent. Kallidin-like peptide via kinin B2 receptor seems to be the physiological mediator of cardioprotective actions of captopril against ischaemic reperfusion injury. HOE140 as well as the kallidin antiserum abolished the cardioprotective effects of captopril.

A kallidin-like peptide is a protective cardiac kinin, released by ischaemic preconditioning of rat heart.

Bradykinin is thought to play a major role among the endogenous cardioprotective candidates of ischaemic preconditioning (IPC). Little attention has been paid to the fact that in the tissue kallidin (KAL), rather than bradykinin might be the physiological mediator of the kallikrein-kinin system. In order to evaluate the importance of one or the other peptide the release and effect of both kinins has been investigated in isolated rat hearts following IPC. Bradykinin- and a KAL-like peptide were measured in the effluent of the rat isolated Langendorff heart with two different specific radioimmunoassays. The creatine kinase activity in the effluent was judged as degree of cardiac injury caused by ischaemia. During IPC, which consists of three 5 min no-flow and 5 min reperfusion cycles prior to the 30 min ischaemia, the bradykinin level in the effluent did not change significantly (15.4-19.4 pg ml(-1)). In the control group the bradykinin levels were 15.9-16.6 pg ml(-1). During IPC KAL-like peptide (Arg(1)-, instead of Lys(1)-KAL), which has recently been verified by mass spectrometry, displays 5.8-fold higher levels in the effluent and significantly increases in the same time interval from 90.4 to 189 pg ml(-1). After 30 min ischaemia the bradykinin levels in the IPC group were not significantly different to those of the control group (18.7 vs 14.4 pg ml(-1)). The KAL-like peptide levels in the IPC group vs the control group were 105 vs 86.1 pg ml(-1). By the 30 min ischaemia the creatine kinase activity in the IPC group increased from 0.367 to 8.93 U l(-1) (before and 10-30 min after ischaemia). In the control group during the same time period the creatine kinase levels increased from 0.277 to 34.9 U l(-1). The low increase in creatine kinase activity following IPC was taken as equivalent of the cardioprotective action. A KAL antibody or HOE140 (kinin B(2)-receptor antagonist) completely abolished this beneficial effect of IPC (36.6 and 53.0 U l(-1)) when added to the perfusion medium during the reperfusion cycles of IPC prior to the 30 min ischaemia. Our data suggest that in rat hearts KAL-like peptide rather than bradykinin is the physiological compound activated by IPC and acting via the cardiac kinin B(2)-receptor. Thus, endogenously generated KAL-like peptide seems to play a major role in the cardioprotection of IPC.

Nonsynaptic GABA signaling in postnatal subventricular zone controls proliferation of GFAP-expressing progenitors.

In the postnatal subventricular zone (SVZ), local cues or signaling molecules released from neuroblasts limit the proliferation of glial fibrillary acidic protein (GFAP)-expressing progenitors thought to be stem cells. However, signals between SVZ cells have not been identified. We show that depolarization of neuroblasts induces nonsynaptic SNARE-independent GABA(A) receptor currents in GFAP-expressing cells, the time course of which depends on GABA uptake in acute mouse slices. We found that GABA(A) receptors are tonically activated in GFAP-expressing cells, consistent with the presence of spontaneous depolarizations in neuroblasts that are sufficient to induce GABA release. These data demonstrate the existence of nonsynaptic GABAergic signaling between neuroblasts and GFAP-expressing cells. Furthermore, we show that GABA(A) receptor activation in GFAP-expressing cells limits their progression through the cell cycle. Thus, as GFAP-expressing cells generate neuroblasts, GABA released from neuroblasts provides a feedback mechanism to control the proliferation of GFAP-expressing progenitors by activating GABA(A) receptors.