RESUMEN
Regeneration is the remarkable phenomenon through which an organism can regrow lost or damaged parts with fully functional replacements, including complex anatomical structures, such as limbs. In 2019, Development launched its 'Model systems for regeneration' collection, a series of articles introducing some of the most popular model organisms for studying regeneration in vivo. To expand this topic further, this Perspective conveys the voices of five expert biologists from the field of regenerative biology, each of whom showcases some less well-known, but equally extraordinary, species for studying regeneration.
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Regeneración , Animales , Humanos , Extremidades/fisiología , Modelos Biológicos , Regeneración/fisiologíaRESUMEN
Blastema formation is a crucial process that provides a cellular source for regenerating tissues and organs. While bilaterians have diversified blastema formation methods, its mechanisms in non-bilaterians remain poorly understood. Cnidarian jellyfish, or medusae, represent early-branching metazoans that exhibit complex morphology and possess defined appendage structures highlighted by tentacles with stinging cells (nematocytes). Here, we investigate the mechanisms of tentacle regeneration, using the hydrozoan jellyfish Cladonema pacificum. We show that proliferative cells accumulate at the tentacle amputation site and form a blastema composed of cells with stem cell morphology. Nucleoside pulse-chase experiments indicate that most repair-specific proliferative cells (RSPCs) in the blastema are distinct from resident stem cells. We further demonstrate that resident stem cells control nematogenesis and tentacle elongation during both homeostasis and regeneration as homeostatic stem cells, while RSPCs preferentially differentiate into epithelial cells in the newly formed tentacle, analogous to lineage-restricted stem/progenitor cells observed in salamander limbs. Taken together, our findings propose a regeneration mechanism that utilizes both resident homeostatic stem cells (RHSCs) and RSPCs, which in conjunction efficiently enable functional appendage regeneration, and provide novel insight into the diversification of blastema formation across animal evolution.
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Hidrozoos , Animales , Células Madre , Células EpitelialesRESUMEN
BACKGROUND: The remarkable regenerative abilities observed in planarians and cnidarians are closely linked to the active proliferation of adult stem cells and the precise differentiation of their progeny, both of which typically deteriorate during aging in low regenerative animals. While regeneration-specific genes conserved in highly regenerative organisms may confer regenerative abilities and long-term maintenance of tissue homeostasis, it remains unclear whether introducing these regenerative genes into low regenerative animals can improve their regeneration and aging processes. RESULTS: Here, we ectopically express highly regenerative species-specific JmjC domain-encoding genes (HRJDs) in Drosophila, a widely used low regenerative model organism. Surprisingly, HRJD expression impedes tissue regeneration in the developing wing disc but extends organismal lifespan when expressed in the intestinal stem cell lineages of the adult midgut under non-regenerative conditions. Notably, HRJDs enhance the proliferative activity of intestinal stem cells while maintaining their differentiation fidelity, ameliorating age-related decline in gut barrier functions. CONCLUSIONS: These findings together suggest that the introduction of highly regenerative species-specific genes can improve stem cell functions and promote a healthy lifespan when expressed in aging animals.
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Regeneración , Animales , Regeneración/genética , Regeneración/fisiología , Envejecimiento/genética , Envejecimiento/fisiología , Especificidad de la Especie , Drosophila/genética , Drosophila/fisiología , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/fisiología , Drosophila melanogaster/crecimiento & desarrollo , Células Madre/metabolismo , Intestinos/fisiología , Diferenciación Celular/genética , Proliferación CelularRESUMEN
Giant viruses are remarkable for their large genomes, often rivaling those of small bacteria, and for having genes thought exclusive to cellular life. Most isolated to date infect nonmarine protists, leaving their strategies and prevalence in marine environments largely unknown. Using eukaryotic single-cell metagenomics in the Pacific, we discovered a Mimiviridae lineage of giant viruses, which infects choanoflagellates, widespread protistan predators related to metazoans. The ChoanoVirus genomes are the largest yet from pelagic ecosystems, with 442 of 862 predicted proteins lacking known homologs. They are enriched in enzymes for modifying organic compounds, including degradation of chitin, an abundant polysaccharide in oceans, and they encode 3 divergent type-1 rhodopsins (VirR) with distinct evolutionary histories from those that capture sunlight in cellular organisms. One (VirRDTS) is similar to the only other putative rhodopsin from a virus (PgV) with a known host (a marine alga). Unlike the algal virus, ChoanoViruses encode the entire pigment biosynthesis pathway and cleavage enzyme for producing the required chromophore, retinal. We demonstrate that the rhodopsin shared by ChoanoViruses and PgV binds retinal and pumps protons. Moreover, our 1.65-Å resolved VirRDTS crystal structure and mutational analyses exposed differences from previously characterized type-1 rhodopsins, all of which come from cellular organisms. Multiple VirR types are present in metagenomes from across surface oceans, where they are correlated with and nearly as abundant as a canonical marker gene from Mimiviridae Our findings indicate that light-dependent energy transfer systems are likely common components of giant viruses of photosynthetic and phagotrophic unicellular marine eukaryotes.
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Evolución Biológica , Eucariontes/virología , Virus Gigantes/genética , Phycodnaviridae/genética , Rodopsina/metabolismo , Agua de Mar/virología , Proteínas Virales/metabolismo , Ecosistema , Genoma Viral , Virus Gigantes/clasificación , Metagenómica , Océanos y Mares , Phycodnaviridae/clasificación , Filogenia , Protones , Rodopsina/química , Rodopsina/genética , Proteínas Virales/química , Proteínas Virales/genéticaRESUMEN
Many microorganisms express rhodopsins, pigmented membrane proteins capable of absorbing sunlight and harnessing that energy for important biological functions such as ATP synthesis and phototaxis. Microbial rhodopsins that have been discovered to date are categorized as type-1 rhodopsins. Interestingly, researchers have very recently unveiled a new microbial rhodopsin family named the heliorhodopsins, which are phylogenetically distant from type-1 rhodopsins. Among them, only heliorhodopsin-48C12 (HeR-48C12) from a Gram-positive eubacterium has been photochemically characterized [Pushkarev, A., et al. (2018) Nature 558, 595-599]. In this study, we photochemically characterize a purple-colored heliorhodopsin from Gram-negative eubacterium Bellilinea caldifistulae (BcHeR) as a second example and identify which properties are or are not conserved between BcHeR and HeR-48C12. A series of photochemical measurements revealed several conserved properties between them, including a visible absorption spectrum with a maximum at around 550 nm, the lack of ion-transport activity, and the existence of a second-order O-like intermediate during the photocycle that may activate an unidentified biological function. In contrast, as a property that is not conserved, although HeR-48C12 shows the light adaptation state of retinal, BcHeR showed the same retinal configuration under both dark- and light-adapted conditions. These comparisons of photochemical properties between BcHeR and HeR-48C12 are an important first step toward understanding the nature and functional role of heliorhodopsins.
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Proteínas Bacterianas/química , Chloroflexi/química , Rodopsinas Microbianas/química , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Chloroflexi/genética , Bacterias Gramnegativas/química , Bacterias Gramnegativas/genética , Luz , Procesos Fotoquímicos , Filogenia , Rodopsinas Microbianas/genéticaRESUMEN
During epithelial cell proliferation, planar alignment of the mitotic spindle coordinates the local process of symmetric cell cleavage with the global maintenance of polarized tissue architecture. Although the disruption of planar spindle alignment is proposed to cause epithelial to mesenchymal transition and cancer, the in vivo mechanisms regulating mitotic spindle orientation remain elusive. Here we demonstrate that the actomyosin cortex and the junction-localized neoplastic tumour suppressors Scribbled and Discs large 1 have essential roles in planar spindle alignment and thus the control of epithelial integrity in the Drosophila imaginal disc. We show that defective alignment of the mitotic spindle correlates with cell delamination and apoptotic death, and that blocking the death of misaligned cells is sufficient to drive the formation of basally localized tumour-like masses. These findings indicate a key role for junction-mediated spindle alignment in the maintenance of epithelial integrity, and also reveal a previously unknown cell-death-mediated tumour-suppressor function inherent in the polarized architecture of epithelia.
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Drosophila/citología , Drosophila/metabolismo , Células Epiteliales/metabolismo , Uniones Intercelulares/metabolismo , Huso Acromático/metabolismo , Actinas/genética , Actinas/metabolismo , Animales , Drosophila/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Células Epiteliales/citología , Regulación del Desarrollo de la Expresión Génica , Huso Acromático/genéticaRESUMEN
A novel Gram-negative bacterium, designated 4G11T, was isolated from the sea surface microlayer of a marine inlet. On the basis of 16S rRNA gene sequence analysis, the strain showed the closest similarity to Amylibacter ulvae KCTC 32465T (99.0â%). However, DNA-DNA hybridization values showed low DNA relatedness between strain 4G11T and its close phylogenetic neighbours, Amylibacter marinus NBRC 110140T (8.0±0.4â%) and Amylibacter ulvae KCTC 32465T (52.9±0.9â%). Strain 4G11T had C18â:â1, C16â:â0 and C18â:â2 as the major fatty acids. The only isoprenoid quinone detected for strain 4G11T was ubiquinone-10. The major polar lipids were phosphatidylglycerol, phosphatidylcholine, one unidentified polar lipid, one unidentified phospholipid and one unidentified aminolipid. The DNA G+C content of strain 4G11T was 50.0 mol%. Based on phenotypic and chemotaxonomic characteristics and analysis of the 16S rRNA gene sequence, the novel strain should be assigned to a novel species, for which the name Amylibacter kogurei sp. nov. is proposed. The type strain of Amylibacter kogurei is 4G11T (KY463497=KCTC 52506T=NBRC 112428T).
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Filogenia , Rhodobacteraceae/clasificación , Agua de Mar/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , Bahías , ADN Bacteriano/genética , Ácidos Grasos/química , Japón , Hibridación de Ácido Nucleico , Fosfolípidos/química , ARN Ribosómico 16S/genética , Rhodobacteraceae/genética , Rhodobacteraceae/aislamiento & purificación , Análisis de Secuencia de ADN , Ubiquinona/químicaRESUMEN
A new group of microbial rhodopsins named xenorhodopsins (XeR), which are closely related to the cyanobacterial Anabaena sensory rhodopsin, show a light-driven "inward" proton transport activity, as reported for one representative of this group from Parvularcula oceani (PoXeR). In this study, we functionally and spectroscopically characterized a new member of the XeR clade from a marine bacterium Rubricoccus marinus SG-29T (RmXeR). Escherichia coli cells expressing recombinant RmXeR showed a light-induced alkalization of the cell suspension, which was strongly impaired by a protonophore, suggesting that RmXeR is a light-driven "inward" proton pump as is PoXeR. The spectroscopic properties of purified RmXeR were investigated and compared with those of PoXeR and a light-driven "outward" proton pump, bacteriorhodopsin (BR) from the archaeon Halobacterium salinarum. Action spectroscopy revealed that RmXeR with all-trans retinal is responsible for the light-driven inward proton transport activity, but not with 13-cis retinal. From pH titration experiments and mutational analysis, we estimated the pKa values for the protonated Schiff base of the retinal chromophore and its counterion as 11.1 ± 0.07 and 2.1 ± 0.07, respectively. Of note, the direction of both the retinal composition change upon light-dark adaptation and the acid-induced spectral shift was opposite that of BR, which is presumably related to the opposite directions of ion transport (from outside to inside for RmXeR and from inside to outside for BR). Flash photolysis experiments revealed the appearances of three intermediates (L, M and O) during the photocycle. The proton uptake and release were coincident with the formation and decay of the M intermediate, respectively. Together with associated findings from other microbial rhodopsins, we propose a putative model for the inward proton transport mechanism of RmXeR.
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Rodopsinas Microbianas/metabolismo , Secuencia de Aminoácidos , Proteínas Arqueales/química , Proteínas Arqueales/metabolismo , Bacteriorodopsinas/química , Bacteriorodopsinas/metabolismo , Escherichia coli , Halobacterium/metabolismo , Concentración de Iones de Hidrógeno , Transporte Iónico/efectos de la radiación , Luz , Filogenia , Protones , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Retinaldehído/química , Retinaldehído/metabolismo , Rodopsinas Microbianas/clasificación , Rodopsinas Microbianas/genética , Rhodothermus , Bases de Schiff/química , Bases de Schiff/metabolismo , EspectrofotometríaRESUMEN
The light-driven inward chloride ion-pumping rhodopsin Nonlabens marinus rhodopsin-3 (NM-R3), from a marine flavobacterium, belongs to a phylogenetic lineage distinct from the halorhodopsins known as archaeal inward chloride ion-pumping rhodopsins. NM-R3 and halorhodopsin have distinct motif sequences that are important for chloride ion binding and transport. In this study, we present the crystal structure of a new type of light-driven chloride ion pump, NM-R3, at 1.58 Å resolution. The structure revealed the chloride ion translocation pathway and showed that a single chloride ion resides near the Schiff base. The overall structure, chloride ion-binding site, and translocation pathway of NM-R3 are different from those of halorhodopsin. Unexpectedly, this NM-R3 structure is similar to the crystal structure of the light-driven outward sodium ion pump, Krokinobacter eikastus rhodopsin 2. Structural and mutational analyses of NM-R3 revealed that most of the important amino acid residues for chloride ion pumping exist in the ion influx region, located on the extracellular side of NM-R3. In contrast, on the opposite side, the cytoplasmic regions of K. eikastus rhodopsin 2 were reportedly important for sodium ion pumping. These results provide new insight into ion selection mechanisms in ion pumping rhodopsins, in which the ion influx regions of both the inward and outward pumps are important for their ion selectivities.
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Proteínas Bacterianas/química , Canales de Cloruro/química , Flavobacteriaceae/química , Halorrodopsinas/química , Luz , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Canales de Cloruro/genética , Canales de Cloruro/metabolismo , Cristalografía por Rayos X , Flavobacteriaceae/genética , Flavobacteriaceae/metabolismo , Halorrodopsinas/genética , Halorrodopsinas/metabolismo , Dominios Proteicos , Relación Estructura-ActividadRESUMEN
In organisms, ion transporters play essential roles in the generation and dissipation of ion gradients across cell membranes. Microbial rhodopsins selectively transport cognate ions using solar energy, in which the substrate ions identified to date have been confined to monovalent ions such as H+, Na+, and Cl-. Here we report a novel rhodopsin from the cyanobacterium Synechocystis sp. PCC 7509, which inwardly transports a polyatomic divalent sulfate ion, SO42-, with changes of its spectroscopic properties in both unphotolyzed and photolyzed states. Upon illumination, cells expressing the novel rhodopsin, named Synechocystis halorhodopsin (SyHR), showed alkalization of the medium only in the presence of Cl- or SO42-. That alkalization signal was enhanced by addition of a protonophore, indicating an inward transport of Cl- and SO42- with a subsequent secondary inward H+ movement across the membrane. The anion binding to SyHR was suggested by absorption spectral shifts from 542 to 536 nm for Cl- and from 542 to 556 nm for SO42-, and the affinities of Cl- and SO42- were estimated as 0.112 and 5.81 mM, respectively. We then performed time-resolved spectroscopic measurements ranging from femtosecond to millisecond time domains to elucidate the structure and structural changes of SyHR during the photoreaction. Based on the results, we propose a photocycle model for SyHR in the absence or presence of substrate ions with the timing of their uptake and release. Thus, we demonstrate SyHR as the first light-driven polyatomic divalent anion (SO42-) transporter and report its spectroscopic characteristics.
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Luz , Rodopsinas Microbianas/metabolismo , Sulfatos/metabolismo , Synechocystis/química , Aniones/química , Aniones/metabolismo , Rodopsinas Microbianas/química , Espectrofotometría Ultravioleta , Sulfatos/química , Synechocystis/metabolismoRESUMEN
Apoptosis is one of the cell-intrinsic suicide programs and is an essential cellular behavior for animal development and homeostasis. Traditionally, apoptosis has been regarded as a cell-autonomous phenomenon. However, recent in vivo genetic studies have revealed that apoptotic cells actively influence the behaviors of surrounding cells, including engulfment, proliferation, and production of mechanical forces. Such interactions can be bidirectional, and apoptosis is non-autonomously induced in a cellular community. Of note, it is becoming evident that active communication between apoptotic cells and living cells contributes to physiological processes during tissue remodeling, regeneration, and morphogenesis. In this review, we focus on the mutual interactions between apoptotic cells and their neighbors in cellular society and discuss issues relevant to future studies of apoptosis.
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Apoptosis/fisiología , Comunicación Celular/fisiología , Drosophila melanogaster/fisiología , Fagocitosis/fisiología , Transducción de Señal/fisiología , Animales , Apoptosis/genética , Proliferación Celular/fisiología , Macrófagos/inmunología , Macrófagos/fisiología , Morfogénesis/fisiología , Regeneración/fisiologíaRESUMEN
Two types of disruptive effects of irrelevant sound on visual tasks have been reported: the changing-state effect and the deviation effect. The idea that the deviation effect, which arises from attentional capture, is independent of task requirements, whereas the changing-state effect is specific to tasks that require serial processing, has been examined by comparing tasks that do or do not require serial-order processing. While many previous studies used the missing-item task as the nonserial task, it is unclear whether other cognitive tasks lead to similar results regarding the different task specificity of both effects. Kattner et al. (Memory and Cognition, 2023) used the mental-arithmetic task as the nonserial task, and failed to demonstrate the deviation effect. However, there were several procedural factors that could account for the lack of deviation effect, such as differences in design and procedures (e.g., conducted online, intermixed conditions). In the present study, we aimed to investigate whether the deviation effect could be observed in both the serial-recall and mental-arithmetic tasks when these procedural factors were modified. We found strong evidence of the deviation effect in both the serial-recall and the mental-arithmetic tasks when stimulus presentation and experimental design were aligned with previous studies that demonstrated the deviation effect (e.g., conducted in-person, blockwise presentation of sound, etc.). The results support the idea that the deviation effect is not task-specific.
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Estimulación Acústica , Atención , Percepción Auditiva , Humanos , Femenino , Atención/fisiología , Masculino , Adulto Joven , Percepción Auditiva/fisiología , Adulto , Recuerdo Mental/fisiología , Sonido , Tiempo de Reacción/fisiología , Percepción Visual/fisiologíaRESUMEN
Purpose: To evaluate the safety, pharmacokinetics, and exploratory efficacy of tivozanib eye drops in healthy volunteers and patients with neovascular age-related macular degeneration (nAMD). Design: This multicenter group-sequential dose escalation phase I study consisted of a placebo-controlled double-masked study of healthy volunteers (cohorts 1 and 2) and an open-label study of patients with nAMD (cohort 3). Participants: Healthy volunteers: Japanese or White men aged 20 to <50 years. Patients with nAMD with central subfield thickness (CST) ≥300 µm and best-corrected visual acuity score ≥23 letters in the study eye. Methods: In the single-dose cohort of healthy men (cohort 1: steps 1-5), 1 or 2 tivozanib eye drops (30 µL/drop, 5-minute interval; 0.5, 1.0, and 2.0 w/v%) or placebo were administered in 1 eye once. In the multiple-dose cohort of healthy men (cohort 2: steps 1-6), 1 or 2 tivozanib eye drops (0.5, 1.0, and 2.0 w/v%) or placebo were administered 3 times daily in 1 eye for 21 days. In the multiple-dose cohort of patients with nAMD (cohort 3, steps 1-3), 1 or 2 tivozanib eye drops (0.5 and 1.0 w/v%) were administered 3 times daily in 1 affected eye for 21 days. Main Outcome Measures: The safety outcome measures included adverse events (AEs). The pharmacokinetic outcome was serum tivozanib concentration. Among the exploratory efficacy outcomes, CST was evaluated. Results: In total, 40, 48, and 28 participants were enrolled in cohorts 1, 2, and 3, respectively. Serious AEs did not occur in cohorts 1 to 3. The most frequent AE in multiple-dose cohorts was reversible punctate keratitis: placebo arm, 8.3% (healthy men, 1/12); tivozanib arm, 47.2% (healthy men, 17/36) and 14.3% (nAMD, 4/28). Serum tivozanib exposure increased dose-dependently and was similar in healthy men and patients with nAMD. In patients with nAMD, mean CST changes from baseline to day 22 were -27.6 ± 54.88 (0.5 w/v%; 1 drop, 3 times daily), -35.6 ± 49.64 (1.0 w/v%; 1 drop, 3 times daily), and -43.7 ± 55.19 µm (1.0 w/v%; 2 drops, 3 times daily). Conclusions: Tivozanib eye drops showed a favorable safety profile in healthy Japanese and White men and Japanese patients with nAMD. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Here, we present the draft genome sequences of three Croceitalea sp. strains containing microbial rhodopsins, isolated from the Japanese coastal sea surface microlayer, which is exposed to intense sunlight. This study will contribute to the understanding of the genus Croceitalea and the diversity of microbial rhodopsins.
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We previously published an investigation indicating freeze-dried platelet-rich plasma (PRP)-coated polyglactin mesh was a promising wound-dressing material. However, one of its disadvantages was the inflammatory nature due to degradation of the polyglactin. Therefore, in this study, we investigated the use of a collagen sponge as the carrier for PRP. When implanted subcutaneously in nude mice, the PRP-coated sponge alone rapidly induced angiogenesis and infiltration of surrounding connective tissue without inducing appreciable inflammation. Moreover, addition of periosteal fibroblastic cells substantially augmented the angiogenic response. With in vitro studies, the PRP-coated sponge provided various major growth factors at high levels to stimulate the proliferation of cells cultured on plastic dishes, but did not stimulate the proliferation of cells inoculated into the PRP-coated sponge. Cells were embedded in the fibrin mesh and maintained their spherical shape without stretching. The atomic force microscopic analysis demonstrated that the fibrin gel formed on the PRP-coated sponge was much softer (approx. 22 kPa) than the cross-linked collagen that formed the sponge base (appox. 1.9 MPa). Because insoluble matrices have recently and increasingly been considered important regulatory factors of cellular behavior, as are soluble growth factors, it is suggested that this soft fibrin mesh possibly suppresses cell survival. Overall, our investigation has successfully demonstrated improved wound-healing and regenerative potential of the PRP-coated mesh by combining it with the collagen sponge. In the clinical setting, this PRP-coated collagen sponge is a promising material for connective tissue regenerative therapy, such as periodontal therapy, burn victim treatment and in cosmetic or plastic surgery.
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Colágeno/química , Liofilización , Péptidos y Proteínas de Señalización Intercelular/administración & dosificación , Periostio/citología , Plasma Rico en Plaquetas/metabolismo , Andamios del Tejido/química , Animales , Materiales Biocompatibles/química , Células Cultivadas , Colágeno/ultraestructura , Elasticidad , Fibrina/química , Fibrina/ultraestructura , Fibroblastos/citología , Fibroblastos/trasplante , Humanos , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Cicatrización de HeridasRESUMEN
Patient-derived xenograft (PDX) is an emerging tool established in immunodeficient vertebrate models to assess individualized treatments for cancer patients. Current xenograft models are deficient in adaptive immune systems. However, the precise role of the innate immunity in the xenograft models is unknown. With conserved signaling pathways and established genetic tools, Drosophila has contributed to the understanding of the mechanism of tumor growth as well as tumor-host interactions for decades, making it a promising candidate model for studying whether or not the hosts' innate immunity can accommodate transplanted human tumor cells. Here we show initial observations that assess the behavior and impact of several human tumor cell lines when transplanted into Drosophila. We found that some injected cell lines persisted for a longer duration and reduced hosts' lifespan. In particular, the human lung cancer cell line A549 were observed adjacent to the fly host tissues. We examined two factors that affect the survivability of cancer cells: (1) the optimal temperature of each cell line and (2) the innate immunity of Drosophila hosts. Especially, transplanted human tumor cells survived longer in immunodeficient flies, suggesting that the host innate immune system impedes the growth of xenografted cells. Our attempts for xenografting fly models thus provide necessary steps to overcome for establishing PDX cancer models using invertebrates.
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Drosophila , Inmunidad Innata , Animales , Humanos , Drosophila/genética , Trasplante Heterólogo , Xenoinjertos , Modelos Animales de Enfermedad , Línea Celular Tumoral , MamíferosRESUMEN
Background: In patients with Parkinson's Disease (PD), two distinct motor subtypes, tremor dominant (TD) and postural instability and gait difficulty (PIGD), can be differentiated using Unified Parkinson's Disease Rating Scale (UPDRS) sub-scores. This post hoc analysis of pooled data from eight pivotal studies examined the effect of treatment with istradefylline, a selective adenosine A2A receptor antagonist, on these subtypes. Methods: In eight randomized, placebo-controlled phase 2b/3 trials, patients on levodopa with carbidopa/benserazide experiencing motor complications received istradefylline (20 or 40 mg/day) or placebo for 12 or 16 weeks. TD subtype was defined by the UPDRS II/III items kinetic and postural tremor in right/left hand and (resting) tremor in the face, lips, chin, hands, or feet; PIGD items were freezing, walking, posture, gait, and postural instability. The ratio of mean scores from TD:PIGD items determined subtype (TD [TD:PIGD ratio ≥ 1.5], PIGD [TD:PIGD ratio ≤ 1.0], mixed-type [ratio 1-1.5]). Results: In total, 2719 patients were included (PIGD, n = 2165; TD, n = 118; mixed-type, n = 188; not evaluable, n = 248). Among TD subtype patients, the least-squares mean change from baseline versus placebo in UPDRS II/III TD-related total score was significant at 20 mg/day istradefylline (-2.21; 95 % CI, -4.05 to -0.36; p = 0.02). For PIGD subtype patients, there was a significant difference from placebo in UPDRS II/III PIGD-related total score at 40 mg/day istradefylline (-0.25; -0.43 to -0.06; p = 0.01). Conclusions: The data from this analysis of UPDRS-based motor subtypes suggest that istradefylline can improve motor disability in PD patients with motor fluctuations regardless of PD subtype. Future research should characterize the effects of istradefylline on tremor.
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Owing to the necessity for the immediate preparation from patients' blood, autologous platelet-rich plasma (PRP) limits its clinical applicability. To address this concern and respond to emergency care and other unpredictable uses, we have developed a freeze-dried PRP in an adsorbed form on a biodegradable polymer material (Polyglactin 910). On the polymer filaments of PRP mesh, which was prepared by coating the polymer mesh with human fresh PRP and subsequent freeze-drying, platelets were incorporated, and related growth factors were preserved at high levels. This new PRP mesh preparation significantly and reproducibly stimulated the proliferation of human periodontal ligament cells in vitro and neovascularization in a chorioallantoic membrane assay. A full-thickness skin defect model in a diabetic mouse demonstrated the PRP mesh, although prepared from human blood, substantially facilitated angiogenesis, granulation tissue formation, and re-epithelialization without inducing severe inflammation in vivo. These data demonstrate that our new PRP mesh preparation functions as a bioactive material to facilitate tissue repair/regeneration. Therefore, we suggest that this bioactive material, composed of allogeneic PRP, could be clinically used as a promising alternative in emergency care or at times when autologous PRP is not prepared immediately before application.
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Plaquetas/fisiología , Membrana Corioalantoides/irrigación sanguínea , Plasma Rico en Plaquetas/química , Piel/irrigación sanguínea , Mallas Quirúrgicas , Cicatrización de Heridas/efectos de los fármacos , Adsorción , Animales , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Proliferación Celular/efectos de los fármacos , Embrión de Pollo , Membrana Corioalantoides/efectos de los fármacos , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Liofilización , Tejido de Granulación/efectos de los fármacos , Humanos , Ratones , Neovascularización Fisiológica , Ligamento Periodontal/efectos de los fármacos , Ligamento Periodontal/patología , Recuento de Plaquetas , Poliglactina 910/química , Poliglactina 910/farmacología , Piel/lesionesRESUMEN
Adult tissues in Metazoa dynamically remodel their structures in response to environmental challenges including sudden injury, pathogen infection, and nutritional fluctuation, while maintaining quiescence under homoeostatic conditions. This characteristic, hereafter referred to as adult tissue plasticity, can prevent tissue dysfunction and improve the fitness of organisms in continuous and/or severe change of environments. With its relatively simple tissue structures and genetic tools, studies using the fruit fly Drosophila melanogaster have provided insights into molecular mechanisms that control cellular responses, particularly during regeneration and nutrient adaptation. In this review, we present the current understanding of cellular mechanisms, stem cell proliferation, polyploidization, and cell fate plasticity, all of which enable adult tissue plasticity in various Drosophila adult organs including the midgut, the brain, and the gonad, and discuss the organismal strategy in response to environmental changes and future directions of the research.
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Drosophila melanogaster , Drosophila , Adaptación Fisiológica , Animales , Diferenciación Celular , Drosophila/fisiología , Drosophila melanogaster/genética , Homeostasis/fisiologíaRESUMEN
Cnidarians, including sea anemones, corals, and jellyfish, exhibit diverse morphology and lifestyles that are manifested in sessile polyps and free-swimming medusae. As exemplified in established models such as Hydra and Nematostella, stem cells and/or proliferative cells contribute to the development and regeneration of cnidarian polyps. However, the underlying cellular mechanisms in most jellyfish, particularly at the medusa stage, are largely unclear, and, thus, developing a robust method for identifying specific cell types is critical. This paper describes a protocol for visualizing stem-like proliferating cells in the hydrozoan jellyfish Cladonema pacificum. Cladonema medusae possess branched tentacles that continuously grow and maintain regenerative capacity throughout their adult stage, providing a unique platform with which to study the cellular mechanisms orchestrated by proliferating and/or stem-like cells. Whole-mount fluorescent in situ hybridization (FISH) using a stem cell marker allows for the detection of stem-like cells, while pulse labeling with 5-ethynyl-2'-deoxyuridine (EdU), an S phase marker, enables the identification of proliferating cells. Combining both FISH and EdU labeling, we can detect actively proliferating stem-like cells on fixed animals, and this technique can be broadly applied to other animals, including non-model jellyfish species.