Expression analysis of Hsp90α and cytokines in zebrafish caudal fin regeneration

Growth patterns of caudal fin rays are informed by both external signals from the regenerating organ and remembered identity autonomous to the local tissue

Regenerating tissues must remember or interpret their spatial position, using this information to restore original size and patterning. The external skeleton of the zebrafish caudal fin is composed of 18 rays; after any portion of the fin is amputated, position-dependent regenerative growth restores each ray to its original length. We tested for transcriptional differences during regeneration of proximal versus distal tissues and identified 489 genes that differed in proximodistal expression. Thyroid hormone directs multiple aspects of ray patterning along the proximodistal axis, and we identified 364 transcripts showing a proximodistal expression pattern that was dependent on thyroid hormone context. To test what aspects of ray positional identity are directed by extrinsic environental cues versus remembered identity autonomous to the tissue, we transplanted distal portions of rays to proximal environments and evaluated regeneration within the new location. Native regenerating proximal tissue showed robust expression of scpp7, a transcript with thyroid-regulated proximal enrichment; in contrast, regenerating rays originating from transplanted distal tissue showed reduced (distal-like) expression during outgrowth. These distal-to-proximal transplants regenerated far beyond the length of the graft itself, indicating that cues from the proximal environment promoted additional growth. Nonetheless, these transplants initiated regeneration at a much slower rate compared to controls, suggesting memory of distal identity was retained by the transplanted tissue. This early growth retardation caused rays that originated from transplants to grow noticeably shorter than neighboring native rays. While several aspects of fin ray morphology (bifurcation, segment length) were found to be determined by the environment, we found that both regeneration speed and ray length are remembered autonomously by tissues, and that persist through multiple rounds of amputation and regeneration.

Growth patterns of caudal fin rays are informed by both external signals from the regenerating organ and remembered identity autonomous to the local tissue

Regenerating tissues must remember or interpret their spatial position, using this information to restore original size and patterning. The external skeleton of the zebrafish caudal fin is composed of 18 rays; after any portion of the fin is amputated, position-dependent regenerative growth restores each ray to its original length. We tested for transcriptional differences during regeneration of proximal versus distal tissues and identified 489 genes that differed in proximodistal expression. Thyroid hormone directs multiple aspects of ray patterning along the proximodistal axis, and we identified 364 transcripts showing a proximodistal expression pattern that was dependent on thyroid hormone context. To test what aspects of ray positional identity are directed by extrinsic cues versus remembered identity autonomous to the tissue itself, we transplanted distal portions of rays to proximal environments and evaluated regeneration within the new location. While neighboring proximal tissue showed robust expression of scpp7, a transcript with thyroid-regulated proximal enrichment, regenerating rays originating from transplanted distal tissue showed reduced (distal-like) expression during outgrowth. These distal-to-proximal transplants regenerated far beyond the length of the graft itself, indicating that cues from the proximal environment promoted additional growth. Nonetheless, these transplants initially regenerated at a much slower rate compared to controls, suggesting memory of distal identity was retained by the transplanted tissue. This early growth retardation caused rays that originated from transplants to become noticeably shorter than their native neighboring rays. While several aspects of fin ray morphology (bifurcation, segment length) were found to be determined by the environment, regeneration speed and ray length are remembered autonomously by tissues, persisting across multiple rounds of amputation and regeneration.

The potential of zebrafish as drug discovery research tool in immune-mediated inflammatory disease

Immune-mediated inflammatory disease (IMID) prevalence is estimated at 3-7% for Westernised populations, with annual incidence reported at almost 1 in 100 people globally. More recently, drug discovery approaches have been evolving towards more targeted therapies with an improved long-term safety profile, while the requirement for individualisation of medicine in complex conditions such as IMIDs, is acknowledged. However, existing preclinical models-such as cellular and in vivo mammalian models-are not ideal for modern drug discovery model requirements, such as real-time in vivo visualisation of drug effects, logistically feasible safety assessment over the course of a lifetime, or dynamic assessment of physiological changes during disease development. Zebrafish share high homology with humans in terms of proteins and disease-causing genes, with high conservation of physiological processes at organ, tissue, cellular and molecular level. These and other unique attributes, such as high fecundity, relative transparency and ease of genetic manipulation, positions zebrafish as the next major role player in IMID drug discovery. This review provides a brief overview of the suitability of this organism as model for human inflammatory disease and summarises the range of approaches used in zebrafish-based drug discovery research. Strengths and limitations of zebrafish as model organism, as well as important considerations in research study design, are discussed. Finally, under-utilised avenues for investigation in the IMID context are highlighted.

Analysis of the prognostic, diagnostic and immunological role of HSP90α in malignant tumors

Heat shock protein 90α (HSP90α) encoded by the HSP90AA1 gene, is the stress inducible isoform of the molecular chaperone HSP90, and was demonstrated as a promising hallmark to diagnose, prognosis in malignant tumors. This study is to evaluate the value of HSP90α in diagnosis, prognosis and immunotherapy of malignant tumors by investigating the expression of HSP90α in plasma of various tumors and analyzing the expression of HSP90α at gene and protein levels via pan-cancer database. We founded that levels of HSP90α in malignant tumors groups were significantly higher than healthy controls in serum. Pan-cancer analysis showed that HSP90AA1 was highly expressed in 27 of 33 tumors, but low in individual cancers (such as renal malignancies). The plasma HSP90α level was positively correlated with the stage of malignant tumor, but there was no significant difference between HSP90AA1 and the stage of most tumors. Cox regression analysis showed that HSP90AA1 expression was significantly correlated with OS in only 6 of the 32 cancers, including LIHC, KIRC, HNSC, LUAD, BRCA and MESO. Up-regulation of HSP90AA1 in most tumors was positively correlated with PDCD1LG2 and CD274 immune checkpoint genes. T cell CD8+ was positively correlated with HSP90AA1 in COAD, DLBC and UVM, and negatively correlated with HSP90AA1 in ESCA, GBM, HNSC, KIRC, KIRP, UCEC and STAD. The AUC of HSP90α are generally high in different tumor groups, which indicated its diagnostic value in malignant tumors. In conclusion, serum HSP90α in patients with malignant tumor is generally elevated, which is of positive significance as an independent diagnosis and combined diagnosis. However, we found that the expression level of HSP90AA1 gene in most tumors was not completely consistent with the serum level, and even down-regulated in some tumors. Plasma levels can be used as biomarkers of poor prognosis in some tumors, but it cannot be used as a biomarker for poor prognosis of all tumors, and more in-depth studies are needed.

Effects of Zinc Ions Released From Ti-NW-Zn Surface on Osteogenesis and Angiogenesis In Vitro and in an In Vivo Zebrafish Model

Zinc-modified titanium materials have been widely applied in oral implants. Among them, our previous studies have also successfully prepared a novel acid-etched microstructured titanium surface modified with zinc-containing nanowires (Ti-NW-Zn) and proved its excellent biocompatibility. It is well known that the functional regulation between angiogenesis and osteogenesis is of great importance for bone remodeling around implants. However, there are few reports concerning the biological safety of zinc ions released from materials and the appropriate concentration of released zinc ions which was more conducive to angiogenesis and bone regeneration. In this study, we investigated the effects of zinc ions released from Ti-NW-Zn surfaces on angiogenesis and osteogenesis using the zebrafish model and revealed the relationship between angiogenesis and osteogenesis via HUVECs and MC3T3-E1s in vitro. We found that the zinc ions released from Ti-NW-Zn surfaces, with a concentration lower than median lethal concentrations (LCs) of zebrafish, were biologically safe and promote osteogenesis and angiogenesis in vivo. Moreover, the proper concentration of zinc ions could induce the proliferation of HUVECs and osteogenic differentiation. The positive effects of the appropriate concentration of zinc ions on osteoblast behaviors might be regulated by activating the MAPK/ERK signaling pathway. These aspects may provide new sights into the mechanisms underlying zinc-modified titanium surfaces between osteogenesis and angiogenesis, to lay the foundation for further improving the materials, meanwhile, promoting the applications in dentistry.

Hippo-Yap/Taz signalling in zebrafish regeneration

The extent of tissue regeneration varies widely between species. Mammals have a limited regenerative capacity whilst lower vertebrates such as the zebrafish (Danio rerio), a freshwater teleost, can robustly regenerate a range of tissues, including the spinal cord, heart, and fin. The molecular and cellular basis of this altered response is one of intense investigation. In this review, we summarise the current understanding of the association between zebrafish regeneration and Hippo pathway function, a phosphorylation cascade that regulates cell proliferation, mechanotransduction, stem cell fate, and tumorigenesis, amongst others. We also compare this function to Hippo pathway activity in the regenerative response of other species. We find that the Hippo pathway effectors Yap/Taz facilitate zebrafish regeneration and that this appears to be latent in mammals, suggesting that therapeutically promoting precise and temporal YAP/TAZ signalling in humans may enhance regeneration and hence reduce morbidity.