The dynamic genome of Hydra.

The freshwater cnidarian Hydra was first described in 1702 and has been the object of study for 300 years. Experimental studies of Hydra between 1736 and 1744 culminated in the discovery of asexual reproduction of an animal by budding, the first description of regeneration in an animal, and successful transplantation of tissue between animals. Today, Hydra is an important model for studies of axial patterning, stem cell biology and regeneration. Here we report the genome of Hydra magnipapillata and compare it to the genomes of the anthozoan Nematostella vectensis and other animals. The Hydra genome has been shaped by bursts of transposable element expansion, horizontal gene transfer, trans-splicing, and simplification of gene structure and gene content that parallel simplification of the Hydra life cycle. We also report the sequence of the genome of a novel bacterium stably associated with H. magnipapillata. Comparisons of the Hydra genome to the genomes of other animals shed light on the evolution of epithelia, contractile tissues, developmentally regulated transcription factors, the Spemann-Mangold organizer, pluripotency genes and the neuromuscular junction.

Real-time assessment of encapsulated neonatal porcine islets prior to clinical xenotransplantation.

BACKGROUND: Porcine islet transplantation is emerging as an attractive option for the treatment of patients with type 1 diabetes, with the possibility of providing islets of higher and more consistent quality and in larger volumes than available from human pancreata. The use of encapsulated neonatal porcine islets (ENPI) is appealing because it can address islet supply limitations while reducing the need for anti-rejection therapy. Pre-transplant characterization of ENPI viability and potency is an essential component of the production process. We applied the validated assay for oxygen consumption rate normalized for DNA content (OCR/DNA) to characterize ENPI viability. METHODS: ENPI of low viscosity and high m alginate were prepared according to standard methods and characterized at various culture time points up to 5 weeks. RESULTS: The OCR/DNA (nmol/min·mgDNA ± SEM) of ENPI (235 ± 10, n = 9) was comparable to that of free NPI (255 ± 14, n = 13). After encapsulation, NPI OCR/DNA was sustained over a culture period of up to 5 weeks. The average OCR/DNA of ENPI cultured longer than 9 days was higher than that of freshly encapsulated NPI. CONCLUSION: This is the first characterization of ENPI by a validated and more sensitive method for product viability. The NPI encapsulation process does not compromise viability as measured by OCR/DNA, and ENPI can be cultured for up to 5 weeks with maintenance of viability. ENPI meet or exceed current adult porcine islet product release criteria (established at the University of Minnesota) for preclinical xenotransplantation in terms of OCR/DNA.

beta-catenin plays a central role in setting up the head organizer in hydra.

In an adult hydra the head organizer, located in the hypostome, is constantly active in maintaining the structure of the animal in the context of its steady state tissue dynamics. Several Wnt genes, TCF, and elevated levels of beta-catenin are expressed in the hypostome as well as during the formation of a new organizer region in developing buds suggesting they play a role in the organizer. Transgenic hydra were generated in which a modified hydra beta-catenin gene driven by an actin promoter is continuously expressed at a high level throughout the animal. These animals formed heads and secondary axes in multiple locations along the body column. Transplantation experiments indicate they have a high and stable level of head organizer activity throughout the body columns. However, none of the Wnt genes are expressed in the body columns of these transgenic animals. Further, in alsterpaullone-treated animals, which results in a transient rise in head organizer activity throughout the body column, the time of expression of the Wnt genes is much shorter than the time of the elevated level of head inducing activity. These results for the first time provide direct functional evidence that beta-catenin plays a crucial role in the maintenance and activity of the head organizer and suggest that Wnt ligands may be required only for the initiation but not in maintenance of the organizer in Hydra.

Chemosensitivity assessments of curdlan-doped smart nanocomposites containing erlotinib HCl.

Curdlan (CN)-doped montmorillonite/poly(N-isopropylacrylamide-co-N,N'-methylene-bis-acrylamide) [CN/MT/P(NIPA-co-MBA)] smart nanocomposites (NCs) were developed for efficient erlotinib HCl (ERL) delivery to lung cancer cells. The placebo NCs demonstrated excellent biodegradability, pH/thermo-responsive swelling profiles and declined molar mass (M¯c) between the crosslinks with increasing temperature. The XRD, FTIR, DSC, TGA, and SEM analyses revealed the architectural chemistry of these NC scaffolds. The NCs loaded with ERL (F-1-F-3) displayed acceptable diameter (734-1120 nm) and zeta potential (+1.16 to -11.17 mV), outstanding drug entrapping capability (DEE, 78-99%) and sustained biphasic ERL elution patterns (Q8h, 53-91%). The ERL release kinetics of the optimal matrices (F-3) obeyed Higuchi model and their transport occurred through anomalous diffusion. The mucin adsorption behaviour of these matrices followed Freudlich isotherms. As compared to pure ERL, the formulation (F-3) displayed an improved anti-proliferative potential and induced apoptosis more effectively on A549 cells. Thus, the CN-doped smart NCs could be utilized as promising drug-cargoes for lung cancer therapy.

Uncoupling Molecular Testing for SARS-CoV-2 From International Supply Chains.

The rapid global rise of COVID-19 from late 2019 caught major manufacturers of RT-qPCR reagents by surprise and threw into sharp focus the heavy reliance of molecular diagnostic providers on a handful of reagent suppliers. In addition, lockdown and transport bans, necessarily imposed to contain disease spread, put pressure on global supply lines with freight volumes severely restricted. These issues were acutely felt in New Zealand, an island nation located at the end of most supply lines. This led New Zealand scientists to pose the hypothetical question: in a doomsday scenario where access to COVID-19 RT-qPCR reagents became unavailable, would New Zealand possess the expertise and infrastructure to make its own reagents onshore? In this work we describe a review of New Zealand's COVID-19 test requirements, bring together local experts and resources to make all reagents for the RT-qPCR process, and create a COVID-19 diagnostic assay referred to as HomeBrew (HB) RT-qPCR from onshore synthesized components. This one-step RT-qPCR assay was evaluated using clinical samples and shown to be comparable to a commercial COVID-19 assay. Through this work we show New Zealand has both the expertise and, with sufficient lead time and forward planning, infrastructure capacity to meet reagent supply challenges if they were ever to emerge.

Multiple Wnts are involved in Hydra organizer formation and regeneration.

Wnt genes and beta-catenin signaling are involved in axial patterning processes in vertebrate embryogenesis in setting up the Spemann-Mangold organizer in amphibian embryos. An organizer with a similar function is present in the hypostome of an adult Hydra polyp. Previously, a Hydra ortholog of Wnt3 (HyWnt3), which is expressed in the hypostome, has been described. Here, ten additional Hydra Wnt genes have been identified. Of these, six (HyWnt1, -7, -9/10a, -9/10c, -11, and -16) are expressed in the adult hypostome. And, as is HyWnt3, these six Wnt genes are also expressed when a new head organizer is formed during head regeneration and bud formation. The kinetics of Wnt gene expressions during head regeneration suggests that a cascade of consecutive Wnt activation accompanies regeneration, and HyWnt3 begins this cascade. Recombinant HyWnt3 protein induced body column tissue to undergo head formation. It also increased the head formation capacity in the head regeneration-deficient mutant strain reg-16 to that of wild-type strains. In addition our data reveal striking similarities in the molecular basis of the organizer in Hydra and axis polarization in chordates (e.g. Spemann's organizer) as well as it's role in regeneration suggesting a conserved function of Wnt signaling in setting up this ancient metazoan signaling center.

Targeting connexin43 expression accelerates the rate of wound repair.

The repair of tissue damage is a key survival process in all organisms and involves the coordinated activation of several cell types. Cell-cell communication is clearly fundamental to this process, and a great deal is known about extracellular communication within the wound site via cytokines. Here we show that direct cell-cell communication through connexin 43 (Cx43) gap junction channels also plays a major role in the wound healing process. In two different wound healing models, incisional and excisional skin lesions, we show that a single topical application of Cx43 antisense gel brings about a transient downregulation of Cx43 protein levels, and this results in a dramatic increase in the rate of wound closure. Cx43 knockdown reduces inflammation, seen both macroscopically, as a reduction in swelling, redness, and wound gape, and microscopically, as a significant decrease in neutrophil numbers in the tissue around the wound. One long-term consequence of the improved rate of healing is a significant reduction in the extent of granulation tissue deposition and the subsequent formation of a smaller, less distorted, scar. This approach is likely to have widespread therapeutic applications in other injured tissues and opens up new avenues of research into improving the wound healing process.

In vitro optimization of antisense oligodeoxynucleotide design: an example using the connexin gene family.

The completion of the human and mouse genomes has identified at least 20 connexin isomers in this family of intercellular channel proteins. However, there are no specific gap junction blockers or channel-blocking mimetic peptides available for the study of specific connexins. We designed antisense oligodeoxynucleotides that functionally reduce targeted connexin protein expression and can be used to reveal the biological function of individual connexins in vivo. Connexin mRNA was firstly exposed in vitro to deoxyribozymes complementing the sense coding sequence. Those that cleaved the target connexin mRNA in defined regions were used as the basis to design oligodeoxynucleotides to the accessible sites, thus taking into account tertiary mRNA configurations rather than relying on computed predictions. Antisense oligodeoxynucleotides designed to bind to accessible mRNA sites selectively reduced connexin26 and -43 mRNA expression in a corneal epithelium ex vivo model. Connexin43 protein levels were reduced correlating with the knockdown in mRNA and the protein's rapid turnover; protein levels of connexin26 did not alter, supporting lower turnover rates reported for that protein. We show, for the first time, an inexpensive and empirical approach to the preparation of specific and functional antisense oligodeoxynucleotides against known gene targets in the post-genomic era.

Improving alginate-poly-L-ornithine-alginate capsule biocompatibility through genipin crosslinking.

DIABECELL® capsules comprise an inner core of alginate (Alg) coated with a polycationic polymer, poly-L-ornithine (PLO), designed as a stabilizing agent for strengthening the capsule wall, which is masked by an outer layer of biocompatible Alg. These polymeric microcapsules have demonstrated excellent mechanical properties and a reduction in hypoglycemia after tranplantation in human clinical trials; however, degradation of the outer Alg layer leaves the underlying layers of PLO exposed, which ultimately leads to reduced biocompatibility in vivo. Here we aim to improve capsule biocompatibility and to increase the hydrophilic properties of the capsule surface through chemical crosslinking/modification of the PLO layer using genipin. Fluorescence microscopy established crosslinking was limited to the layers of PLO. In vitro experiments confirmed islet viability and insulin release within chemically modified capsules over the course of a month and in vivo investigations demonstrated improved biocompatibility when comparing standard Alg/PLO/Alg capsules with genipin modified capsules.

Recovery of neurological functions in non-human primate model of Parkinson's disease by transplantation of encapsulated neonatal porcine choroid plexus cells.

Parkinson's disease (PD) is a neurodegenerative disease that is primarily characterized by degeneration of dopaminergic (DA) neurons in the substantia nigra (SN) and a loss of their fibre projections in the striatum. We utilized the neonatal porcine choroid plexus (CP), an organ that secretes cerebrospinal fluid containing various types of neurotrophic and neuroprotective factors, to ameliorate the Parkinsonian symptoms in MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-treated rhesus monkeys without requiring immunosuppression. We demonstrate that transplanted encapsulated CP clusters (eCPs) significantly improved neurological functions in MPTP-treated monkeys during the course of six months after transplantation (p < 0.001) when compared with monkeys implanted with empty capsules or subjected to sham surgery. The improvement in neurological scores was accompanied by a corresponding improvement in apomorphine-induced circling behaviour (p < 0.001) as well as increased tyrosine hydroxylase (TH) staining in the striatum. Our results suggest that eCPs are a promising cell therapeutic agent to treat Parkinson's disease.

Knockdown of connexin43-mediated regulation of the zone of polarizing activity in the developing chick limb leads to digit truncation.

In the developing chick wing, the use of antisense oligodeoxynucleotides to transiently knock down the expression of the gap junction protein, connexin43 (Cx43), results in limb patterning defects, including deletion of the anterior digits. To understand more about how such defects arise, the effects of transient Cx43 knockdown on the expression patterns of several genes known to play pivotal roles in limb formation were examined. Sonic hedgehog (Shh), which is normally expressed in the zone of polarizing activity (ZPA) and is required to maintain both the ZPA and the apical ectodermal ridge (AER), was found to be downregulated in treated limbs within 30 h. Bone morphogenetic protein-2 (Bmp-2), a gene downstream of Shh, was similarly downregulated. Fibroblast growth factor-8 expression, however, was unaltered 30 h after treatment but was greatly reduced at 48 h post-treatment, when the AER begins to regress. Expressions of Bmp-4 and Muscle segment homeobox-like gene (Msx-1) were not affected at any of the time points examined. Cx43 expression is therefore involved in some, but not all patterning cascades, and appears to play a role in the regulation of ZPA activity.