Rare diseases (RDs) affect approximately 8% of all people or > 400 million people globally. The Australian Government's National Strategic Action Plan for Rare Diseases has identified the need for a ...national, coordinated, and systematic approach to the collection and use of RD data, including registries. Rare disease registries (RDRs) are established for epidemiological, quality improvement and research purposes, and they are critical infrastructure for clinical trials. The aim of this scoping review was to review literature on the current state of RDRs in Australia; to describe how they are funded; what data they collect; and their impact on patient outcomes.
We conducted a literature search on MEDLINE, EMBASE, CINAHL and PsychINFO databases, in addition to Google Scholar and grey literature. Dissertations, government reports, randomised control trials, conference proceedings, conference posters and meeting abstracts were also included. Articles were excluded if they did not discuss RDs or if they were written in a language other than English. Studies were assessed on demographic and clinical patient characteristics, procedure or treatment type and health-related quality of life captured by RDRs or databases that have been established to date.
Seventy-four RDRs were identified; 19 were global registries in which Australians participated, 24 were Australian-only registries, 10 were Australia and New Zealand based, and five were Australian jurisdiction-based registries. Sixteen "umbrella" registries collected data on several different conditions, which included some RDs, and thirteen RDRs stored rare cancer-specific information. Most RDRs and databases captured similar types of information related to patient characteristics, comorbidities and other clinical features, procedure or treatment type and health-related quality of life measures. We found considerable heterogeneity among existing RDRs in Australia, especially with regards to data collection, scope and quality of registries, suggesting a national coordinated approach to RDRs is required.
This scoping review highlights the current state of Australian RDRs, identifying several important gaps and opportunities for improvement through national coordination and increased investment.
Abstract
Background
Rare disease registries (RDRs) facilitate monitoring of rare diseases by pooling small datasets to increase clinical and epidemiological knowledge of rare diseases and promote ...patient centred best practice. The aim of this study was to understand the current state of RDRs in Australia, data captured, impact on patient outcomes, funding models, and barriers and enablers regarding their establishment and maintenance.
Methods
An exploratory sequential mixed methods study design was adopted. First, a list of Australian RDRs, primary contacts and data custodians was generated through online and consumer group (Rare Voices Australia (RVA)) contacts. A cross-sectional, anonymous online survey was distributed to registry custodians, managers, or principal investigators of 74 identified Australian RDRs, 88 RVA Partners, 17 pharmaceutical organizations and 12 RVA Scientific and Medical Advisory Committee members. Next, managers and coordinators of RDRs and databases who participated in the survey were invited to participate in semi-structured interviews. Quantitative and qualitative data were analysed using basic descriptive statistics and content analysis, respectively.
Results
Forty RDRs responded to the survey; nine were national, five were based in Australia and New Zealand, and the remaining were global. Of the 40 survey respondents, eight were interviewed. Most of the RDRs captured similar information regarding patient characteristics, comorbidities and clinical features, diagnosis, family history, genetic testing, procedures or treatment types, response to treatments and complications of treatments. Better treatment outcomes, changes in process of care and changes in quality of care were the most frequently reported benefits of the RDRs. The main challenges proved to be cost/funding of data collection, data completeness, and patient consent. When asked, the participants identified opportunities and challenges regarding potential options to streamline RDRs in Australia in the future.
Conclusion
Findings from this study highlighted significant dataset heterogeneity based on the individual disease, and current lack of interoperability and coordination between different existing RDRs in Australia. Nevertheless, a nationally coordinated approach to RDRs should be investigated given the particular benefits RDRs offer, such as access to research and the monitoring of new disease-modifying treatments.
Hematopoietic stem cells (HSCs) with superior reconstitution potential are reported to be enriched in the endosteal compared to central bone marrow (BM) region. To investigate whether specific ...factors at the endosteum may contribute to HSC potency, we screened for candidate HSC niche factors enriched in the endosteal compared to central BM regions. Together with key known HSC supporting factors Kitl and Cxcl12, we report that prostacyclin/prostaglandin I2 (PGI2) synthase (Ptgis) was one of the most highly enriched mRNAs (>10‐fold) in endosteal compared to central BM. As PGI2 signals through receptors distinct from prostaglandin E2 (PGE2), we investigated functional roles for PGI2 at the endosteal niche using therapeutic PGI2 analogs, iloprost, and cicaprost. We found PGI2 analogs strongly reduced HSC differentiation in vitro. Ex vivo iloprost pulse treatment also significantly boosted long‐term competitive repopulation (LT‐CR) potential of HSCs upon transplantation. This was associated with increased tyrosine‐phosphorylation of transducer and activator of transcription‐3 (STAT3) signaling in HSCs but not altered cell cycling. In vivo, iloprost administration protected BM HSC potential from radiation or granulocyte colony‐stimulating factor‐induced exhaustion, and restored HSC homing potential with increased Kitl and Cxcl12 transcription in the BM. In conclusion, we propose that PGI2 is a novel HSC regulator enriched in the endosteum that promotes HSC regenerative potential following stress.
Prostacyclin/prostaglandin I2 (PGI2) is a novel hematopoietic stem cell (HSC) regulatory factor enriched at the endosteum. PGI2 is synthesized by prostacyclin syntase (PTGIS) expressed mainly by osteoblasts, mesenchymal stromal cells and endothelial cells. Ex vivo and in vivo treatment with PGI2 analogs enhance HSC long‐term competitive repopulation potential and protect reconstituting HSC from stress.
Cadherin-based cell-cell contacts are prominent sites for phosphotyrosine signaling, being enriched in tyrosine-phosphorylated proteins and tyrosine kinases and phosphatases. The functional interplay ...between cadherin adhesion and tyrosine kinase signaling, however, is complex and incompletely understood. In this report we tested the hypothesis that cadherin adhesion activates c-Src signaling and sought to assess its impact on cadherin function. We identified c-Src as part of a cadherin-activated cell signaling pathway that is stimulated by ligation of the adhesion receptor. However, c-Src has a biphasic impact on cadherin function, exerting a positive supportive role at lower signal strengths, but inhibiting function at high signal strengths. Inhibiting c-Src under circumstances when it is activated by cadherin adhesion decreased several measures of cadherin function. This suggests that the cadherin-activated c-Src signaling pathway serves positively to support cadherin function. Finally, our data implicate PI3-kinase signaling as a target for cadherin-activated c-Src signaling that contributes to its positive impact on cadherin function. We conclude that E-cadherin signaling is an important activator of c-Src at cell-cell contacts, providing a key input into a signaling pathway where quantitative changes in signal strength may result in qualitative differences in functional outcome.
Classical cadherin adhesion molecules are key determinants of cell-cell recognition during development and in post-embryonic life. A decisive step in productive cadherin-based recognition is the ...conversion of nascent adhesions into stable zones of contact. It is increasingly clear that such contact zone extension entails active cooperation between cadherin adhesion and the force-generating capacity of the actin cytoskeleton. Cortactin has recently emerged as an important regulator of actin dynamics in several forms of cell motility. We now report that cortactin is recruited to cell-cell adhesive contacts in response to homophilic cadherin ligation. Notably, cortactin accumulates preferentially, with Arp2/3, at cell margins where adhesive contacts are being extended. Recruitment of cortactin is accompanied by a ligation-dependent biochemical interaction between cortactin and the cadherin adhesive complex. Inhibition of cortactin activity in cells blocked Arp2/3-dependent actin assembly at cadherin adhesive contacts, significantly reduced cadherin adhesive contact zone extension, and perturbed both cell morphology and junctional accumulation of cadherins in polarized epithelia. Together, our findings identify a necessary role for cortactin in the cadherin-actin cooperation that supports productive contact formation.
Classical cadherin adhesion molecules are fundamental determinants of cell-cell recognition that function in cooperation with the actin cytoskeleton. Productive cadherin-based cell recognition is ...characterized by a distinct morphological process of contact zone extension, where limited initial points of adhesion are progressively expanded into broad zones of contact. We recently demonstrated that E-cadherin ligation recruits the Arp2/3 actin nucleator complex to the plasma membrane in regions where cell contacts are undergoing protrusion and extension. This suggested that Arp2/3 might generate the protrusive forces necessary for cell surfaces to extend upon one another during contact assembly. We tested this hypothesis in mammalian cells by exogenously expressing the CA region of N-WASP. This fragment, which potently inhibits Arp2/3-mediated actin assembly in vitro, also effectively reduced actin assembly at cadherin adhesive contacts. Blocking Arp2/3 activity by this strategy profoundly reduced the ability of cells to extend cadherin adhesive contacts but did not affect cell adhesiveness. These findings demonstrate that Arp2/3 activity is necessary for cells to efficiently extend and assemble cadherin-based adhesive contacts.
Src family kinases (SFKs) signal in response to E-cadherin to support cadherin adhesion and the integrity of cell-cell contacts (McLachlan, R. W., Kraemer, A., Helwani, F. M., Kovacs, E. M., and Yap, ...A. S. (2007) Mol. Biol. Cell 18, 3214–3223). We now identify the actin-regulatory protein, cortactin, as a target of E-cadherin-activated SFK signaling. Tyr-phosphorylated cortactin was found at cell-cell contacts in established epithelial monolayers, and cortactin became acutely tyrosine-phosphorylated when E-cadherin adhesion was engaged. In all circumstances, cortactin tyrosine phosphorylation was blocked by inhibiting SFK signaling. Importantly, Tyr-phosphorylated cortactin was necessary to preserve the integrity of cadherin contacts and the perijunctional actin cytoskeleton. Moreover, expression of a phosphomimetic cortactin mutant could prevent SFK blockade from disrupting cadherin organization, thereby placing cortactin functionally downstream of SFK signaling at cadherin adhesions. We conclude that SFK and cortactin constitute an important signaling pathway that functionally links E-cadherin adhesion and the actin cytoskeleton.
Osteoblasts are necessary to B lymphopoiesis and mobilizing doses of G-CSF or cyclophosphamide inhibit osteoblasts, whereas AMD3100/Plerixafor does not. However, the effect of these mobilizing agents ...on B lymphopoiesis has not been reported. Mice (wild-type, knocked-out for TNF-α and TRAIL, or over-expressing Bcl-2) were mobilized with G-CSF, cyclophosphamide, or AMD3100. Bone marrow, blood, spleen and lymph node content in B cells was measured. G-CSF stopped medullar B lymphopoiesis with concomitant loss of B-cell colony-forming units, pre-pro-B, pro-B, pre-B and mature B cells and increased B-cell apoptosis by an indirect mechanism. Overexpression of the anti-apoptotic protein Bcl2 in transgenic mice rescued B-cell colony forming units and pre-pro-B cells in the marrow, and prevented loss of all B cells in marrow, blood and spleen. Blockade of endogenous soluble TNF-α with Etanercept, or combined deletion of the TNF-α and TRAIL genes did not prevent B lymphopoiesis arrest in response to G-CSF. Unlike G-CSF, treatments with cyclophosphamide or AMD3100 did not suppress B lymphopoiesis but caused instead robust B-cell mobilization. G-CSF, cyclophosphamide and AMD3100 have distinct effects on B lymphopoiesis and B-cell mobilization with: 1) G-CSF inhibiting medullar B lymphopoiesis without mobilizing B cells in a mechanism distinct from the TNF-α-mediated loss of B lymphopoiesis observed during inflammation or viral infections; 2) CYP mobilizing B cells but blocking their maturation; and 3) AMD3100 mobilizing B cells without affecting B lymphopoiesis. These results suggest that blood mobilized with these three agents may have distinct immune properties.
In the bone marrow, hematopoietic stem cells (HSCs) reside in specific niches near osteoblast-lineage cells at the endosteum. To investigate the regulation of these endosteal niches, we studied the ...mobilization of HSCs into the bloodstream in response to granulocyte colony-stimulating factor (G-CSF). We report that G-CSF mobilization rapidly depletes endosteal osteoblasts, leading to suppressed endosteal bone formation and decreased expression of factors required for HSC retention and self-renewal. Importantly, G-CSF administration also depleted a population of trophic endosteal macrophages (osteomacs) that support osteoblast function. Osteomac loss, osteoblast suppression, and HSC mobilization occurred concomitantly, suggesting that osteomac loss could disrupt endosteal niches. Indeed, in vivo depletion of macrophages, in either macrophage Fas-induced apoptosis (Mafia) transgenic mice or by administration of clodronate-loaded liposomes to wild-type mice, recapitulated the: (1) loss of endosteal osteoblasts and (2) marked reduction of HSC-trophic cytokines at the endosteum, with (3) HSC mobilization into the blood, as observed during G-CSF administration. Together, these results establish that bone marrow macrophages are pivotal to maintain the endosteal HSC niche and that the loss of such macrophages leads to the egress of HSCs into the blood.
Haematopoietic stem cells (HSCs) are regulated by their immediate microenvironment or niche. The most potent functional HSCs are enriched at the endosteum near the bone, which comprises ~10% of total ...bone marrow (BM). To identify novel niche factors that regulate HSCs, we performed a gene expression microarray seeking genes that were >2-fold overexpressed in the endosteal BM relative to the central BM. In this screen, we uncovered known essential HSC niche factors overexpressed in the endosteal BM such as Scf, Cxcl12, and Angpt1, which validated our approach.
Among the genes overexpressed in the endosteal BM, prostaglandin I2 (PGI2) synthase (Ptgis) was one of the highest enriched genes in the endosteum (>10-fold by qRT-PCR, p<0.001). Within the endosteal BM, Ptgis was most abundantly expressed by osteoblasts, followed by mesenchymal stem/progenitor cells and endothelial cells. Ptgis is the sole enzyme responsible for biosynthesis of PGI2, originally discovered as a potent anti-thrombotic and vasodilating agent. PGI2 has no reported roles in HSC regulation in the BM and was chosen as candidate niche factor for further investigation. Due to the extreme lability of PGI2, we employed a clinically approved PGI2 analogue iloprost for all subsequent experiments.
In initial experiments where we cultured fluorescence activated cell sorted (FACS) BM lineage- Kit+ Sca-1- (LKS+) haematopoietic stem and progenitor cells (HSPCs) for 7 days in serum free conditions, we found iloprost treatment potently reduced proliferation and differentiation compared to vehicle controls, assessed by flow cytometry phenotyping (p<0.0001). To determine whether iloprost treatment alters HSC function, we pulse treated whole BM cells with iloprost for 1 hour before competitive transplant and found iloprost pulse-treatment resulted in 14-fold increased multilineage reconstitution potential (p<0.05). This suggests that PGI2 enhances HSC function by dampening differentiation.
We next sought to determine whether iloprost affects HSC function in vivo. In steady state, low dose 0.1mg/kg iloprost administration to mice for 15 days did not alter BM HSPC phenotypes by flow cytometry nor HSC reconstitution potential in competitive transplants compared to vehicle controls suggesting PGI2 does not alter HSC function in homeostasis. To further test the effect of PGI2 following stress, mice were sub-lethally (6.5 Gy) irradiated or administered pro-inflammatory granulocyte colony stimulating factor (G-CSF) for 3 days. We found low dose iloprost administration partially rescued BM HSC reconstitution potential 21 days following irradiation (p<0.05) or 3 days following G-CSF administration (p<0.01). These data suggest that PGI2 protects HSC from stress.
To understand the extrinsic mechanisms through which PGI2 regulates HSC in the BM following stress, we performed a HSC homing assay using naïve donors transplanted into 2-day G-CSF administered recipients. Analysis of HSPC homing to the BM at 4 hours post-transplantation revealed ~4-fold greater proportion of LKS+ HSPC homing to the BM of iloprost co-administered recipients compared to vehicle controls (p<0.01). We assessed mRNA expression of essential HSC niche factors in the BM of 2-day G-CSF-administered mice and found that G-CSF administration decreased Scf and Cxcl12 expression, which were both partially rescued with iloprost co-administration (p<0.05). Together the data suggest that preservation of the BM niche function is one of the mechanisms through which PGI2 protects HSC during stress.
In summary, we have identified PGI2 as a novel HSC niche factor abundant in the endosteal BM. PGI2 analogues like Iloprost are well-tolerated and used clinically to treat vascular diseases such as pulmonary arterial hypertension and Raynaud's phenomenon. Our research suggests that PGI2 analogues can be rapidly repurposed in the clinic to improve HSC transplant outcomes and protect against BM failure following acute stressors such as accidental irradiation or inflammation.
Levesque:GlycoMimetics: Equity Ownership, Patents & Royalties.
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