Difference between revisions of "Talk:2016 Group 1 Project"
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Please put your peer reviews here
Please put your peer reviews here
Revision as of 10:51, 10 May 2016
|Group Projects - Blood Cell Biology - Updated 21 April|
|This year's main topic is Blood Cell Biology. Each group should discuss with group members the specific sub-topic that will be covered by their project.
Here is a list of some of the cell types (Structure and Function)
Embryology - content cannot be reused but a useful resource about cell development.
Histology - images these can be reused in your projects.
|Group Assessment Criteria|
Group Assessment Criteria
Z5020175 (talk) 21:05, 22 March 2016 (AEDT) Hi Guys, my name is Matthew and I was wondering which blood cell type you would like to choose as a research topic? From the list, I actually find mast cells and megakaryocytes to be quite interesting, but we will work out which one is best for all of us. Also, it would be appreciated if you could write out your names so that we know who is in the group! Thankyou.
-how are they generated
- life expectancy
- why only located in bone marrow - function
- whats special about cell division
- direction of research (currently )
- sub heading on Platelets (as they come from Megakaryocytes)
- internal structure and common structure
- manufacture (made in bone marrow?)
- special features (surface receptors etc)
- history and who discovered them
- images, videos
- we are all about clarity!
Paper 1: Ciovacco et al.  examined the complex interplay between megakaryocytes and bone development. They had done so through studying the effect of megakaryocyte (MK) maturation and numbers on osteoblast proliferation and osteoclast inhibition. Megakaryocytes from the wild type C57BL/6 mice were assorted into 3 sub - populations based on their increasing levels of maturity: megakaryoblasts, immature MK and mature MK. These cells were incubated with the same numbers of osteoblasts in separate cultures respectively. In conjunction, two other cultures were also made: osteoblasts alone and osteoblasts with BSA separated MKs. These were the negative and positive controls respectively. The same experiment was repeated with the use of osteoclasts instead. The numbers of bone cells within each experiment were recorded after 3 days of incubation and it was determined that megakaryoblasts do not exhibit a proliferative or inhibitory effect on osteoblasts and osteoclasts respectively. However, this was not the case for immature and mature MKs, as they were able to enhance the proliferation of osteoblasts and inhibit the formation of osteoclasts at virtually identical levels. This study was also able to demonstrate that as the numbers of megakaryocytes increase, so does the level of osteoblast proliferation. Overall, it was illustrated that the effect of megakaryocytes on bone growth is complex and determined by multiple factors such as their level of maturity and population numbers. This article is therefore relevant to the 'function and roles' subsection as one of the main functions of megakaryocytes is the regulation of skeletal homeostasis.
Paper 2: Uchiyama et al.  studies the role of growth differentiation factor 15 (GDF15) in the pathogenesis of primary myelofibrosis (PMF) which is a severe disorder that involves bone marrow fibrosis. The serum of patients with PMF were analysed within this study and nearly all patients demonstrated abnormally high levels of GDF15. This led the researchers to determine the source of this cytokine and it was found to be megakaryocytes within the bone marrow. Relative to other cell populations within the bone marrow of patients with PMF, megakaryocytes demonstrated greater haematoxylin and eosin staining and this means that the expression of GDF15 predominantly occurs in megakaryocytes. The numbers of these precursor cells are also known to be elevated in PMF and GDF15 was shown to be upregulated in megakaryocytes of patients with PMF when compared to expression levels in normally healthy individuals. The study had further found that GDF15 was responsible for the abnormal proliferation of fibroblasts and osteoblasts in the bone marrow of PMF patients. These two cells are known to cause the fibrosis of the bone marrow in PMF which leads to an inability to generate cells of the blood. Hence, megakaryocytes appear to play a regulatory role in the biogenesis of fibroblasts and osteoblasts in the bone marrow, through signalling molecules such as GDF15. This undoubtingly highlights the relevance of this article to both our 'disease' and 'function/roles' subsections as it explores the complex interaction between megakaryocytes and the cells that lead to fibrosis in PMF.
Paper 3: Within this study, Nishimura et al.  has identified an alternative pathway that involves megakaryocyte rupture and thereby enhanced platelet release in response to acute platelet needs mediated by Interlukin-1α (IL-1α). The main mode of platelet production is regulated by the molecule 'thrombopoietin' (TPO) which promotes a "microtubule - dependent extension of elongated pseudopodal structures" that eventually break off from the megakaryocyte as platelets. The process of generating these megakaryocyte projections is known as 'proplatelet formation' (PPF). The results of this study illustrate that PPF alone is not sufficient in producing the rapid platelet turnover required to meet acute platelet needs in inflammatory reactions. They demonstrate that there is an additional pathway of platelet production (thrombopoesis) mediated by IL-1α. Using a screening assay, it was determined that IL-1α is able to increase platelet production from megakaryocytes to a greater degree than TPO. By studying the effects of exogenous IL-1α on bone marrow megakaryocytes in vivo, it was found that IL-1α significantly enhanced megakaryocyte rupture but notably reduced PPF without altering the serum levels of TPO. The loss of PPF was due to the impairment of microtubule assembly and weakening of the plasma membrane by the IL-1α signalling pathway. The platelets from this cytokine mediated rupture were larger in size than those produced by PPF but demonstrated the same aggregation and thrombotic functions. This article evidently related to the 'function and roles' subsection as it illustrates the importance of megakaryocytes in platelet production under both physiologically normal and stress conditions.
Paper 4: Zhao et al.  sets out to illustrate the dual role of megakaryocytes (MKs) in maintaining HSC quiescence during homeostasis and promoting the repletion of haematopoietic stem cells (HSCs) following chemotherapeutic stress. Many cell types in the bone marrow stroma have been identified as HSC-regulating niche cells. However, whether a HSC progeny is recruited as a HSC niche cell is not clearly known and is thought to be regulated by megakaryocyte secretions. The results of this study show that MKs have physical interactions with HSCs in mice bone marrow and that a deficiency of MKs will lead quiescent HSCs to become activated and thereby proliferate rapidly. In comparison to other stromal niche cells, MKs were revealed to express higher levels of biologically active transforming growth factor β1 (TGF-β1 ) through analysing RNA sequencing data. When MKs are removed from the bone marrow, the levels of functional TGF-β1 protein and nuclear-localized phosphorylated SMAD2/3 (pSMAD2/3) is significantly lowered in the resident HSCs. This insinuates that the HSCs are kept in the quiescent state through the TGF-β-SMAD signalling pathway triggered by megakaryocyte secretions. In order to prove this further, the researchers had injected TGF-β1 into mice with MK ablation and this had reverted the actively proliferating HSCs into a quiescent state. When this injection was depleted, the quiescent HSCs became activated and there was an increase in their proliferative activity. Thus, it is apparent that TGF-β1 which is primarily expressed by MKs, is the key signal in maintaining HSC quiescence. Moreover, there was a significant impairment in the expansion of HSCs when the test mice were under chemotherapy. During this stress phase, megakaryocytes were observed to release fibroblast growth factor 1 (FGF1) which had appeared to override the inhibitory signal induced by TGF-β1. This had temporarily enabled the quiescent HSCs to become activated and clonally expand. On the whole, the data produced in this article is relevant to the 'function and roles' subsection as it highlights the importance of megakaryocytes in maintaining HSC homeostasis through the secretion of signalling molecules.
Lab 3 Assessment
1. Xie, X. (2002). Thrombopoietin promotes mixed lineage and megakaryocytic colony-forming cell growth but inhibits primitive and definitive erythropoiesis in cells isolated from early murine yolk sacs. Blood, 101(4), pp.1329-1335.
This article tested the effects of thrombopoietin to early embryonic cells (E6.5-7.5) which includes hematopoietic stem cells and erythroid cells in an assay. While thrombopoietin alone failed to give any effect, when added alongside growth factors, erythroid growth was inhibited and megakaryopoiesis was enhanced. This showed that thrombopoietin and growth / transcription factors have significant role in regulating differentiation of hematopoietic stem cells to different types of circulatory cells. 
2. Ono-Uruga, Y., Tozawa, K., Horiuchi, T., Murata, M., Okamoto, S., Ikeda, Y., Suda, T. and Matsubara, Y. (2016). Human adipose tissue-derived stromal cells can differentiate into megakaryocytes and platelets by secreting endogenous thrombopoietin. J Thromb Haemost
Ono-Uruga et al. discovered that adipose tissue-derived stromal cells (ASC) can differentiate into megakaryocytes under the effects of endogenous thrombopoietin. It is also found that CD71, a transferrin receptor is a main contributor for thrombopoietin endogenous release in MK progenitor cells among human ASCs. In the experiment, CD71-positive ASC cells induced a higher levels of thrombopoietin endogenesis compared to CD71-negative cells. Therefore, higher levels of CD71-positive cells act as a significant sign to the process of megakaryopoiesis in humans. 
3. Carow, C., Fox, N. and Kaushansky, K. (2001). Kinetics of endomitosis in primary murine megakaryocytes. J. Cell. Physiol., 188(3), pp.291-303.
Megakaryocytes are differentiated from diploid megakaryocyte progenitor cells via endomitosis (EnM), continuous synthesis of genetic materials (ie. DNA) without undergoing cellular division (mitosis). S-phase length in EnM Megakaryocytes is the same as in other blood-cell cycles, with G1 and G2 slightly shortened. However the M-Phase (mitotic phase), is significantly shortened or even nonexistent in some observed cells. The research showed decomposing of spindle fibres at metaphase, which prevented the chromosomes from being pulled by the fibres and migrating to opposite poles of the cells, leading to incomplete mitosis. 
4. Suzuki, A., Shin, J., Wang, Y., Min, S., Poncz, M., Choi, J., Discher, D., Carpenter, C., Lian, L., Zhao, L., Wang, Y. and Abrams, C. (2013). RhoA Is Essential for Maintaining Normal Megakaryocyte Ploidy and Platelet Generation. PLoS ONE, 8(7), p.e69315.
RhoA, an intracellular signaling protein, was proved to play important role in the development of megakaryocytes. In the experiment, it was found that RhoA-negative megakaryocytes were larger, contained higher numbers of chromosomes (ploidy), and were rapidly releasing immature, unstable platelets which were immediately discarded by the circulation system. RhoA-positive cells (control) showed normal maturation speed and completed development of platelets before their release. 
Lab 3 Assessment
Paper 1 Ng et al. investigated the actions of Thrombopoietin (TPO) on megakaryocytes via the Mpl receptor. It was discovered that TPO binding onto the Mpl receptors causes dimerization of the receptors and a targeted cell response to stabilize megakaryocyte cell numbers. However, it was also discovered that TPO action on Mpl receptors led to the stimulation and production of proplatelets. Ng et al., employed techniques involving the use of green fluorescent protein expressed on mice Mpl alleles to more accurately observe the actions of the Mpl locus. It was then concluded that the presence of Mpl receptors on megakaryocytes was crucial for the regulating the megakaryocyte population.
Khetawat et al. examined the expression of estrogen receptor (ER), estrogen receptor (ER ), progesterone receptor (PR) and androgen receptor (AR) within the megakaryocytic lineage. Samples of megakaryocytes were obtained and generated ex vivo from human donor stem cells. It was discovered that these samples contained ER, RNA and AR. The seconda major finding showed that both “ER and AR transcripts are up-regulated during megakaryocyte differentiation”(Khetawat et al., 2000). Hormonal influence also played a part in the expresseion of AR. ER protein was shown to be greatest in the cytoplasm in glycoprotein llb+ megakaryocytes through immunofluorescence microscopy. The occurrence of AR and ER was observed in platelets via western immunoblotting.
Rozmyslowicz et al.  studied platelets and megakaryocyte- derived microparticles (MP) to determine whether the expression or abesnce of receptors led to HIV infection. It was discovered that cells expressing CD4 and virus co-receptors were susceptible to infection. It was also discovered that it may be due to other mechanisms played a role in infection such as the transfer of HIV entry receptors between cells by MP.
Bender et al.  observed the role dynamin played relating to vesicle transport and endocytosis in human thrombocytes. Bender et al. studied the megakaryocytes of mice lacking DNM2. It was discovered that a lack of DMN2 was lethal as megakaryocyte membrane formation and thrombopoiesis as dependent on DMN2 shown by high-resolution immunofluorescence confocal microscopy.
- Regulatation of skeletal homoeostasis by megakaryocyte secretions
- HSC quiescence in the bone marrow due to megakaryocytes
- Production of platelets from megakaryocytes
- Platelet roles such as thrombus formation
<pubmed>26557683</pubmed> Due to the great similarities between erythroid and thrombocytic, this article seeks to demonstrate the differentiation between the erythroid and thrombocytic as they evolved overtime from a single ancestral linage. This article compares the thousands of platelets per one megakaryocyte that is in the mammalian as opposed to nonmammalian thrombocytes which are much smaller and more flexible. Hematopoiesis suggests that mammalian megakaryocytic and erythrocytic cells probably evolved to increase their biological performance such as oxygen transport and homostasis, ultimately being an improvement of their ancestral cells. There is evidence found that the megakaryocytes are likely evolved as thrombocytic improvement. This is derived from the characteristics of the relationships between the zebrafish hamatopoietic progenitors and the mapping of their proliferation kinetics. Additionally despite the striking phenotypic differences between the megakaryocytes of the mammalian and nonmammalian thrombocytes, there is a distinct link between mammalian and nonmammalian erythroid and thrombocytic cells in terms of their molecular control and their proliferation potential.
This article can be used in describing the development of the megakaryocyte and how it evolved and the similarities it has to nonmammalian thrombocytes. 
<pubmed>11012198</pubmed> This paper highlights the structure and function of megakaryocytes (MK) and platelets and how they are not identical. MK is unique for its enormous size and polyploidy. MK cells also produce their progeny cells called platelets via a mechanism called cytoplasmic fragmentation. It should be noted that platelets have no nucleus and usually lack ribosomes however they have a well defined structure. MK cells undergo endomitoses where the chromosomal DNA reduplicates to an average ploidy of 16 N while the cytoplasm never divides. During this process the nuclear membrane disappear, thus allowing for free exchange between nucleoplasm and cytoplasm. Further this article tackles the important concepts of when a MK matures and what happens; the platelet territories become separated within the MK cytoplasm, the separated membrane system is made up of a blend of membranes that are from different sources, before fragmentation happens the peripheral zone of the cell is absent of organelles, the organelles- free peripheral zone may unpremeditatedly form large veils or blebs and finally the fragmentation of MK is best observed when the cells are fixed in suspension. It is imperative to note that although the platelet membrane is demarcated within the cytoplasm of the MK cell, it is wrong to assume that the surface membrane of the platelet is identical. Additionally it can be seen that antigenic epitopes found on platelets may not be found on MK even though it stands to reason that there is a considerable antigenic cross-reactivity.
This article has proven to be important in the structure and function sub heading in the group research as it highlights the characteristics of a MK cell while addressing the similarities and the link it has to platelets. 
<pubmed>10468153</pubmed> The article demonstrates the understanding of the structure and the function of a megakaryocyte. It explains that MK cells are known to be large polyploidy cells that are mostly located in the bone marrow. The main role of the Mk cell is to maintain normal blood platelet count by releasing platelets from the mature MK cells. Mk cells can be divided into highly proliferative MK burst forming cells or MK colony- forming cells. Through evidence it can be seen that at the end of the proliferative phase the Mk precursors undergo transformation in the cell due to the increase in ploidy thanks to the process of endomitosis. Endomitotic division is characterized by DNA replication and nuclear segmentation. The maturation of MK cells is driven by the emergence and appearance in MK’s cytoplasm which contains specific organelles and the precursors of important platelet structures. The knock out mouse models have shown to be extensively functional in the delineation in the capacity of growth factors, their receptors, and transcription factors in Mk differentiation. P45-NFE2 is a transcription factor that has proven to be essential for MK cytoplasmic development due to NFE2-/- mice fail to produce platelets even though the present MK cells are normally located in the bone marrow.
This article has proven to be effective enough to include in the subheading Structure and function as it addresses both headings in detail and includes pathology. It describes cytokine effect on MK development, proplatelet formation and transendothelial migration of MK cells. 
<pubmed>11012205</pubmed> This article address some studies that report a hierarchy of hematopietic cells that are competent of producing MKs cloned from both Adult bone marrow (ABM) and fetal bone marrow (FBM). The studies of in vitro megakaryocytopoiesis helped produce a hierarchy of MK progenitor cells. The hierarchy begins with the hematopoietic stem cells due to the presence of thromboproietin (TPO) alone produce MKs. The BFU-MK is a primative progenitor cell committed to the megakaryocytic linage. The properties of the BFU-MK allow it to be readily distinguished from the more differentiatied MK progenitor cell, the colony-forming unit- megakaryocyte (CFU-MK). The primitive HPPC-MK, BFU-MK and the highly differentiated CFU-MK cells are known as MK progenitor cells that’s are lineage- restricted. In the FBM a significant number of oligopotent hematopoietic progentitor cells are cabale in vitro of producing colonies composed of many hematopoietic linages including a subpopulation of MKs. It is still unknown the contributions of these mixed lineages progentior cells to megakayocyopiesis and the growth factors responsible for their in vivo development. It can be seen in the experiment that human bone marrow cells showed to express CD34 but not HLA-DR (which is known to contain a high amounts of hematopoiectic stem cells) was competent in developing MK progenitors cells for 10 weeks in the presence of various cytokine combinations.
This article fits under the subheading structure as it targets the structure of the MK cells and the factors and the lineages associated with MK cells. Further this article tackles the commitment of pluripotent hematopoietic stem cells to the Lineage of MK cells and the changes in the MK progenitor cells. 
Z3489355 (talk) 20:10, 14 April 2016 (AEST) I'm currently working on megakaryopoiesis. The articles related to it are much scarcer than those about production of platelets, unfortunately. So I think it will take a bit more time to find the appropriate references.
Z5020043 (talk) 22:51, 20 April 2016 (AEST) J: Hey guys, so for the "Special Features" part, since I will be researching mainly about the receptors found on megakaryocytes, should I research info and briefly write about a few different receptors or just mainly focus on one type of receptor e.g. the Mpl receptor and talk about the consequences in relation to abnormal TPO levels?
Z5020175 (talk) 12:59, 21 April 2016 (AEST) M: Hi guys, Mark has suggested that a timeline is good for the history, for structure we should: include picture showing size and morphology, for development: Histological slides that show the different stages of MK development
Z5017493 (talk) 13:04, 21 April 2016 (AEST) T: I have done work on history and pathology. Will upload when I get access to the document. I have to convert my paragraphs into a timeline for history and will discuss with Jaclyn the two main diseases of MK/platelets
Z3330991 (talk) 15:48, 24 April 2016 (AEST) Nadine; https://books.google.com.au/books?id=a1estSuaQ6kC&pg=PA293&lpg=PA293&dq=megakaryocytes+structure&source=bl&ots=2XcoS1Nfmt&sig=XkXoXfdQmWG4yqbzQbV--kTffnI&hl=en&sa=X&ved=0ahUKEwjaitvWv6bMAhVEx6YKHZF4CjUQ6AEIkAEwEw#v=onepage&q=megakaryocytes%20structure&f=false
the link above is for a book that i think is great, you guys can use it as a resource for our group project. you'll find that on page 292-305 of the text book it focuses on MEGAKARYOCYTES
Z3330991 (talk) 21:45, 25 April 2016 (AEST) Nadine; Guys this week i'd like for us to have all information up on the page before this time next week. Doesn't have to be the finished product, it can be dot points and just copy and paste parts of articles that you will use with reference and that way you can reword it and have the reference already there. I will edit my section tomorrow morning hopefully. Also as i was reading papers and websites i just added two sentences to the intro section. Doesn't have to be used but its there now, we can delete or include it , up to you guys. Let me know how everything on your end is going.
Z3489355 (talk) 23:05, 27 April 2016 (AEST) Hi guys, I've added most of the main points in megakaryocyte development. I still feel I can expand it further though, so I will add more in pretty soon. I actually also feel our figure/image about the development uploaded by Matthew should be put in this section as well, to give a better flow to the page, rather than jumping to the next section and revisit the same information previously detailed. But let me know if you guys have any other ideas :)
Z5017493 (talk) 08:59, 28 April 2016 (AEST) T: I will upload my portion of the history once I get to university as the wifi is awful where I live. Only portions are uploading and it's skipping on entire sections.
- Banner Image
- Table for structure - comparing megakaryocytes to platelets
- Drawing for TPO signalling
- Brainstorm of megakaryocyte functions
- Drawing for platelet plug formation
- Add in a few more diseases: Maybe add in 1 more bone disorder
- Add in histological slides
- Add in references
- Please put down which aspects you are doing! I will be doing the Brainstorm & Drawing for platelet plug
Z5017493 (talk) 12:00, 28 April 2016 (AEST) T: I will be designing the Banner image and upload it for K to add to the page. I will also be doing the overall editing of the page to ensure everything flows and is unified. (We're doing great stuff but I feel like its somewhat stilted just because we're different people) I will be doing a GlossIary/Definitions list I will also be adding some external links about pathology and history for people to do further readings if they wish it. I suggest you guys add some too.
Z5020043 (talk) 12:06, 28 April 2016 (AEST) J: I've put some info for the receptors, right now they're just dot points but as I research more I'll make proper paragraphs out of them. I will also be drawing a diagram for TPO:MPL signalling as well as forming a table about the different types of secretions and mediators involved with megkaryocytes. Lastly, I will also add on to what we already have for the future of megakaryocytes.
Z3330991 (talk) 12:10, 4 May 2016 (AEST)Nadine; hi guys, I've dramatically cut out and left the relevant information on my section. However in saying that i know i need to add an image or get a drawing of the structure of megakaryocytes or platelets to help with the understanding of the content. Also I'm hoping to somehow format the structure part into a table that allows for easier understanding of the structure of both plateles and MK cells while addressing the similarities and the differences.
Z5020043 (talk) 12:26, 4 May 2016 (AEST) J: So far I've finalised the info for CAMT and the TPO:c-Mpl signalling pathway. I have also drawn a diagram that explains this pathway and inserted it on the page. I will now gather information about the future of megakaryocytes and put it on the page later tonight. I will also try to insert a collapsable table for mediators formed and involved with megakaryocytes.
Z5017493 (talk) 14:32, 4 May 2016 (AEST) T: Hey guys, I'll be putting up the banner tonight, editing before tomorrow's lab, and adding my work thus far. I'll also e adding some images, for the sake of aesthetics and to give our peer reviewers a greater visual aspect to improve the understanding of the visual learners here. Glossary is being worked on as I speak/type!
Z5020043 (talk) 22:22, 4 May 2016 (AEST) J: As of now I have uploaded a diagram a drew of haemostasis and vascular. Tomorrow I'll decide whether its necessary or not to put in a table for the mediators formed and involved with megakaryocytes.
Z5020175 (talk) 11:39, 5 May 2016 (AEST) M: Hi guys, good job on what we have so far! So last night Jaclyn and I had discussed redoing the banner & we have decided to add a signalling bit. I also edited the wording of different sections. Here are a list of things that I feel our page should add:
- Tables - Structure and signalling
- Graphs - Possibily in Pathology
- More diseases
- table for the structure
- image for structure
Please put your peer reviews here
The page is good, but the main problem is a consistent misuse or no use of proper referencing. Here are my observations: - Unreferenced statements thrombopoetin section - ET references box is not technically referred to so it’s a bibliography not a reference - Glossary is unfinished - History is fully unreferenced - “Megakaryocytes have been shown to maintain HSC quiescence during homeostasis “ i think this would read better if it was written "in homeostatic conditions" - I like the figures but they have very little text information. Figure 4 could discuss in more detail the 4 branches of the mind map of MK functions. - Good job inserting the essential thrombocytosis video but I would put it under the Essential thrombocyte title not the “pathology” title seeing as it’s specific to one pathology. - For consistency I would ensure that all acronyms are uppercase (in CAMT subsection of pathology some acronyms aren’t in uppercase. Also you use the acronym TPO several times and describe it several times. You could reduce the wordiness by just doing this once. - Needs a reread through for minor spelling checks as well
- <pubmed> 26557683 </pubmed>
- <pubmed> 26557683 </pubmed>