Chloe James

Professor of Hematology, Bordeaux University, Bordeaux University Hospital, Inserm 1034

[Congrès de la SFTH @SFTH_2025]

📢 Le programme du #CFH2024 est en ligne 👉 https://t.co/dxppKRbiGC
A très bientôt à Lille !🍻🍟
@SFTHemostase

[RPTH @RPTHjournal]

🩸💊Are you curious how to manage #DOACS in patients at extremes of body weight, kidney and liver function?

Check out this #RPTHIllustratedReview from @AryaRoopen @czuprynska_j @VictoriaSpeed3 that answers those questions and more!

🔗https://t.co/Bm9WpAkzsL

[RPTH @RPTHjournal]

In vivo microscopy and computational biology reveal that #platelets have different activation states within the thrombus in a laser-induced #thrombosis model #RPTH @chris_dubois13 @julietourn @ecarminita @lydiecrescence @alexandraMaz1 https://t.co/MmjQvQqoBU

[VTE Specialists Network @VSNUK1]

Your 5 minute read for today if you have access to JTH 😊

[Blood Journals Portfolio @BloodPortfolio]

Hemostasis without clot formation: how platelets guard the vasculature in inflammation, infection, and malignancy
https://t.co/JhLn6crJnq #reviewarticle #phagocytesgranulocytesandmyelopoiesis #plateletsandthrombopoiesis #thrombosisandhemostasis #vascularbiology

[Michael Makris @ProfMakris]

Switching frail elderly patients from VKA antagonists to DOACs resulted in a significantly higher rate of bleeding. Dutch RCT published in @circulation. https://t.co/iEoDlVgr7V

[Alessandra Balduini LAB @ABalduiniLab]

Unraveling the hormonal pathway to megakaryocyte well-being: glucocorticoids drive #platelet production by stimulating proplatelet formation.
@mgrodzi https://t.co/EsVg9Li3Dr
Commentary by @ABalduiniLab @ChrisDBuduo https://t.co/C2ZbllBZW4

[RPTH @RPTHjournal]

In this #RPTHMethodological article, Hindle et al have further described the key pre-analytical conditions for multiparameter #platelet flow cytometry to aid in discovery of novel subpopulations. #flowcytometry @Naseem_Lab
Read all about it here: https://t.co/QUaGMiJSrC

[JTH @JTHjournal]

High @altmetric score!
Thromboembolism is a leading cause of death in #cancer patients receiving outpatient chemotherapy
@aakonc @thrombosisday #wtd2023
https://t.co/TgVs8Jmj8p

[Scott Cameron 🏴󠁧󠁢󠁳󠁣󠁴󠁿🇺🇸🫀🩺📟🔬🧫🧬🥋 @2Scottish]

Shear Forces Induced Platelet Clearance Causes Thrombocytopenia. Glad to see this paper. Known for years. Patients on cardiac mechanical assistance (esp VA-ECMO and IABP) not uncommonly have thrombocytopenia. **PLS DO NOT INDISCRIMINATELY ORDER anti—PF4!** https://t.co/zRHqivzkFM

[ESH (Haematology) @ESHaematology]

📣 Highlighting the learning objectives of #ESHMPN2024!
Register here ➡️ https://t.co/3YE3p63STs
10th Translational Research Conference MYELOPROLIFERATIVE NEOPLASMS
🗓️ April 26-28, 2024 in Mandelieu 🇫🇷
Chairs: @jjkiladjian, @rosslevinemd, @jyoti_nangalia
#ESHCONFERENCES #MPNsm

[Sud Ouest Bordeaux @SO_Bordeaux]

Santé. À Bordeaux, comment un concert au profit de Force Hémato peut concrètement aider la médecine
https://t.co/hNF7i2mkXp

[JTH @JTHjournal]

A6: #Thrombosis is underlying ischemic heart disease, ischemic stroke, and #VTE. VTE > hospitalization was 1st cause of disability in low‐income and middle‐income countries. See this article by the @thrombosisday steering committee: https://t.co/Pl3nf4ZpSB #WTDay23 #ClotChat

[SFA @sf_angiogenese]

It s a beautiful start @sf_angiogenese @univbordeaux with a great line of speakers, short com and posters 😎

[Inserm U1034 - Biology of Cardiovascular Diseases @insermU1034]

[CONGRESS] @sf_angiogenese congress start this week ! You can find the program on https://t.co/UixITJWIaN
We can’t wait to meet you there !

[Veera Rajagopal  @doctorveera]

A fascinating work is published today @Nature by Zhang & Zhang et al. on a serendipitous discovery of haemoglobin expression outside the RBC cells--in chondrocytes--and their critical role in keeping our cartilage alive under an oxygen-deprived environment.

https://t.co/DPhuZN1JGE

Our school teachers taught that haemoglobin (Hb) is an oxygen-transporting protein expressed exclusively in the red blood cells. Although there exist occasional sporadic reports of Hb expression outside the RBCs (e.g. neurons, retinal cells etc.), no one would have guessed Hb would play a critical role (required for survival) outside the RBCs.

The discovery
When studying the cartilage growth plate of neonatal mice, the authors noticed eosin-positive structures in the chondrocytes (cartilage cells) that resembled structures seen in RBCs. Out of curiosity, the researchers went on to stain and examine the chondrocytes of different cartilage tissue types both from mice and humans. They realized that no matter the source or species, the cells always displayed eosin-positive structures under the microscope.

The curious researchers were determined to find out what these structures are made of. They carefully dissected these structures out and studied the protein components using mass spectrometry and were surprised to learn the results: the top hits were Hb proteins.

Unable to believe the results, they went on to study the proteins using different methods--western blotting, immunohistochemistry--and every time they ended up with the same results: the cytoplasm of cells was loaded with organelles-like bodies made of haemoglobin proteins. Finally, they came to the realization that Hb is abundantly produced in chondrocytes. They named these cytoplasmic Hb bodies as "Hedy".

Structure of Hedy
The authors studied the structure and formation of Hb bodies floating in the cytoplasm. Are they like an organelle? Do they have a membrane? Through various experiments, the researchers found that the Hedy structures do not have a membrane. The Hb proteins condense together by phase separation to form organelle-like structures in the cytoplasm. This condensation is itself an evolved process, requiring specific sequence structures of the Hb protein.

Globin switching
We know that there are different forms of Hb each expressed during different developmental stages: embryonic, fetal and adult Hb. There exists a sophisticated molecular machinery (which was believed to be RBC-specific) that switches one Hb type to the other at appropriate times. Using gene silencing experiments, the authors were further awestruck to find that the chondrocytes too switched their Hb types from embryonic to fetal to adult stages, just like RBCs!

Regulation of chondrocyte Hb production
It is well known that hypoxia induces Hb production via upregulating hypoxia-inducible factors (HIFs), an evolutionarily conserved molecular mechanism (Nobel Prize 2019; https://t.co/Sifi8LuYIX). But it turned out that chondrocytes have evolved to increase their Hb expression not via HIF proteins, but through a different protein, the same protein that is required for fetal to adult Hb switching: KLF1 (https://t.co/Zn0X8GpYdq).

How important is Hb for chondrocytes?
Such a high Hb expression in chondrocytes with similar globin switching behaviour as RBCs would mean that this Hb is critical for chondrocytes' survival. By deleting the Hbb gene specifically in the chondrocytes, the authors found that without Hb the chondrocytes die killing the animal a few days after birth.

Conclusion
Continuous oxygen supply is a prerequisite for the survival of cells in all tissues. The only way the cells can receive oxygen is through RBCs in the blood, which requires the tissue to be highly vascularized. When demand exceeds the supply, the cells evolve to survive an oxygen-depriving environment.

Muscles evolved to produce their own globin--myoglobin which has a higher affinity to oxygen than Hb thereby withholding O2 during oxygen excess states and releasing it back during oxygen-deprived state (during exercise). Likewise, the brain has its own globin: neuroglobin (https://t.co/6v78zvHajP).

Today, we are learning that cartilage (an avascular tissue), too, has its own globin. But unlike muscle and brain, have evolved to store oxygen not by making a new type of globin but by making just the same type as the ones in RBCs, but with a higher affinity than RBC Hb.

When it comes to fundamental biology, we often assume that we have found everything and then one day a discovery like this drops, hitting us on the head to make us realize that there is a whole universe of hidden biological secrets waiting to be discovered.

Some recent posts:
1. Gene x sex interaction of PNPLA3 I148M variant (https://t.co/RFegHHRS2z)
2. Effect of consanguineous marriage on the risk of common diseases in offsprings (https://t.co/dTkPsl935K)
3. Whole genome vs. Whole exome sequencing. Which is more cost-effective for genetic association studies? (https://t.co/BCwMzw4g16)

[Syndicat des Hospitalo-Universitaires @DesHospitaloU]

@DesHospitaloU demande l'intégration des émoluments hospitaliers dans le SRE (Service des Retraites de l'État), sans avancée, le SHU appellera à la grève de HU à l’occasion des ECOS.

[JTH @JTHjournal]

Mehic et al. demonstrate the need for repeated VWF testing in bleeding patients with VWF levels <80 IU/dL.
@dino_mehic, @Cihan_Ay_MD, @IngridPabinger, @JoGebhart, @MedUni_Wien
https://t.co/24n77xYwav

[JTH @JTHjournal]

Salzmann et al. show that neutrophil extracellular traps are detrimental inducers of tissue damage during respiratory virus infection, but do not contribute to virus clearance.

https://t.co/1BZAmx9ykr

[Chloe James @chloe_james789]

Very happy to share the link to our article « Platelets and neutrophils cooperate to induce increased NETosis in JAK2V617F myeloproliferative neoplasms ». Hope you will enjoy the reading !
@JTHjournal @AlexandreGuy6 @insermU1034 @CHUBordeaux

https://t.co/khFPmJNlrp