Pancreas-derived mesenchymal stromal cells share immune response-modulating and angiogenic potential with bone marrow mesenchymal stromal cells and can be grown to therapeutic scale under GMP conditions

Background aims: Mesenchymal stromal cells (MSCs) isolated from various tissues are under investigation as cellular therapeutics in a wide range of diseases. It is appreciated that the basic biological functions of MSCs vary depending on tissue source. However, in-depth comparative analyses between MSCs isolated from different tissue sources under Good Manufacturing Practice (GMP) conditions are lacking. Human clinical-grade low-purity islet (LPI) fractions are generated as a byproduct of islet isolation for transplantation. MSC isolates were derived from LPI fractions with the aim of performing a systematic, standardized comparative analysis of these cells with clinically relevant bone marrow-derived MSCs (BM MSCs). Methods: MSC isolates were derived from LPI fractions and expanded in platelet lysate-supplemented medium or in commercially available xenogeneic-free medium. Doubling rate, phenotype, differentiation potential, gene expression, protein production and immunomodulatory capacity of LPIs were compared with those of BM MSCs. Results: MSCs can be readily derived in vitro from non-transplanted fractions resulting from islet cell processing (i.e., LPI MSCs). LPI MSCs grow stably in serum-free or platelet lysate-supplemented media and demonstrate in vitro self-renewal, as measured by colony-forming unit assay. LPI MSCs express patterns of chemokines and pro-regenerative factors similar to those of BM MSCs and, importantly, are equally able to attract immune cells in vitro and in vivo and suppress T-cell proliferation in vitro. Additionally, LPI MSCs can be expanded to therapeutically relevant doses at low passage under GMP conditions. Conclusions: LPI MSCs represent an alternative source of GMP MSCs with functions comparable to BM MSCs

Late Winter Biogeochemical Conditions Under Sea Ice in the Canadian High Arctic

With the Arctic summer sea-ice extent in decline, questions are arising as to how changes in sea-ice dynamics might affect biogeochemical cycling and phenomena such as carbon dioxide (CO2) uptake and ocean acidification. Recent field research in these areas has concentrated on biogeochemical and CO2 measurements during spring, summer or autumn, but there are few data for the winter or winter–spring transition, particularly in the High Arctic. Here, we present carbon and nutrient data within and under sea ice measured during the Catlin Arctic Survey, over 40 days in March and April 2010, off Ellef Ringnes Island (78° 43.11′ N, 104° 47.44′ W) in the Canadian High Arctic. Results show relatively low surface water (1–10 m) nitrate (<1.3 µM) and total inorganic carbon concentrations (mean±SD=2015±5.83 µmol kg−1), total alkalinity (mean±SD=2134±11.09 µmol kg−1) and under-ice pCO2sw (mean±SD=286±17 µatm). These surprisingly low wintertime carbon and nutrient conditions suggest that the outer Canadian Arctic Archipelago region is nitrate-limited on account of sluggish mixing among the multi-year ice regions of the High Arctic, which could temper the potential of widespread under-ice and open-water phytoplankton blooms later in the season

An immune dysfunction score for stratification of patients with acute infection based on whole-blood gene expression

Dysregulated host responses to infection can lead to organ dysfunction and sepsis, causing millions of global deaths each year. To alleviate this burden, improved prognostication and biomarkers of response are urgently needed. We investigated the use of whole-blood transcriptomics for stratification of patients with severe infection by integrating data from 3149 samples from patients with sepsis due to community-acquired pneumonia or fecal peritonitis admitted to intensive care and healthy individuals into a gene expression reference map. We used this map to derive a quantitative sepsis response signature (SRSq) score reflective of immune dysfunction and predictive of clinical outcomes, which can be estimated using a 7- or 12-gene signature. Last, we built a machine learning framework, SepstratifieR, to deploy SRSq in adult and pediatric bacterial and viral sepsis, H1N1 influenza, and COVID-19, demonstrating clinically relevant stratification across diseases and revealing some of the physiological alterations linking immune dysregulation to mortality. Our method enables early identification of individuals with dysfunctional immune profiles, bringing us closer to precision medicine in infection.peer-reviewe

Synthesis and reactions of titanium-nitrogen multiple bonds

This Thesis reports the synthesis and reactions of new hydrazide, alkoxyimide and benzimidamide complexes (L)Ti=NX (X = NAr2, NOtBu or C(Ar)NOtBu; L = dianionic supporting ligand or ligand set). The work is supported by DFT calculations which are used to rationalise the reaction outcomes observed and, in one case, the bonding in alkoxyimide complexes. Chapter One provides a background to hydrazide complexes, starting with their relevance to nitrogen fixation. In addition, Group 4 imide, alkylidene hydrazide and alkoxyimide complexes are also reviewed. The Chapter focuses in particular on the synthesis, structure, and stoichiometric and catalytic reactions of these complexes with unsaturated substrates. Chapter Two describes the development of the virtually unexplored 1,2-diamination reaction. The substrate scope and isolation of the vinylamine products are discussed. The protonation of the vinylimide complex Ti(N2NMe){NC(Ph)C(Me)NPh2}(py) and the overall diamination reaction itself is then explored through an in-depth experimental and computational study. Chapter Three details the synthesis of cyclopentadienyl-amidinate supported alkoxyimide complexes. The first detailed reactivity study, supported by structural and computational studies, of any alkoxyimide complex is reported. Novel reactivity at Ti=Nα and, in one instance, Nα–Oβ reductive bond cleavage is observed. Chapter Four describes the reactivity of the benzimidamide complex Cp*Ti{PhC(NiPr)2}{NC(ArF5)NOtBu} with a range of substrates including heterocumulenes, aldehydes, isonitriles and B(ArF5)3. Novel reactivity at Ti=Nα, and 3-component coupling is presented, and the experimental results supported by structural and computational studies. Chapter Five presents full experimental procedures and characterising data for the new complexes reported.This thesis is not currently available in ORA

Reactions of Titanium Imides and Hydrazides with Boranes

International audienceWe report the first reactions of titanium imido, alkylidene hydrazido, and dimethylhydrazido compounds with theboranes H 2 BTex, 9-BBN, HBAr F2 , and HBPin (Tex = tert-hexyl; Ar F = C 6 F 5 ). Reactions of Cp*Ti{MeC(N i Pr) 2 }(NTol) withH 2 BTex, 9-BBN, or HBAr F2 resulted in the hydride-bridged adducts Cp*Ti{MeC(N i Pr 2 ) 2 }{N(Tol)HBRR′} without B−H bondcleavage. Cp*Ti{MeC(N i Pr) 2 }(NNCPh 2 ) (4) reacted with HBAr F2 via a sequence of steps involving adducts at the β- and thenα-nitrogen of the NNCPh 2 ligand, before slow 1,2-addition of B−H across the NCPh 2 double bond of 4, formingCp*Ti{MeC(N i Pr) 2 }{NN(BAr F2 )CHPh 2 } (17). The other boranes reacted immediately with 4 to form homologues of 17.These products are the first examples of borylhydrazido(2-) complexes. Reaction of Cp*Ti{MeC(N i Pr 2 ) 2 }(NNMe 2 ) (2) withHBAr F2 gave the hydride-bridged adduct Cp*Ti{MeC(N i Pr 2 ) 2 }{N(NMe 2 )HBAr F2 }, whereas with HBPin B−H bond cleavageoccurred to form the borylhydrazide(1-)-hydride Cp*Ti{MeC(N i Pr) 2 }(H){N(BPin)NMe 2 }. Finally, reaction of 2 with 9-BBNdimer resulted in H 2 elimination and formation of Me 2 NBC 8 H 14 and Cp*Ti{MeC(N i Pr) 2 }(NBC 8 H 14 ), a rare example of aborylimido compound

Synthesis, Bonding and Reactivity of a Terminal Titanium Alkylidene Hydrazido Compound

International audienceWe report a detailed study of the reactions of the TiNNCPh2 alkylidene hydrazide functional group in [Cp*Ti{MeC(NiPr)2}(NNCPh2)] (8) with a variety of unsaturated and saturated substrates. Compound 8 was prepared from [Cp*Ti{MeC(NiPr)2}(NtBu)] and Ph2CNNH2. DFT calculations were used to determine the nature of the bonding for the TiNNCPh2 moiety in 8 and in the previously reported [Cp2Ti(NNCPh2)(PMe3)]. Reaction of 8 with CO2 gave dimeric [(Cp*Ti{MeC(NiPr)2}{μ-OC(NNCPh2)O})2] and the "double-insertion" dicarboxylate species [Cp*Ti-{MeC(NiPr)2}{OC(O)N(NCPh2)C(O)O}] through an initial [2+2] cycloaddition product [Cp*Ti{MeC(NiPr)2}{N(NCPh2)C(O)O}], the congener of which could be isolated in the corresponding reaction with CS2. The reaction with isocyanates or isothiocyanates tBuNCO or ArNCE (Ar=Tol or 2,6-C6H3iPr2; E=O, S) gave either complete NNCPh2 transfer, [2+2] cycloaddition to TiNα or single- or double-substrate insertion into the TiNα bond. The treatment of 8 with isonitriles RNC (R=tBu or Xyl) formed σ-adducts [Cp*Ti{MeC(NiPr)2}(NNCPh2)(CNR)]. With ArF5CCH (ArF5=C6F5) the [2+2] cycloaddition product [Cp*Ti{MeC(NiPr)2}{N(NCPh2)C(ArF5)C(H)}] was formed, whereas with benzonitriles ArCN (Ar=Ph or ArF5) two equivalents of substrate were coupled in a head-to-tail manner across the TiNα bond to form [Cp*Ti{MeC(NiPr)2}{N(NCPh2)C(Ar)NC(Ar)N}]. Treatment of 8 with RSiH3 (R=aryl or Bu) or Ph2SiH2 gave [Cp*Ti{MeC(NiPr)2}{N(SiHRR′)N(CHPh2)}] (R′=H or Ph) through net 1,3-addition of SiH to the NNCPh2 linkage of 8, whereas reaction with PhSiH2X (X=Cl, Br) led to the TiNα 1,2-addition products [Cp*Ti{MeC(NiPr)2}(X){N(NCPh2)SiH2Ph}]

Reactions of Titanium Hydrazides with Silanes and Boranes: N–N Bond Cleavage and N Atom Functionalization

Reaction of Ti­(N₂^iPrN)­(NNPh₂)­(py) with Ph­(R)­SiH₂ (R = H, Ph) or 9-BBN gave reductive cleavage of the N_α–N_β bond and formation of new silyl- or boryl-amido ligands. The corresponding reactions of Cp*Ti­{MeC­(NⁱPr)₂}­(NNR₂) (R = Me or Ph) with HBPin or 9-BBN gave borylhydrazido-hydride or borylimido products, respectively. N_α and N_β atom transfer and dehydrogenative coupling reactions are also reported

Reactions of Titanium Hydrazides with Silanes and Boranes: N–N Bond Cleavage and N Atom Functionalization

Reaction of Ti­(N₂^iPrN)­(NNPh₂)­(py) with Ph­(R)­SiH₂ (R = H, Ph) or 9-BBN gave reductive cleavage of the N_α–N_β bond and formation of new silyl- or boryl-amido ligands. The corresponding reactions of Cp*Ti­{MeC­(NⁱPr)₂}­(NNR₂) (R = Me or Ph) with HBPin or 9-BBN gave borylhydrazido-hydride or borylimido products, respectively. N_α and N_β atom transfer and dehydrogenative coupling reactions are also reported

Synthesis and Reactions of a Cyclopentadienyl-Amidinate Titanium <i>tert-</i>Butoxyimido Compound

We report the first detailed reactivity study of a group 4 alkoxyimido complex, namely Cp*Ti­{PhC­(NⁱPr)₂}­(NO^tBu) (<b>19</b>), with heterocumulenes, aldehydes, ketones, organic nitriles, Ar^F₅CCH, and B­(Ar^F₅)₃ (Ar^F₅ = C₆F₅). Compound <b>19</b> was synthesized via imide/alkoxyamine exchange from Cp*Ti­{PhC­(NⁱPr)₂}­(N^tBu) and ^tBuONH₂. Reaction of <b>19</b> with CS₂ and Ar′NCO (Ar′ = 2,6-C₆H₃ⁱPr₂) gave the [2 + 2] cycloaddition products Cp*Ti­{PhC­(NⁱPr)₂}­{SC­(S)­N­(O^tBu)} and Cp*Ti­{PhC­(NⁱPr)₂}­{N­(O^tBu)­C­(NAr′)­O}, respectively, whereas reaction with 2 equiv of TolNCO afforded Cp*Ti­{PhC­(NⁱPr)₂}­{OC­(NTol)­N­(Tol)­C­(NO^tBu)­O} following a sequence of cycloaddition–extrusion and cycloaddition–insertion steps. Net NO^tBu group transfer was observed with both ^tBuNCO and PhC­(O)­R, yielding the oxo-bridged dimer [Cp*Ti­{PhC­(NⁱPr)₂}­(μ-O)]₂ and either the alkoxycarbodiimide ^tBuNCNO^tBu or the oxime ethers PhC­(NO^tBu)­R (R = H (<b>25a</b>), Me (<b>25b</b>), Ph (<b>25c</b>)). DFT studies showed that in the reaction with PhC­(O)­R (R = H, Me) the product distribution between the <i>syn</i> and <i>anti</i> isomers of PhC­(NO^tBu)­R was under kinetic control. Reaction of <b>19</b> with ArCN gave the TiN_α insertion products Cp*Ti­{PhC­(NⁱPr)₂}­{NC­(Ar)­NO^tBu} (Ar = Ph (<b>28</b>), 2,6-C₆H₃F₂ (<b>27</b>), Ar^F₅ (<b>26</b>)) containing <i>tert</i>-butoxybenzimidamide ligands. Reaction of <b>19</b> or <b>26</b> with an excess of Ar^F₅CN gave Cp*Ti­{PhC­(NⁱPr)₂}­{NC­(Ar^F₅)­NC­(Ar^F₅)­N­(C­{Ar^F₅}­NO^tBu)} (<b>29</b>) following net head-to-tail coupling of 2 equiv of Ar^F₅CN across the TiN_α bond of <b>26</b>. Reductive N_α–O_β bond cleavage was observed with Ar^F₅CCH, forming Cp*Ti­(O^tBu)­{NC­(Ar^F₅)­C­(H)­N­(ⁱPr)­C­(Ph)­N­(ⁱPr)} (<b>30</b>). Addition of 2 equiv of [Et₃NH]­[BPh₄] to <b>19</b> in THF-<i>d</i>₈ resulted in protonolysis of the amidinate ligand, forming [PhC­(NHⁱPr)₂]­[BPh₄] and the cationic alkoxyimido complex [Cp*Ti­(NO^tBu)­(THF-<i>d</i>₈)₂]⁺. In contrast, reaction with B­(Ar^F₅)₃ resulted in elimination of isobutene and formation of Cp*Ti­{PhC­(NⁱPr)₂}­{η²-ON­(H)­B­(Ar^F₅)₃}

Synthesis and Reactions of a Cyclopentadienyl-Amidinate Titanium <i>tert-</i>Butoxyimido Compound

We report the first detailed reactivity study of a group 4 alkoxyimido complex, namely Cp*Ti­{PhC­(NⁱPr)₂}­(NO^tBu) (<b>19</b>), with heterocumulenes, aldehydes, ketones, organic nitriles, Ar^F₅CCH, and B­(Ar^F₅)₃ (Ar^F₅ = C₆F₅). Compound <b>19</b> was synthesized via imide/alkoxyamine exchange from Cp*Ti­{PhC­(NⁱPr)₂}­(N^tBu) and ^tBuONH₂. Reaction of <b>19</b> with CS₂ and Ar′NCO (Ar′ = 2,6-C₆H₃ⁱPr₂) gave the [2 + 2] cycloaddition products Cp*Ti­{PhC­(NⁱPr)₂}­{SC­(S)­N­(O^tBu)} and Cp*Ti­{PhC­(NⁱPr)₂}­{N­(O^tBu)­C­(NAr′)­O}, respectively, whereas reaction with 2 equiv of TolNCO afforded Cp*Ti­{PhC­(NⁱPr)₂}­{OC­(NTol)­N­(Tol)­C­(NO^tBu)­O} following a sequence of cycloaddition–extrusion and cycloaddition–insertion steps. Net NO^tBu group transfer was observed with both ^tBuNCO and PhC­(O)­R, yielding the oxo-bridged dimer [Cp*Ti­{PhC­(NⁱPr)₂}­(μ-O)]₂ and either the alkoxycarbodiimide ^tBuNCNO^tBu or the oxime ethers PhC­(NO^tBu)­R (R = H (<b>25a</b>), Me (<b>25b</b>), Ph (<b>25c</b>)). DFT studies showed that in the reaction with PhC­(O)­R (R = H, Me) the product distribution between the <i>syn</i> and <i>anti</i> isomers of PhC­(NO^tBu)­R was under kinetic control. Reaction of <b>19</b> with ArCN gave the TiN_α insertion products Cp*Ti­{PhC­(NⁱPr)₂}­{NC­(Ar)­NO^tBu} (Ar = Ph (<b>28</b>), 2,6-C₆H₃F₂ (<b>27</b>), Ar^F₅ (<b>26</b>)) containing <i>tert</i>-butoxybenzimidamide ligands. Reaction of <b>19</b> or <b>26</b> with an excess of Ar^F₅CN gave Cp*Ti­{PhC­(NⁱPr)₂}­{NC­(Ar^F₅)­NC­(Ar^F₅)­N­(C­{Ar^F₅}­NO^tBu)} (<b>29</b>) following net head-to-tail coupling of 2 equiv of Ar^F₅CN across the TiN_α bond of <b>26</b>. Reductive N_α–O_β bond cleavage was observed with Ar^F₅CCH, forming Cp*Ti­(O^tBu)­{NC­(Ar^F₅)­C­(H)­N­(ⁱPr)­C­(Ph)­N­(ⁱPr)} (<b>30</b>). Addition of 2 equiv of [Et₃NH]­[BPh₄] to <b>19</b> in THF-<i>d</i>₈ resulted in protonolysis of the amidinate ligand, forming [PhC­(NHⁱPr)₂]­[BPh₄] and the cationic alkoxyimido complex [Cp*Ti­(NO^tBu)­(THF-<i>d</i>₈)₂]⁺. In contrast, reaction with B­(Ar^F₅)₃ resulted in elimination of isobutene and formation of Cp*Ti­{PhC­(NⁱPr)₂}­{η²-ON­(H)­B­(Ar^F₅)₃}