DYNAMIC REGULATION OF MITOCHONDRIAL STAT3 AND ITS ASSOCIATION WITH CYPD

In recent years, a number of nuclear transcription factors have been shown to be present in the mitochondria where they have distinct roles in regulating mitochondrial function. Signal Transducer and Activator of Transcription 3 (STAT3), classically activated by the JAK family of receptor associated tyrosine kinases to drive nuclear gene expression, is one such transcription factor with a unique mitochondrial role. There, it has been shown to support oxidative phosphorylation, regulate mitochondrial-encoded transcripts, and be key for the transformation and growth of a number of different cancers. Despite its well-characterized functional importance at the level of the mitochondria, the mechanism through which mitochondrial STAT3 acts and how it is regulated has not been as well studied. Using various cell culture models, we now show that mitochondrial STAT3 is dynamically regulated by oxidative stress and cytokine treatment in the acute setting. Under these conditions we have observed a rapid loss of mitochondrial STAT3 that recovers to baseline conditions with time. During this recovery phase we have noted that mitochondrial STAT3 becomes competent to bind to Cyclophilin D (CypD), the key regulator and activator of the mitochondrial permeability transition pore (MPTP). This is particularly the case with oxidative insults, which we believe may represent an important homeostatic mechanism for the cell. Intriguingly, chronic stimulation with certain stressors seems to increase mitochondrial STAT3 levels suggesting differential regulation in the acute versus chronic setting. The regulation of mitochondrial STAT3 levels by various stimuli points to a novel signaling pathway potentially linking mitochondrial responses with those of the cell. Unification of responses throughout the cell would seem to serve a clear adaptive advantage, particularly in coupling nuclear regulation with metabolic demands as dictated by the mitochondria. Extramitochondrial signaling, also known as the mitochondrial retrograde response, has emerged as an important homeostatic mechanism in lower organisms, but its signaling components have not been well characterized at the mammalian level. Our results point to a role for mitochondrial STAT3 in sensing cellular inputs, whereby its regulation and subsequent association with CypD may have implications in overall mitochondrial quality control. Though the inner workings of this signaling cascade are just beginning to be elucidated, they suggest the existence of a previously unappreciated pathway at the mitochondrial level

Using PLS to understand potential sources of process variation & assessing medium components to alter afucosylation

Understanding potential sources of process performance and product quality variation in a manufacturing process may benefit from the use of multivariate data analysis techniques. PLS analysis identified some potential sources of process performance variation. For products where antibody-dependent cell-mediated cytotoxicity (ADCC) is part of the mechanism of action, total afucoslyated glycans (Afuc) variation may be important. This work was also directed at understanding current process variability for Afuc and the effect of process parameters that may vary during routine production. In addition, a series of small-scale experiments were conducted to screen several medium components for their ability to shift Afuc. Components studied included substrates and co-factors of enzymes involved in the relevant pathways (de novo and salvage production of GDP-fucose and fucosylation). Several medium components were shown be effective for altering levels of Afuc, however the majority of these also resulted in a loss in productivity. Supplementing zinc (Zn) and cobalt (Co) to production culture medium reduced Afuc without negatively impacting process performance

The Emerging Role of CAR T Cell Therapy in Relapsed/Refractory Hodgkin Lymphoma

Treatment for Hodgkin lymphoma (HL) has evolved considerably from the time it was originally described in the 19th century with many patients now being cured with frontline therapy. Despite these advances, upwards of 10% of patients experience progressive disease after initial therapy with an even higher percentage relapsing. Until recently there had been limited therapeutic options for relapsed and/or refractory HL outside of highly intensive chemotherapy with stem cell rescue. Improved understanding of the pathophysiology of HL, coupled with the emergence of more targeted therapeutics, has reshaped how we view the treatment of relapsed/refractory HL and its prognosis. With this, there has been an increased focus on immunotherapies that can reprogram the immune system to better overcome the immunosuppressive milieu found in HL for improved cancer cell killing. In particular, chimeric antigen receptor (CAR) T cells are emerging as a valuable therapeutic tool in this area. Building on the success of antibody-drug conjugates directed against CD30, CAR T cells engineered to recognize the same antigen are now reaching patients. Though still in its infancy, CAR T therapy for relapsed/refractory HL has shown exceptional promise in early-stage clinical trials with the potential for durable responses even in patients who had progressed through multiple lines of prior therapy. Here we will review currently available data on the use of CAR T cells in HL, strategies to optimize their effectiveness, and how this therapy may fit into the treatment paradigm of HL going forward

Determining the Quantitative Principles of T Cell Response to Antigenic Disparity in Stem Cell Transplantation

Alloreactivity compromising clinical outcomes in stem cell transplantation is observed despite HLA matching of donors and recipients. This has its origin in the variation between the exomes of the two, which provides the basis for minor histocompatibility antigens (mHA). The mHA presented on the HLA class I and II molecules and the ensuing T cell response to these antigens results in graft vs. host disease. In this paper, results of a whole exome sequencing study are presented, with resulting alloreactive polymorphic peptides and their HLA class I and HLA class II (DRB1) binding affinity quantified. Large libraries of potentially alloreactive recipient peptides binding both sets of molecules were identified, with HLA-DRB1 generally presenting a greater number of peptides. These results are used to develop a quantitative framework to understand the immunobiology of transplantation. A tensor-based approach is used to derive the equations needed to determine the alloreactive donor T cell response from the mHA-HLA binding affinity and protein expression data. This approach may be used in future studies to simulate the magnitude of expected donor T cell response and determine the risk for alloreactive complications in HLA matched or mismatched hematopoietic cell and solid organ transplantation

Crosslinking Studies of Protein-Protein Interactions in Nonribosomal Peptide Biosynthesis

SummarySelective protein-protein interactions between nonribosomal peptide synthetase (NRPS) proteins, governed by communication-mediating (COM) domains, are responsible for proper translocation of biosynthetic intermediates to produce the natural product. In this study, we developed a crosslinking assay, utilizing bioorthogonal probes compatible with carrier protein modification, for probing the protein interactions between COM domains of NRPS enzymes. Employing the Huisgen 1,3-dipolar cycloaddition of azides and alkynes, we examined crosslinking of cognate NRPS modules within the tyrocidine pathway and demonstrated the sensitivity of our panel of crosslinking probes toward the selective protein interactions of compatible COM domains. These studies indicate that copper-free crosslinking substrates uniquely offer a diagnostic probe for protein-protein interactions. Likewise, these crosslinking probes serve as ideal chemical tools for structural studies between NRPS modules where functional assays are lacking

Stem Cell Transplantation As A Dynamical System: Are Clinical Outcomes Deterministic?

Outcomes in stem cell transplantation (SCT) are modeled using probability theory. However the clinical course following SCT appears to demonstrate many characteristics of dynamical systems, especially when outcomes are considered in the context of immune reconstitution. Dynamical systems tend to evolve over time according to mathematically determined rules. Characteristically, the future states of the system are predicated on the states preceding them, and there is sensitivity to initial conditions. In SCT, the interaction between donor T cells and the recipient may be considered as such a system in which, graft source, conditioning and early immunosuppression profoundly influence immune reconstitution over time. This eventually determines clinical outcomes, either the emergence of tolerance or the development of graft versus host disease. In this paper parallels between SCT and dynamical systems are explored and a conceptual framework for developing mathematical models to understand disparate transplant outcomes is proposed.Comment: 23 pages, 4 figures. Updated version with additional data, 2 new figures and editorial revisions. New authors adde

Persistence, prevalence, and polymorphism of sequelae after COVID-19 in unvaccinated, young adults of the Swiss Armed Forces: a longitudinal, cohort study (LoCoMo)

Background: Persistent COVID-19 sequelae could have global, public health ramifications. We therefore aimed to describe sequelae presenting more than 180 days after COVID-19-focussing on several organ systems, general health, and laboratory parameters-in non-hospitalised, unvaccinated, young adults. Methods: We did a longitudinal cohort study of all army bases in Switzerland. Eligible participants were personnel of the Swiss Armed Forces (SAF) who were aged 18-30 years with a positive or negative RT-PCR test for SARS-CoV-2 during their service between March 1, 2020, and Dec 31, 2020. Exclusion criteria were unwillingness to participate in testing. Females or men with a known reproductive anomaly were excluded from the optional component of male fertility testing. COVID-19 was defined as a positive diagnostic RT-PCR test result for SARS-CoV-2 with concurrent symptoms compatible with COVID-19. Participants were subdivided into four groups: control group (ie, serologically negative), asymptomatic infection group (ie, serologically positive but with no symptoms), non-recent COVID-19 group (>180 days since positive PCR test), and recent COVID-19 group (≤180 days since positive PCR test). Outcomes of interest were part of a comprehensive, intensive test battery that was administered during a single day. The test battery quantified the effect of SARS-CoV-2 infection on cardiovascular, pulmonary, neurological, renal, ophthalmological, male reproductive, psychological, general health, and laboratory parameters. This study was registered with ClinicalTrials.gov, number NCT04942249. Findings: Between May 20, 2021, and Nov 26, 2021, we enrolled 501 participants. 29 (6%) of 501 were female and 464 (93%) were male, and the median age was 21 years (IQR 21-23). Eight (2%) of 501 had incomplete data and were not included into the study groups. 177 participants had previous COVID-19 that was more than 180 days (mean 340 days) since diagnosis (ie, the non-recent COVID-19 group) compared with 251 serologically negative individuals (ie, the control group). We included 19 participants in the recent COVID-19 group and 46 in the asymptomatic infection group. We found a significant trend towards metabolic disorders in participants of the non-recent COVID-19 group compared with those in the control group: higher BMI (median 24·0 kg/m2 [IQR 22·0-25·8] vs 23·2 kg/m2 [27·1-25·0]; p=0·035), lower aerobic threshold (39% [36-43] vs 41% [37-46]; p=0·012), and higher blood cholesterol (4·2 μM [3·7-4·7] vs 3·9 μM [3·5-4·5]; p<0·0001) and LDL concentrations (2·4 μM [1·9-2·9] vs 2·2 μM [1·7-2·7]; p=0·001). The only significant psychosocial difference was found in the results of the Chalder Fatigue scale with the non-recent COVID-19 group reporting higher fatigue scores than the control group (median 12 points [IQR 11-15] vs 11 [9-14]; p=0·027). No significant differences in other psychosocial questionnaire scores, ophthalmological outcomes, and sperm quality or motility were reported between the control group and non-recent COVID-19 group. Interpretation: Young, previously healthy, individuals largely recover from SARS-CoV-2 infection. However, the constellation of higher BMI, dyslipidaemia, and lower physical endurance 180 days after COVID-19 is suggestive of a higher risk of developing metabolic disorders and possible cardiovascular complications. These findings will guide future investigations and follow-up management

Iceberg calving during transition from grounded to floating ice: Columbia Glacier, Alaska

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95521/1/grl27053-sup-0003-fs02.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/95521/2/grl27053-sup-0002-fs01.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/95521/3/grl27053-sup-0005-txts01.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/95521/4/grl27053.pd

Quantum computing with antiferromagnetic spin clusters

We show that a wide range of spin clusters with antiferromagnetic intracluster exchange interaction allows one to define a qubit. For these spin cluster qubits, initialization, quantum gate operation, and readout are possible using the same techniques as for single spins. Quantum gate operation for the spin cluster qubit does not require control over the intracluster exchange interaction. Electric and magnetic fields necessary to effect quantum gates need only be controlled on the length scale of the spin cluster rather than the scale for a single spin. Here, we calculate the energy gap separating the logical qubit states from the next excited state and the matrix elements which determine quantum gate operation times. We discuss spin cluster qubits formed by one- and two-dimensional arrays of s=1/2 spins as well as clusters formed by spins s>1/2. We illustrate the advantages of spin cluster qubits for various suggested implementations of spin qubits and analyze the scaling of decoherence time with spin cluster size.Comment: 15 pages, 7 figures; minor change

Tiny Sc allows the chains to rattle: Impact of Lu and Y doping on the charge density wave in ScV6_6Sn6_6

The kagome metals display an intriguing variety of electronic and magnetic phases arising from the connectivity of atoms on a kagome lattice. A growing number of these materials with vanadium kagome nets host charge density waves (CDWs) at low temperatures including ScV$_6$Sn$_6$, CsV$_3$Sb$_5$, and V$_3$Sb$_2$. Curiously, only the Sc version of the $R$V$_6$Sn$_6$ HfFe$_6$Ge$_6$-type materials hosts a CDW ($R =$Gd-Lu, Y, Sc). In this study we investigate the role of rare earth size in CDW formation in the $R$V$_6$Sn$_6$ compounds. Magnetization measurements on our single crystals of (Sc,Lu)V$_6$Sn$_6$ and (Sc,Y)V$_6$Sn$_6$ establish that the CDW is suppressed by substitution of Sc by larger Lu or Y. Single crystal x-ray diffraction reveals that compressible Sn-Sn bonds accommodate the larger rare earth atoms within loosely packed $R$-Sn-Sn chains without significantly expanding the lattice. We propose that Sc provides the extra room in these chains crucial to CDW formation in ScV$_6$Sn$_6$. Our rattling chain model explains why both physical pressure and substitution by larger rare earths hinder CDW formation despite opposite impacts on lattice size. We emphasize the cooperative effect of pressure and rare earth size by demonstrating that pressure further suppresses the CDW in a Lu-doped ScV$_6$Sn$_6$ crystal. Our model not only addresses why a CDW only forms in the $R$V$_6$Sn$_6$ materials with tiny Sc, it also advances to our understanding of why unusual CDWs form in the kagome metals.Comment: 28 pages, 9 figures, crystallographic information files for LuV6Sn6 and YV6Sn6 along with supplemental materials in ancillary file