Bacteroidota inhibit microglia clearance of amyloid-beta and promote plaque deposition in Alzheimer's disease mouse models.

The gut microbiota and microglia play critical roles in Alzheimer's disease (AD), and elevated Bacteroides is correlated with cerebrospinal fluid amyloid-ß (Aß) and tau levels in AD. We hypothesize that Bacteroides contributes to AD by modulating microglia. Here we show that administering Bacteroides fragilis to APP/PS1-21 mice increases Aß plaques in females, modulates cortical amyloid processing gene expression, and down regulates phagocytosis and protein degradation microglial gene expression. We further show that administering Bacteroides fragilis to aged wild-type male and female mice suppresses microglial uptake of Aß1-42 injected into the hippocampus. Depleting murine Bacteroidota with metronidazole decreases amyloid load in aged 5xFAD mice, and activates microglial pathways related to phagocytosis, cytokine signaling, and lysosomal degradation. Taken together, our study demonstrates that members of the Bacteroidota phylum contribute to AD pathogenesis by suppressing microglia phagocytic function, which leads to impaired Aß clearance and accumulation of amyloid plaques.

Human regulatory memory B cells defined by expression of TIM-1 and TIGIT are dysfunctional in multiple sclerosis.

Background: Regulatory B cells (Bregs) play a pivotal role in suppressing immune responses, yet there is still a lack of cell surface markers that can rigorously identify them. In mouse models for multiple sclerosis (MS), TIM-1 or TIGIT expression on B cells is required for maintaining self-tolerance and regulating autoimmunity to the central nervous system. Here we investigated the activities of human memory B cells that differentially express TIM-1 and TIGIT to determine their potential regulatory function in healthy donors and patients with relapsing-remitting (RR) MS. Methods: FACS-sorted TIM-1+/-TIGIT+/- memory B (memB) cells co-cultured with allogenic CD4+ T cells were analyzed for proliferation and induction of inflammatory markers using flow cytometry and cytokine quantification, to determine Th1/Th17 cell differentiation. Transcriptional differences were assessed by SMARTSeq2 RNA sequencing analysis. Results: TIM-1-TIGIT- double negative (DN) memB cells strongly induce T cell proliferation and pro-inflammatory cytokine expression. The TIM-1+ memB cells enabled low levels of CD4+ T cell activation and gave rise to T cells that co-express IL-10 with IFNγ and IL-17A or FoxP3. T cells cultured with the TIM-1+TIGIT+ double positive (DP) memB cells exhibited reduced proliferation and IFNγ, IL-17A, TNFα, and GM-CSF expression, and exhibited strong regulation in Breg suppression assays. The functional activity suggests the DP memB cells are a bonafide Breg population. However, MS DP memB cells were less inhibitory than HC DP memB cells. A retrospective longitudinal study of anti-CD20 treated patients found that post-treatment DP memB cell frequency and absolute number were associated with response to therapy. Transcriptomic analyses indicated that the dysfunctional MS-derived DP memB/Breg population exhibited increased expression of genes associated with T cell activation and survival (CD80, ZNF10, PIK3CA), and had distinct gene expression compared to the TIGIT+ or TIM-1+ memB cells. Conclusion: These findings demonstrate that TIM-1/TIGIT expressing memory B cell subsets have distinct functionalities. Co-expression of TIM-1 and TIGIT defines a regulatory memory B cell subset that is functionally impaired in MS.

APOE4 impairs the microglial response in Alzheimer's disease by inducing TGFß-mediated checkpoints.

The APOE4 allele is the strongest genetic risk factor for late-onset Alzheimer's disease (AD). The contribution of microglial APOE4 to AD pathogenesis is unknown, although APOE has the most enriched gene expression in neurodegenerative microglia (MGnD). Here, we show in mice and humans a negative role of microglial APOE4 in the induction of the MGnD response to neurodegeneration. Deletion of microglial APOE4 restores the MGnD phenotype associated with neuroprotection in P301S tau transgenic mice and decreases pathology in APP/PS1 mice. MGnD-astrocyte cross-talk associated with ß-amyloid (Aß) plaque encapsulation and clearance are mediated via LGALS3 signaling following microglial APOE4 deletion. In the brains of AD donors carrying the APOE4 allele, we found a sex-dependent reciprocal induction of AD risk factors associated with suppression of MGnD genes in females, including LGALS3, compared to individuals homozygous for the APOE3 allele. Mechanistically, APOE4-mediated induction of ITGB8-transforming growth factor-ß (TGFß) signaling impairs the MGnD response via upregulation of microglial homeostatic checkpoints, including Inpp5d, in mice. Deletion of Inpp5d in microglia restores MGnD-astrocyte cross-talk and facilitates plaque clearance in APP/PS1 mice. We identify the microglial APOE4-ITGB8-TGFß pathway as a negative regulator of microglial response to AD pathology, and restoring the MGnD phenotype via blocking ITGB8-TGFß signaling provides a promising therapeutic intervention for AD.

Tumor immunogenicity dictates reliance on TCF1 in CD8+ T cells for response to immunotherapy.

Stem-like CD8+ T cells are regulated by T cell factor 1 (TCF1) and are considered requisite for immune checkpoint blockade (ICB) response. However, recent findings indicate that reliance on TCF1+CD8+ T cells for ICB efficacy may differ across tumor contexts. We find that TCF1 is essential for optimal priming of tumor antigen-specific CD8+ T cells and ICB response in poorly immunogenic tumors that accumulate TOX+ dysfunctional T cells, but is dispensable for T cell priming and therapy response in highly immunogenic tumors that efficiently expand transitory effectors. Importantly, improving T cell priming by vaccination or by enhancing antigen presentation on tumors rescues the defective responses of TCF1-deficient CD8+ T cells upon ICB in poorly immunogenic tumors. Our study highlights TCF1's role during the early stages of anti-tumor CD8+ T cell responses with important implications for guiding optimal therapeutic interventions in cancers with low TCF1+CD8+ T cells and low-neo-antigen expression.

Vγ1 and Vγ4 gamma-delta T cells play opposing roles in the immunopathology of traumatic brain injury in males.

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality. The innate and adaptive immune responses play an important role in the pathogenesis of TBI. Gamma-delta (γδ) T cells have been shown to affect brain immunopathology in multiple different conditions, however, their role in acute and chronic TBI is largely unknown. Here, we show that γδ T cells affect the pathophysiology of TBI as early as one day and up to one year following injury in a mouse model. TCRδ-/- mice are characterized by reduced inflammation in acute TBI and improved neurocognitive functions in chronic TBI. We find that the Vγ1 and Vγ4 γδ T cell subsets play opposing roles in TBI. Vγ4 γδ T cells infiltrate the brain and secrete IFN-γ and IL-17 that activate microglia and induce neuroinflammation. Vγ1 γδ T cells, however, secrete TGF-ß that maintains microglial homeostasis and dampens TBI upon infiltrating the brain. These findings provide new insights on the role of different γδ T cell subsets after brain injury and lay down the principles for the development of targeted γδ T-cell-based therapy for TBI.

Preserved T cell but attenuated antibody response in MS patients on fingolimod and ocrelizumab following 2nd and 3rd SARS-CoV-2 mRNA vaccine.

Background: There is limited knowledge about T cell responses in patients with multiple sclerosis (MS) after 3 doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine. Objectives: Assess the SARS-CoV-2 spike antibody and T cell responses in MS patients and healthy controls (HCs) after 2 doses (2-vax) and 3 doses (3-vax) of SARS-CoV-2 mRNA vaccination. Methods: We studied seroconversion rates and T cell responses by flow cytometry in HC and MS patients on fingolimod or ocrelizumab. Results: After 2-vax, 8/33 (24.2%) patients in ocrelizumab group, 5/7 (71.4%) in fingolimod group, and 29/29 (100%) in HC group (P = 5.7 × 10-11) seroconverted. After 3-vax, 9/22 (40.9%) patients in ocrelizumab group, 19/21 (90.5%) in fingolimod group, and 7/7 (100%) in HC group seroconverted (P = 0.0003). The percentage of SARS-CoV-2 peptide reactive total CD4+ T cells increased in HC and ocrelizumab group but not in fingolimod group after 2-vax and 3-vax (P < 0.0001). The percentage of IFNγ and TNFα producing total CD4+ and CD8+ T cells increased in fingolimod group as compared to HC and ocrelizumab group after 2-vax and 3-vax (P < 0.0001). Conclusions: MS patients on ocrelizumab and fingolimod had attenuated humoral responses, but preserved cytokine producing T cell responses compared to HCs after SARS-CoV-2 mRNA vaccination. Clinical Trials Registration: NCT05060354.

Mapping Processes in the Emergency Department Using the Functional Resonance Analysis Method.

Emergency departments (EDs) are dynamic, complex, and demanding environments. Introducing changes that lead to improvements in EDs can be challenging owing to the high staff turnover and mix, high patient volume with different needs, and being the front door to the hospital for the sickest patients. Quality improvement is a methodology applied routinely in EDs to instigate change to improve several outcomes such as waiting times, time to definitive treatment, and patient safety. Introducing the changes needed to transform the system in this way is seldom straightforward with the risk of "not seeing the forest for the trees" when attempting to change the system. In this article, we demonstrate how the functional resonance analysis method can be used to capture the experiences and perceptions of frontline staff to identify the key functions in the system (the trees), to understand the interactions and dependencies between them to make up the ED ecosystem ("the forest") and to support quality improvement planning, identifying priorities and patient safety risks.

microRNA-92a promotes CNS autoimmunity by modulating the regulatory and inflammatory T cell balance.

A disequilibrium between immunosuppressive Tregs and inflammatory IL-17-producing Th17 cells is a hallmark of autoimmune diseases, including multiple sclerosis (MS). However, the molecular mechanisms underlying the Treg and Th17 imbalance in CNS autoimmunity remain largely unclear. Identifying the factors that drive this imbalance is of high clinical interest. Here, we report a major disease-promoting role for microRNA-92a (miR-92a) in CNS autoimmunity. miR-92a was elevated in experimental autoimmune encephalomyelitis (EAE), and its loss attenuated EAE. Mechanistically, miR-92a mediated EAE susceptibility in a T cell-intrinsic manner by restricting Treg induction and suppressive capacity, while supporting Th17 responses, by directly repressing the transcription factor Foxo1. Although miR-92a did not directly alter Th1 differentiation, it appeared to indirectly promote Th1 cells by inhibiting Treg responses. Correspondingly, miR-92a inhibitor therapy ameliorated EAE by concomitantly boosting Treg responses and dampening inflammatory T cell responses. Analogous to our findings in mice, miR-92a was elevated in CD4+ T cells from patients with MS, and miR-92a silencing in patients' T cells promoted Treg development but limited Th17 differentiation. Together, our results demonstrate that miR-92a drives CNS autoimmunity by sustaining the Treg/Th17 imbalance and implicate miR-92a as a potential therapeutic target for MS.

Myeloid cell subsets that express latency-associated peptide promote cancer growth by modulating T cells.

Myeloid suppressor cells promote tumor growth by a variety of mechanisms which are not fully characterized. We identified myeloid cells (MCs) expressing the latency-associated peptide (LAP) of TGF-ß on their surface and LAPHi MCs that stimulate Foxp3+ Tregs while inhibiting effector T cell proliferation and function. Blocking TGF-ß inhibits the tolerogenic ability of LAPHi MCs. Furthermore, adoptive transfer of LAPHi MCs promotes Treg accumulation and tumor growth in vivo. Conversely, anti-LAP antibody, which reduces LAPHi MCs, slows cancer progression. Single-cell RNA-Seq analysis on tumor-derived immune cells revealed LAPHi dominated cell subsets with distinct immunosuppressive signatures, including those with high levels of MHCII and PD-L1 genes. Analogous to mice, LAP is expressed on myeloid suppressor cells in humans, and these cells are increased in glioma patients. Thus, our results identify a previously unknown function by which LAPHi MCs promote tumor growth and offer therapeutic intervention to target these cells in cancer.

Subdiaphragmatic Renal Ectopia: Case Report and Review of the Literature.

Background. We report the case of a male infant whose right kidney migrated to an ectopic position after birth. The migration of a kidney in postnatal life without any symptoms has not been reported in literature so far. Case Presentation. In a series of antenatal and the first postnatal ultrasound scans, the right kidney was normally located within the right renal fossa. During the first 3 months of life, the kidney migrated to a subdiaphragmatic position. This was confirmed on MRI scan. The infant was asymptomatic with normal renal function and blood pressure. Conclusion. Postnatal migration of a kidney has been described in cases of diaphragmatic hernia or nephroptosis. In this report, we describe a case of kidney migration where there were no underlying anatomical defects to provide an explanation for the kidney migration. This is the first report in literature of a case of postnatal migration of a kidney.

Positive trends in paediatric renal biopsy service provision in the UK: a national survey and re-audit of paediatric renal biopsy practice.

BACKGROUND: Paediatric renal biopsy standards introduced in the UK in 2010 were intended to reduce variation and improve practice. A concurrent national drive was aimed at building robust paediatric nephrology networks to ensure services cater for the needs of the family and minimise time away from home. We aimed to identify current national practice since these changes on behalf of the British Association for Paediatric Nephrology. METHODS: All UK paediatric nephrology centres were invited to complete a survey of their biopsy practice, including advance preparation. From 1 January to 30 June 2012, a national prospective audit of renal biopsies was undertaken at participating centres comparing practice with the British Association for Paediatric Nephrology (BAPN) standards and audit results from 2005. RESULTS: Survey results from 11 centres demonstrated increased use of pre-procedure information leaflets (63.6 % vs 45.5 %, P = 0.39) and play preparation (90.9 % vs 9.1 %, P = 0.0001). Audit of 331 biopsies showed a move towards day-case procedures (49.5 % vs 32.9 %, P = 0.17) and reduced major complications (4.5 % vs 10.4 %, P = 0.002). Biopsies with 18-gauge needles had significantly higher mean pass rates (3.2 vs 2.3, P = 0.0008) and major complications (15.3 % vs 3.3 %, P = 0.0015) compared with 16-gauge needles. CONCLUSIONS: Percutaneous renal biopsy remains a safe procedure in children, thus improving family-centered service provision in the UK.

Red colored IgG4 caused by vitamin B12 from cell culture media combined with disulfide reduction at harvest.

While many antibody therapeutics are formulated at low concentration (~10-20 mg/mL) for intravenous administration, high concentration (> 100 mg/mL) formulations may be required for subcutaneous delivery in certain clinical indications. For such high concentration formulations, product color is more apparent due to the higher molecular density across a given path-length. Color is therefore a product quality attribute that must be well-understood and controlled, to demonstrate process consistency and enable clinical trial blinding. Upon concentration of an IgG4 product at the 2000 L manufacturing scale, variability in product color, ranging from yellow to red, was observed. A small-scale experimental model was developed to assess the effect of processing conditions (medium composition and harvest conditions) on final bulk drug substance (BDS) color. The model was used to demonstrate that, for two distinct IgG4 products, red coloration occurred only in the presence of disulfide reduction-mediated antibody dissociation. The red color-causing component was identified as vitamin B 12, in the hydroxocobalamin form, and the extent of red color was correlated with the cobalt (vitamin B 12) concentration in the final pools. The intensity of redness in the final BDS was modulated by changing the concentration of vitamin B 12 in the cell culture media.

Urinary concentration defects and mechanisms underlying nephronophthisis.

The cystic kidney disease nephronophthisis (NPHP) is the commonest genetic cause of end-stage renal failure in young people and children. Histologically the disease is characterized by interstitial fibrosis, tubular atrophy with corticomedullary cyst development and disruption of the tubular basement membrane. Affected children present with polydipsia and polyuria, secondary to a urinary concentration defect, before these structural changes develop. Recently, molecular genetic advances have identified several genes mutated in NPHP, providing novel insights into its pathophysiology for the first time in decades. Here we review the normal physiological mechanisms of urinary concentration and explain, in the context of recent discoveries, the possible mechanisms underlying urinary concentration defects in patients with NPHP. The pattern of a ciliary and adherens junction subcellular localization of nephrocystin proteins is discussed. Recent animal models of cystic kidney disease and treatment with vasopressin V2 receptor antagonists are reviewed and a hypothesis regarding urinary concentration defects in NPHP is proposed. Understanding the cellular mechanisms underlying NPHP and other cystic kidney diseases will provide the rationale for therapeutic interventions in this disease. Early urinary concentration defects provide both a clue to clinical diagnosis of NPHP and potential therapeutic targets for pharmacological treatment of this condition.

Minimising changes in plasma calcium and magnesium concentrations during plasmapheresis.

Hypocalcaemic tetany is a known complication of plasmapheresis. It has two causes. Intravenously administered 4.5% human albumin solution (HAS) has no calcium or magnesium, so the replacement of plasma with this fluid depletes these ions. The citrate in fresh frozen plasma (FFP) chelates divalent cations, so the exchange with this at the end reduces the proportion of calcium and magnesium that is ionised. We studied the effect of supplementing HAS with 2 mmol/l calcium chloride and 0.8 mmol/l magnesium sulphate on the changes in ionised and total calcium and magnesium concentrations throughout plasmapheresis. The supplements prevented the falls in these concentrations that is otherwise seen during the HAS infusion, and, thus, the transient fall in ionised calcium concentration induced by the citrate in the FFP was not so profound, reaching 0.92 instead of 0.78 mmol/l (P = 0.002). Supplementation with calcium and magnesium during HAS maintains their balance and prevents tetany during the FFP infusion.

Acute hydrothorax complicating peritoneal dialysis.

AIM: To determine whether gradually increasing the peritoneal dialysate fill volume from 10 to 40 mL/kg over 6 days, rather than commencing at 40 mL/kg, prevents hydrothorax in children and reverses it if present. METHODS: A review of children peritoneally dialyzed in a single center. RESULTS: During the 20 years beginning June 1985, 416 children were peritoneally dialyzed, of which 327 (79%) had acute and 89 had end-stage renal failure. Among 253 children who had gradually increasing fill volumes, none developed acute hydrothoraces, but 13/163 (8%) who began with 40 mL/kg cycles did (p < 0.000, Fisher's exact test). These were diagnosed after a median (range) of 48 (6-72) hours and were predominantly right sided. Initially, we readily abandoned peritoneal dialysis; 2 were changed to hemodialysis. Subsequently, we found that peritoneal dialysis could be continued by using small volumes with the patients sitting up; cycle volumes were then gradually increased again. One pre-term baby died soon after developing an acute hydrothorax. One patient on chronic peritoneal dialysis developed an acute hydrothorax after forceful vomiting, but recovered after being dialyzed sitting up with low fills. CONCLUSION: Acute hydrothorax can be prevented and treated using graduated cycle volumes, and is not a contraindication for peritoneal dialysis.

Inhibitory effect(s) of polymeric black tea polyphenols on the formation of B(a)P-derived DNA adducts in mouse skin.

The biological activities and chemopreventive properties of green tea polyphenols have been demonstrated, while similar information regarding newly formed major polymeric polyphenols in black tea are not available. Cancer chemoprevention may be achieved by the inhibition of any stage of carcinogenesis. In the present study, we investigated the anti-initiating effects of five polymeric black tea polyphenol (PBP) fractions, by determining their effects on the formation of [3H]-B(a)P-derived DNA adducts as well as the activity of cytochrome P-450 isozymes CYP 1A1 and 1A2 in vitro employing rat liver microsomes. PBP 1-3 inhibited both the microsome catalyzed [3H]-B(a)P-derived DNA adduct formation as well as the activity of CYP 1A1 and 1A2 as assessed by the decreased formation of resorufin from the respective substrates. Further investigation revealed that topical pretreatment(s) of mice with PBP 1-5 (200 mug/day x 4) resulted in a significant decrease in the levels of single topical B(a)P (1 mg/mouse) - induced DNA adducts in epidermal DNA determined by employing 32P-post labeling analysis. Overall, our results suggest that black tea-derived PBPs have one of the chemopreventive properties shown by monomeric green tea polyphenols.