Systemic inflammation has been linked to synapse loss and cognitive decline in human patients and animal models. A role for microglial release of pro-inflammatory cytokines has been proposed based on ...in vivo and primary culture studies. However, mechanisms are hard to study in vivo as specific microglial ablation is challenging and the extracellular fluid cannot be sampled without invasive methods. Primary cultures have different limitations as the intricate multicellular architecture in the brain is not fully reproduced. It is essential to confirm proposed brain-specific mechanisms of inflammatory synapse loss directly in brain tissue. Organotypic hippocampal slice cultures (OHSCs) retain much of the in vivo neuronal architecture, synaptic connections and diversity of cell types whilst providing convenient access to manipulate and sample the culture medium and observe cellular reactions.
OHSCs were generated from P6-P9 C57BL/6 mice. Inflammation was induced via addition of lipopolysaccharide (LPS), and cultures were analysed for changes in synaptic proteins, gene expression and protein secretion. Microglia were selectively depleted using clodronate, and the effect of IL1β was assessed using a specific neutralising monoclonal antibody.
LPS treatment induced loss of the presynaptic protein synaptophysin without altering PSD95 or Aβ protein levels. Depletion of microglia prior to LPS application prevented the loss of synaptophysin, whilst microglia depletion after the inflammatory insult was partially effective, although less so than pre-emptive treatment, indicating a time-critical window in which microglia can induce synaptic damage. IL1β protein and mRNA were increased after LPS addition, with these effects also prevented by microglia depletion. Direct application of IL1β to OHSCs resulted in synaptophysin loss whilst pre-treatment with IL1β neutralising antibody prior to LPS addition prevented a significant loss of synaptophysin but may also impact basal synaptic levels.
The loss of synaptophysin in this system confirms LPS can act directly within brain tissue to disrupt synapses, and we show that microglia are the relevant cellular target when all major CNS cell types are present. By overcoming limitations of primary culture and in vivo work, our study strengthens the evidence for a key role of microglia-derived IL1β in synaptic dysfunction after inflammatory insult.
The primary aim was to determine the prognostic significance of apoptosis in colorectal tumour cells and tumour-associated stroma. A secondary aim was to determine whether apoptosis was related to ...immune surveillance.
Immunohistochemistry was performed using monoclonal antibodies recognising cleaved caspase-3 (CC3), cleaved poly (ADP-ribose) polymerase (PARP), p53, Bcl2, MHC-II, B cells (CD16), macrophages (CD68) and T cells (CD3), on a tissue microarray of 462 colorectal tumours.
Kaplan-Meier analysis demonstrated that patients with high expression of CC3 in the tumour or CC3 or cleaved PARP in tumour-associated stroma have a good prognosis. This suggests that tumour stroma is promoting tumourigenesis and that high levels of death within the stroma breaks this link. CC3 levels in the tumour correlated with cleaved PARP and MHC-II expression but not with CD16, CD68, CD3, p53 or Bcl2 expression. CC3 levels on tumour-associated stroma also correlated with cleaved PARP and MHC-II expression but not with CD16, CD68, CD3, p53 or Bcl2 expression. Tumour cells express MHC-II in response to IFN-γ, suggesting that this may be one of the initiators of apoptosis within the good prognosis tumours. Although 73% of the MHC-II-positive tumour had high levels of apoptosis, many tumours had high levels of apoptosis in the absence of MHC-II, implying that this is only one of many causes of apoptosis within tumours. On multivariate analysis, using Cox's proportional hazards model, tumour stage, vascular invasion and expression of CC3 in tumour-associated stroma were shown to be independent markers of prognosis.
This study shows that a high level of apoptosis within colorectal tumour-associated stroma is an independent marker of good prognosis.
Summary Background Interleukin 6 mediates graft-versus-host disease (GVHD) in experimental allogeneic stem-cell transplantation (allogeneic SCT) and represents an attractive therapeutic target. We ...aimed to assess whether the humanised anti-interleukin-6 receptor monoclonal antibody, tocilizumab, could attenuate the incidence of acute GVHD. Methods We undertook a single-group, single-institution phase 1/2 study at the Royal Brisbane and Women's Hospital Bone Marrow Transplantation unit, QLD, Australia. Eligible patients were 18–65 years old and underwent T-replete HLA-matched allogeneic SCT with either total body irradiation-based myeloablative or reduced-intensity conditioning from unrelated or sibling donors. One intravenous dose of tocilizumab (8 mg/kg, capped at 800 mg, over 60 mins' infusion) was given the day before allogeneic SCT along with standard GVHD prophylaxis (cyclosporin 5 mg/kg per day on days −1 to +1, then 3 mg/kg per day to maintain therapeutic levels (trough levels of 140–300 ng/mL) for 100 days plus methotrexate 15 mg/m2 on day 1, then 10 mg/m2 on days 3, 6, and 11). The primary endpoint was incidence of grade 2–4 acute GVHD at day 100, assessed and graded as per the Seattle criteria. Immunological profiles were compared with a non-randomised group of patients receiving allogeneic SCT, but not treated with tocilizumab. This trial is registered with the Australian and New Zealand Clinical Trials Registry, number ACTRN12612000726853. Findings Between Jan 19, 2012, and Aug 27, 2013, 48 eligible patients receiving cyclosporin and methotrexate as GVHD prophylaxis were enrolled into the study. The incidence of grade 2–4 acute GVHD in patients treated with tocilizumab at day 100 was 12% (95% CI 5–24), and the incidence of grade 3–4 acute GVHD was 4% (1–13). Grade 2–4 acute GVHD involving the skin developed in five (10%) patients of 48 treated with tocilizumab, involving the gastrointestinal tract in four (8%) patients; there were no reported cases involving the liver. Low incidences of grade 2–4 acute GVHD were noted in patients receiving both myeloablative total body irradiation-based conditioning (12% 95% CI 2–34) and fludarabine and melphalan reduced-intensity conditioning (12% 4–27). Immune reconstitution was preserved in recipients of interleukin-6 receptor inhibition, but qualitatively modified with suppression of known pathogenic STAT3-dependent pathways. Interpretation Interleukin 6 is the main detectable and dysregulated cytokine secreted after allogeneic SCT and its inhibition is a potential new and simple strategy to protect from acute GVHD despite robust immune reconstitution; a randomised, controlled trial assessing tocilizumab in addition to standard GVHD prophylaxis in these patients is warranted. Funding National Health and Medical Research Council and Queensland Health.
With recent poaching of southern white rhinoceros (SWR
) reaching record levels, the need for a robust assurance population is urgent. However, the global captive SWR population is not currently ...self-sustaining due to the reproductive failure of captive-born females. Dietary phytoestrogens have been proposed to play a role in this phenomenon, and recent work has demonstrated a negative relationship between diet estrogenicity and fertility of captive-born female SWR. To further examine this relationship, we compared gut microbial communities, fecal phytoestrogens, and fertility of SWR to those of another rhinoceros species-the greater one-horned rhinoceros (GOHR
), which consumes a similar diet but exhibits high levels of fertility in captivity. Using 16S rRNA amplicon sequencing and mass spectrometry, we identified a species-specific fecal microbiota and three dominant fecal phytoestrogen profiles. These profiles exhibited various levels of estrogenicity when tested in an
estrogen receptor activation assay for both rhinoceros species, with profiles dominated by the microbial metabolite equol stimulating the highest levels of receptor activation. Finally, we found that SWR fertility varies significantly not only with respect to phytoestrogen profile, but also with respect to the abundance of several bacterial taxa and microbially derived phytoestrogen metabolites. Taken together, these data suggest that in addition to species differences in estrogen receptor sensitivity to phytoestrogens, reproductive outcomes may be driven by the gut microbiota's transformation of dietary phytoestrogens in captive SWR females.
Southern white rhinoceros (SWR) poaching has reached record levels, and captive infertility has rendered SWR assurance populations no longer self-sustaining. Previous work has identified dietary phytoestrogens as a likely cause of this problem. Here, we investigate the role of gut microbiota in this phenomenon by comparing two rhinoceros species to provide the first characterizations of gut microbiomes for any rhinoceros species. To our knowledge, our approach, combining parallel sequencing, mass spectrometry, and estrogen receptor activation assays, provides insight into the relationship between microbially mediated phytoestrogen metabolism and fertility that is novel for any vertebrate species. With this information, we plan to direct future work aimed at developing strategies to improve captive reproduction in the hope of alleviating their threat of extinction.
Tau and amyloid beta (Aβ) are the prime suspects for driving pathology in Alzheimer’s disease (AD) and, as such, have become the focus of therapeutic development. Recent research, however, shows that ...these proteins have been highly conserved throughout evolution and may have crucial, physiological roles. Such functions may be lost during AD progression or be unintentionally disrupted by tau- or Aβ-targeting therapies. Tau has been revealed to be more than a simple stabiliser of microtubules, reported to play a role in a range of biological processes including myelination, glucose metabolism, axonal transport, microtubule dynamics, iron homeostasis, neurogenesis, motor function, learning and memory, neuronal excitability, and DNA protection. Aβ is similarly multifunctional, and is proposed to regulate learning and memory, angiogenesis, neurogenesis, repair leaks in the blood–brain barrier, promote recovery from injury, and act as an antimicrobial peptide and tumour suppressor. This review will discuss potential physiological roles of tau and Aβ, highlighting how changes to these functions may contribute to pathology, as well as the implications for therapeutic development. We propose that a balanced consideration of both the physiological and pathological roles of tau and Aβ will be essential for the design of safe and effective therapeutics.
Pregnancy determination is difficult in the giant panda (Ailuropoda melanolecua), representing a challenge for ex situ conservation efforts. Research in other species experiencing pseudopregnancy ...indicates that urinary/fecal concentrations of 13,14, dihydro-15-keto-prostaglandin F2α (PGFM) can accurately determine pregnancy status. Our objective was to determine if urinary PGFM concentrations are associated with pregnancy status in the giant panda. Urinary PGFM concentrations were measured in female giant pandas (n = 4) throughout gestation (n = 6) and pseudopregnancy (n = 4) using a commercial enzyme immunoassay. Regardless of pregnancy status, PGFM excretion followed a predictable pattern: 1) baseline concentrations for 11-19 weeks following ovulation; 2) a modest, initial peak 14-36 days after the start of the secondary urinary progestagen rise; 3) a subsequent period of relatively low concentrations; and 4) a large, terminal peak at the end of the luteal phase. Pregnant profiles were distinguished by an earlier initial peak (P = 0.024), higher inter-peak concentrations (P < 0.001), and a larger terminal peak (P = 0.003) compared to pseudopregnancy profiles. Parturition occurred 23 to 25 days from the initial PGFM surge and within 24 hours of the start of the terminal increase. These pattern differences indicate that urinary PGFM monitoring can be used to predict pregnancy status and time parturition in the giant panda. Furthermore, this is the only species known to exhibit a significant PGFM increase during pseudopregnancy, suggesting a unique physiological mechanism for regulating the end of the luteal phase in the giant panda.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Investigated cortisol awakening response (CAR) in 103 healthy males.•CACNA1C rs1006737 genotype mediated the effects of early adversity on CAR.•Higher CAR in non-risk genotype carriers may indicate ...a more resilient HPA axis.•More pronounced genotype-trauma interaction when stress experienced prior to adolescence.
The rs1006737 (A/G) single nucleotide polymorphism within the gene encoding the Cav1.2 subunit of the L-type voltage-dependent calcium channel (CACNA1C) has been strongly implicated in psychiatric disorders. In addition, calcium channels are sensitive to the effects of glucocorticoids and functional variation may contribute to altered stress responsivity. This study aimed to investigate the role of early life stress (ELS) and its interaction with CACNA1C rs1006737 in affecting the cortisol awakening response (CAR), an indicator of HPA-axis function. Salivary cortisol was measured in 103 healthy adult males (aged 21–63) on two consecutive days at awakening and 30 min later. The ELS measure investigated self-reported adverse life events prior to age 17. The results revealed a marginally significant main effect of CACNA1C, a significant main effect of ELS, and a significant genotype-by-ELS interaction on the CAR, whereby non-risk allele carriers (GG) who had experienced early adversity showed higher CAR compared to the other groups. Further exploratory analyses showed that this interaction may have arisen from individuals who had experienced ELS before adolescence (prior to age 13). This study is the first to provide evidence that the effect of ELS on CAR may be partially moderated via CACNA1C rs1006737 genotype, whereby the heightened CAR in the GG-ELS group may be an indicator of mental health resilience in response to ELS.
Synaptic degeneration in Alzheimer disease Tzioras, Makis; McGeachan, Robert I; Durrant, Claire S ...
Nature reviews. Neurology,
01/2023, Letnik:
19, Številka:
1
Journal Article
Recenzirano
Alzheimer disease (AD) is characterized by progressive cognitive decline in older individuals accompanied by the presence of two pathological protein aggregates - amyloid-β and phosphorylated tau - ...in the brain. The disease results in brain atrophy caused by neuronal loss and synapse degeneration. Synaptic loss strongly correlates with cognitive decline in both humans and animal models of AD. Indeed, evidence suggests that soluble forms of amyloid-β and tau can cause synaptotoxicity and spread through neural circuits. These pathological changes are accompanied by an altered phenotype in the glial cells of the brain - one hypothesis is that glia excessively ingest synapses and modulate the trans-synaptic spread of pathology. To date, effective therapies for the treatment or prevention of AD are lacking, but understanding how synaptic degeneration occurs will be essential for the development of new interventions. Here, we highlight the mechanisms through which synapses degenerate in the AD brain, and discuss key questions that still need to be answered. We also cover the ways in which our understanding of the mechanisms of synaptic degeneration is leading to new therapeutic approaches for AD.
All extant species in the Rhinocerotidae family are experiencing escalating threats in the wild, making self‐sustaining captive populations essential genetic reservoirs for species survival. Assisted ...reproductive technologies (ARTs) will become increasingly important for achieving and maintaining ex situ population sustainability and genetic diversity. Previous reports have shown that a large proportion of captive southern white rhinoceros (SWR) females are irregularly cyclic or acyclic, and that cycling females display two different estrous cycle lengths of approximately 30 or 70 days. It has been suggested that the longer estrous cycle length is infertile or subfertile, as no term pregnancies have been observed following long cycles. Here we report the achievement of two pregnancies following long luteal phases, using ovulation induction and artificial insemination with either fresh or frozen‐thawed semen. One female SWR conceived on the first insemination attempt and gave birth to a live offspring. A second female conceived twice in consecutive long cycles although the first embryo was resorbed by 33 days post‐insemination. A pregnancy from this female's second insemination is ongoing with expected parturition in November 2019. Whether prolonged estrous cycles in SWR are subfertile or infertile in natural breeding situations remains unclear. However, our findings demonstrate that the application of ARTs following prolonged cycles can result the successful establishment of pregnancies in SWR. Therefore, with ARTs, female SWR otherwise considered nonreproductive due to long estrous cycles may still have the potential for representation and contribution to the ex situ population.
Research Highlights
Two pregnancies were achieved following long luteal phases in two southern white rhinoceros females.
We provide evidence that long luteal phases are not necessarily infertile or early pregnancy loss.
A fundamental property of infectious agents is their particulate nature: infectivity arises from independently-acting particles rather than as a result of collective action. Assemblies of the protein ...tau can exhibit seeding behaviour, potentially underlying the apparent spread of tau aggregation in many neurodegenerative diseases. Here we ask whether tau assemblies share with classical pathogens the characteristic of particulate behaviour. We used organotypic hippocampal slice cultures from P301S tau transgenic mice in order to precisely control the concentration of extracellular tau assemblies in neural tissue. Whilst untreated slices displayed no overt signs of pathology, exposure to recombinant tau assemblies could result in the formation of intraneuronal, hyperphosphorylated tau structures. However, seeding ability of tau assemblies did not titrate in a one-hit manner in neural tissue. The results suggest that seeding behaviour of tau arises at high concentrations, with implications for the interpretation of high-dose intracranial challenge experiments and the possible contribution of seeded aggregation to human disease.
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