Oxidized SOD1 accelerates cellular senescence in neural stem cells

BACKGROUND

Neural stem cells (NSCs), especially human NSCs, undergo cellular senescence characterized by an irreversible proliferation arrest and loss of stemness after prolonged culture. While compelling correlative data have been generated to support the oxidative stress theory as one of the primary determinants of cellular senescence of NSCs, a direct cause-and-effect relationship between the accumulation of oxidation-mediated damage and cellular senescence of NSCs has yet to be firmly established. Human SOD1 (hSOD1) is susceptible to oxidation. Once oxidized, it undergoes aberrant misfolding and gains toxic properties associated with age-related neurodegenerative disorders. The present study aims to examine the role of oxidized hSOD1 in the senescence of NSCs.

METHODS

NSCs prepared from transgenic mice expressing the wild-type hSOD1 gene were maintained in culture through repeated passages. Extracellular vesicles (EVs) were isolated from culture media at each passage. To selectively knock down oxidized SOD1 in NSCs and EVs, we used a peptide-directed chaperone-mediated protein degradation system named CT4 that we developed recently.

RESULTS

In NSCs expressing the hSOD1 from passage 5, we detected a significant increase of oxidized hSOD1 and an increased expression of biomarkers of cellular senescence, including upregulation of P53 and SA-β-Gal and cytoplasmic translocation of HMGB1. The removal of oxidized SOD1 remarkably increased the proliferation and stemness of the NSCs. Meanwhile, EVs derived from senescent NSCs carrying the wild-type hSOD1 contained high levels of oxidized hSOD1, which could accelerate the senescence of young NSCs and induce the death of cultured neurons. The removal of oxidized hSOD1 from the EVs abolished their senescence-inducing activity. Blocking oxidized SOD1 on EVs with the SOD1 binding domain of the CT4 peptide mitigated its toxicity to neurons.

CONCLUSION

Oxidized hSOD1 is a causal factor in the cellular senescence of NSCs. The removal of oxidized hSOD1 is a strategy to rejuvenate NSCs and to improve the quality of EVs derived from senescent cells.

[The effect of glucose-6-phosphate dehydrogenase deficiency on allogeneic hematopoietic stem cell transplantation in patients with hematological disorders]

Objectives: To determine the effect of glucose-6-phosphate-dehydrogenase (G6PD) deficiency on patients' complications and prognosis following allogeneic stem cell hematopoietic transplantation (allo-HSCT) . Methods: 7 patients with G6PD deficiency (study group) who underwent allo-HSCT at Peking University People's Hospital from March 2015 to January 2021 were selected as the study group, and thirty-five patients who underwent allo-HSCT during the same period but did not have G6PD deficiency were randomly selected as the control group in a 1∶5 ratio. Gender, age, underlying diseases, and donors were balanced between the two groups. Collect clinical data from two patient groups and perform a retrospective nested case-control study. Results: The study group consisted of six male patients and one female patient, with a median age of 37 (range, 2-45) years old. The underlying hematologic diseases included acute myeloid leukemia (n=3), acute lymphocytic leukemia (n=2), and severe aplastic anemia (n=2). All 7 G6PD deficiency patients achieved engraftment of neutrophils within 28 days of allo-HSCT, while the engraftment rate of neutrophils was 94.5% in the control group. The median days of platelet engraftment were 21 (6-64) d and 14 (7-70) d (P=0.113). The incidence rates of secondary poor graft function in the study group and control group were 42.9% (3/7) and 8.6% (3/35), respectively (P=0.036). The CMV infection rates were 71.4% (5/7) and 31.4% (11/35), respectively (P=0.049). The incidence rates of hemorrhagic cystitis were 57.1% (4/7) and 8.6% (3/35), respectively (P=0.005), while the bacterial infection rates were 100% (7/7) and 77.1% (27/35), respectively (P=0.070). The infection rates of EBV were 14.3% (1/7) and 14.3% (5/35), respectively (P=1.000), while the incidence of fungal infection was 14.3% (1/7) and 25.7% (9/35), respectively (P=0.497). The rates of post-transplant lymphoproliferative disease (PTLD) were 0% and 5.7%, respectively (P=0.387) . Conclusions: The findings of this study indicate that blood disease patients with G6PD deficiency can tolerate conventional allo-HSCT pretreatment regimens, and granulocytes and platelets can be implanted successfully. However, after transplantation, patients should exercise caution to avoid viral infection, complications of hemorrhagic cystitis, and secondary poor graft function.

ALS-linked SOD1 mutations impair mitochondrial-derived vesicle formation and accelerate aging

Oxidative stress (OS) is regarded as the dominant theory for aging. While compelling correlative data have been generated to support the OS theory, a direct cause-and-effect relationship between the accumulation of oxidation-mediated damage and aging has not been firmly established. Superoxide dismutase 1 (SOD1) is a primary antioxidant in all cells. It is, however, susceptible to oxidation due to OS and gains toxic properties to cells. This study investigates the role of oxidized SOD1 derived from amyotrophic lateral sclerosis (ALS) linked SOD1 mutations in cell senescence and aging. Herein, we have shown that the cell line NSC34 expressing the G93A mutation of human SOD1 (hSOD1G93A) entered premature senescence as evidenced by a decreased number of the 5-ethynyl-2'-deoxyuridine (EdU)-positive cells. There was an upregulation of cellular senescence markers compared to cells expressing the wild-type human SOD1 (hSOD1WT). Transgenic mice carrying the hSOD1G93A gene showed aging phenotypes at an early age (135 days) with high levels of P53 and P16 but low levels of SIRT1 and SIRT6 compared with age-matched hSOD1WT transgenic mice. Notably, the levels of oxidized SOD1 were significantly elevated in both the senescent NSC34 cells and 135-day hSOD1G93A mice. Selective removal of oxidized SOD1 by our CT4-directed autophagy significantly decelerated aging, indicating that oxidized SOD1 is a causal factor of aging. Intriguingly, mitochondria malfunctioned in both senescent NSC34 cells and middle-aged hSODG93A transgenic mice. They exhibited increased production of mitochondrial-derived vesicles (MDVs) in response to mild OS in mutant humanSOD1 (hSOD1) transgenic mice at a younger age; however, the mitochondrial response gradually declined with aging. In conclusion, our data show that oxidized SOD1 derived from ALS-linked SOD1 mutants is a causal factor for cellular senescence and aging. Compromised mitochondrial responsiveness to OS may serve as an indicator of premature aging.

[Clinical features and risk factors for invasive fungal sinusitis after allogeneic hematopoietic stem cell transplantation]

Objective: To analyze the clinical characteristics and outcomes of patients with invasive fungal sinusitis (invasive fungal rhinosinusitis, IFR) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and explored the risk factors for IFR after allo-HSCT. Methods: Nineteen patients with IFR after allo-HSCT at Peking University People's Hospital from January 2012 to December 2021 were selected as the study group, and 95 patients without IFR after allo-HSCT during this period were randomly selected as the control group (1:5 ratio) . Results: Nineteen patients, including 10 males and 9 females, had IFR after allo-HSCT. The median age was 36 (10-59) years. The median IFR onset time was 68 (9-880) days after allo-HSCT. There were seven patients with acute myeloid leukemia, five with acute lymphoblastic leukemia, two with myelodysplastic syndrome, two with chronic myeloid leukemia, one with acute mixed-cell leukemia, one with multiple myeloma, and one with T-lymphoblastic lymph node tumor. There were 13 confirmed cases and 6 clinically diagnosed cases. The responsible fungus was Mucor in two cases, Rhizopus in four, Aspergillus in four, and Candida in three. Five patients received combined treatment comprising amphotericin B and posaconazole, one patient received combined treatment comprising voriconazole and posaconazole, nine patients received voriconazole, and four patients received amphotericin B. In addition to antifungal treatment, 10 patients underwent surgery. After antifungal treatment and surgery, 15 patients achieved a response, including 13 patients with a complete response and 2 patients with a partial response. Multivariate analysis revealed that neutropenia before transplantation (P=0.021) , hemorrhagic cystitis after transplantation (P=0.012) , delayed platelet engraftment (P=0.008) , and lower transplant mononuclear cell count (P=0.012) were independent risk factors for IFR after allo-HSCT. The 5-year overall survival rates in the IFR and control groups after transplantation were 29.00%±0.12% and 91.00%±0.03%, respectively (P<0.01) . Conclusion: Although IFR is rare, it is associated with poor outcomes in patients undergoing allo-HSCT. The combination of antifungal treatment and surgery might be effective.

[Impact of SARS-CoV-2 infection on graft composition and early transplant outcomes following allogeneic hematopoietic stem cell transplantation]

Objective: To assess the feasibility of using donors with novel coronavirus disease 2019 (COVID-19) for allogeneic hematopoietic stem cell transplantation (allo-HSCT) when there are no other available donors and allo-HSCT cannot be delayed or discontinued. Methods: Seventy-one patients with malignant hematological diseases undergoing allo-HSCT between December 8, 2022, and January 10, 2023, were included. Of these, 16 received grafts from donors with mild COVID-19 (D-COVID(+) group) and 55 received grafts from donors without COVID-19 (D-COVID(-) group). The graft compositions were compared between the two groups. Engraftment, acute graft-versus-host disease (aGVHD), overall survival (OS), and relapse were also evaluated. Results: There were no serious side effects or adverse events in the D-COVID(+) group. The mononuclear cell dose and CD34(+) cell dose were comparable between the two groups, and no additional apheresis was required. There were no significant differences in the lymphocyte, monocyte, and T-cell subset doses between the two groups. The median natural killer cell dose in the D-COVID(+) group was significantly higher than that in the D-COVID(-) group (0.69×10(8)/kg vs. 0.53×10(8)/kg, P=0.031). The median follow-up time was 72 (33-104) days. All patients achieved primary engraftment. The 60-day platelet engraftment rates in the D-COVID(+) and D-COVID(-) groups were 100% and (96.4±0.2) %, respectively (P=0.568). There were no significant differences in neutrophil (P=0.309) and platelet (P=0.544) engraftment times. The cumulative incidence of grade 2-4 aGVHD was (37.5±1.6) % vs. (16.4±0.3) % (P=0.062), and of grade 3-4 aGVHD was 25.0% ±1.3% vs. 9.1% ±0.2% (P=0.095) in the D-COVID(+) and D-COVID(-) groups, respectively. The probabilities of 60-day OS were 100% and 98.1% ±1.8% (P=0.522) in the D-COVID(+) and D-COVID(-) groups, respectively. There was no relapse of primary disease during the study period. Conclusion: When allo-HSCT cannot be delayed or discontinued and no other donor is available, a donor with mild COVID-19 should be considered if tolerable. Larger sample sizes and longer follow-up periods are required to validate these results.

Comparison of Supraclavicular Surgery plus Radiotherapy vs. Radiotherapy Alone in Breast Cancer Patients with Synchronous Ipsilateral Supraclavicular Lymph Node Metastasis: A Multicenter Retrospective Study

PURPOSE/OBJECTIVE(S)

To evaluate and compare the outcomes of supraclavicular lymph node dissection (SLND) plus radiotherapy (RT) and RT alone for patients with synchronous ipsilateral supraclavicular lymph node metastasis (sISLM).

MATERIALS/METHODS

In all, 293 patients with sISLM across three centers were included. Of these, 85 (29.0%) received SLND plus RT and 208 (71.0%) received RT alone. All patients received preoperative systemic therapy followed by mastectomy or lumpectomy and axillary dissection. Supraclavicular recurrence-free survival (SCRFS), locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) were evaluated by using the Kaplan-Meier method and multivariate Cox models. Multiple imputation was used for missing data.

RESULTS

The median follow-up duration of the RT and SLND+RT groups were 53.7 and 63.5 months, respectively. For the RT and SLND+RT groups, the 5-year SCRFS rates were 91.7% vs. 85.5% (P = 0.522), LRRFS rates were 79.1% vs. 73.1% (P = 0.412), DMFS rates were 60.4 vs. 58.8% (P = 0.708), DFS rates were 57.6% vs. 49.7% (P = 0.291), and OS rates were 71.9% vs. 62.2% (P = 0.272), respectively. There was no significant effect on any outcome when comparing SLND+RT versus RT alone in the multivariate analysis. Based on four risk factors of DFS, patients were classified into three risk groups: the intermediate- and high-risk groups had significantly lower survival outcomes than the low-risk group. SLND+RT did not improve outcomes of any risk group compared with RT alone.

CONCLUSION

Patients with sISLM may not benefit from SLND. Distant metastasis remained the major failure pattern, especially for intermediate- and high-risk groups with sISLM may not benefit from SLND. Distant metastasis remained the major failure pattern, especially for intermediate- and high-risk groups.

Selective removal of misfolded SOD1 delays disease onset in a mouse model of amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. There is no cure currently. The discovery that mutations in the gene SOD1 are a cause of ALS marks a breakthrough in the search for effective treatments for ALS. SOD1 is an antioxidant that is highly expressed in motor neurons. Human SOD1 is prone to aberrant modifications. Familial ALS-linked SOD1 variants are particularly susceptible to aberrant modifications. Once modified, SOD1 undergoes conformational changes and becomes misfolded. This study aims to determine the effect of selective removal of misfolded SOD1 on the pathogenesis of ALS.

METHODS

Based on the chaperone-mediated protein degradation pathway, we designed a fusion peptide named CT4 and tested its efficiency in knocking down intracellularly misfolded SOD1 and its efficacy in modifying the pathogenesis of ALS.

RESULTS

Expression of the plasmid carrying the CT4 sequence in human HEK cells resulted in robust removal of misfolded SOD1 induced by serum deprivation. Co-transfection of the CT4 and the G93A-hSOD1 plasmids at various ratios demonstrated a dose-dependent knockdown efficiency on G93A-hSOD1, which could be further increased when misfolding of SOD1 was enhanced by serum deprivation. Application of the full-length CT4 peptide to primary cultures of neurons expressing the G93A variant of human SOD1 revealed a time course of the degradation of misfolded SOD1; misfolded SOD1 started to decrease by 2 h after the application of CT4 and disappeared by 7 h. Intravenous administration of the CT4 peptide at 10 mg/kg to the G93A-hSOD1 reduced human SOD1 in spinal cord tissue by 68% in 24 h and 54% in 48 h in presymptomatic ALS mice. Intraperitoneal administration of the CT4 peptide starting from 60 days of age significantly delayed the onset of ALS and prolonged the lifespan of the G93A-hSOD1 mice.

CONCLUSIONS

The CT4 peptide directs the degradation of misfolded SOD1 in high efficiency and specificity. Selective removal of misfolded SOD1 significantly delays the onset of ALS, demonstrating that misfolded SOD1 is the toxic form of SOD1 that causes motor neuron death. The study proves that selective removal of misfolded SOD1 is a promising treatment for ALS.

Mitochondrial dysfunction in aging

Aging is a complex process that features a functional decline in many organelles. Although mitochondrial dysfunction is suggested as one of the determining factors of aging, the role of mitochondrial quality control (MQC) in aging is still poorly understood. A growing body of evidence points out that reactive oxygen species (ROS) stimulates mitochondrial dynamic changes and accelerates the accumulation of oxidized by-products through mitochondrial proteases and mitochondrial unfolded protein response (UPRmt). Mitochondrial-derived vesicles (MDVs) are the frontline of MQC to dispose of oxidized derivatives. Besides, mitophagy helps remove partially damaged mitochondria to ensure that mitochondria are healthy and functional. Although abundant interventions on MQC have been explored, over-activation or inhibition of any type of MQC may even accelerate abnormal energy metabolism and mitochondrial dysfunction-induced senescence. This review summarizes mechanisms essential for maintaining mitochondrial homeostasis and emphasizes that imbalanced MQC may accelerate cellular senescence and aging. Thus, appropriate interventions on MQC may delay the aging process and extend lifespan.

[Developmental effects of TCIPP and TnBP on zebrafish (Danio rerio) embryos]

Objective: To investigate the toxicity of tris (2-chloropropyl) phosphate (TCIPP) and tributyl phosphate (TnBP) on the growth and development of zebrafish embryos, as well as to explore the underlying mechanisms at the transcriptional level. Methods: With zebrafish as a model, two hpf zebrafish embryos were exposed to TCIPP and TnBP (0.1, 1, 10, 100, 500, and 1 000 μmol/L) using the semi-static method, and their rates of lethality and hatchability were determined. The transcriptome changes of 120 hpf juvenile zebrafish exposed to environmentally relevant concentrations of 0.1 and 1 μmol/L were measured. Results: The 50% lethal concentrations (LC₅₀) of TCIPP and TnBP for zebrafish embryos were 155.30 and 27.62 μmol/L (96 hpf), 156.5 and 26.05 μmol/L (120 hpf), respectively. The 72 hpf hatching rates of TCIPP (100 μmol/L) and TnBP (10 μmol/L) were (23.33±7.72)% and (91.67±2.97)%, which were significantly decreased compared with the control group (P<0.05). Transcriptome analysis showed that TnBP had more differential genes (DEGs) than TCIPP, with a dose-response relationship. These DEGs were enriched in 32 pathways in total, including those involved in oxidative stress, energy metabolism, lipid metabolism, and nuclear receptor-related pathways, using the IPA pathway analysis. Among them, three enriched pathways overlapped between TCIPP and TnBP, including TR/RXR activation and CAR/RXR activation. Additionally, DEGs were also mapped onto pathways of LXR/RXR activation and oxidative stress for TnBP exposure only. Conclusion: Both TCIPP and TnBP have growth and developmental toxicities in zebrafish embryos, with distinct biomolecular mechanisms, and TnBP has a stronger effect than TCIPP.

Carbon monoxide preconditioning is mediated via activation of mitochondrial-derived vesicles

Preconditioning with inhalative carbon monoxide (CO) at low concentrations provides protection against hypoxic and ischemic insults in the brain and heart. The present study aims to test a hypothesis that activation of mitochondrial-derived vesicles (MDVs) is a mechanism underlying the protective effect of CO preconditioning. Here we show that CO preconditioning induced mild oxidative stress and activated massive production of MDVs. Short exposure to a low concentration of carbon monoxide-releasing molecule 2 (CORM-2), a donor of carbon monoxide, prevented oligodendrocyte precursor cells (OPCs) from subsequent death induced by high doses of CO, and protected Chinese hamster ovary (CHO) cells against oxygen-glucose deprivation (OGD)-induced cell death. Furthermore, inhibition of lysosomal activity prevented degradation of MDVs, abolished MDV-mediated mitochondrial quality control, and diminished the protective effect of CO preconditioning. Altogether, our data provide direct evidence suggesting that MDV-mediated mitochondrial quality control may have a novel role in CO preconditioning.

SERS "hot spot" enhance-array assay for misfolded SOD1 correlated with white matter lesions and aging

Misfolding of superoxide dismutase-1 (SOD1) has been correlated with many neurodegenerative diseases, such as Amyotrophic lateral sclerosis's and Alzheimer's among others. However, it is unclear whether misfolded SOD1 plays a role in another neurodegenerative disease of white matter lesions (WMLs). In this study, a sensitive and specific method based on SERS technique was proposed for quantitative detection of misfolded SOD1 content in WMLs. To fabricate the double antibodysandwich substrates for SERS detection, gold nanostars modified with capture antibody were immobilized on glass substrates to prepare active SERS substrates, and then SERS probes conjugated with a Raman reporter and a specific target antibody were coupled with active SERS substrates. This SERS substrates had been employed for quantitative detection of misfolded SOD1 levels in WMLs and exhibited excellent stability, reliability, and accuracy. Moreover, experimental results indicated that the level of misfolded SOD1 increased with the increase in age and the degree of WMLs. Hence, misfolded SOD1 may be a potential blood marker for WMLs and aging. Meanwhile, SERS-based gold nanostars have great clinical application potential in the screening, diagnosis and treatment of WMLs.

The Initial Myelination in the Central Nervous System

Myelination contributes not only to the rapid nerve conduction but also to axonal insulation and protection. In the central nervous system (CNS), the initial myelination features a multistep process where oligodendrocyte precursor cells undergo proliferation and migration before differentiating into mature oligodendrocytes. Mature oligodendrocytes then extend processes and wrap around axons to form the multilayered myelin sheath. These steps are tightly regulated by various cellular and molecular mechanisms, such as transcription factors (Olig family, Sox family), growth factors (PDGF, BDNF, FGF-2, IGF), chemokines/cytokines (TGF-β, IL-1β, TNFα, IL-6, IFN-γ), hormones (T3), axonal signals (PSA-NCAM, L1-CAM, LINGO-1, neural activity), and intracellular signaling pathways (Wnt/β-catenin, PI3 K/AKT/mTOR, ERK/MAPK). However, the fundamental mechanisms for initial myelination are yet to be fully elucidated. Identifying pivotal mechanisms for myelination onset, development, and repair will become the focus of future studies. This review focuses on the current understanding of how CNS myelination is initiated and also the regulatory mechanisms underlying the process.

Cerebral Ischemic Preconditioning Aggravates Death of Oligodendrocytes

Neurodegeneration can benefit from ischemic preconditioning, a natural adaptive reaction to sublethal noxious stimuli. Although there is growing interest in advancing preconditioning to preserve brain function, preconditioning is not yet considered readily achievable in clinical settings. One of the most challenging issues is that there is no fine line between preconditioning stimuli and lethal stimuli. Here, we show deleterious effect of preconditioning on oligodendrocyte precursor cells (OPCs). We identified Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNIP3), a mitochondrial BH3-only protein specifically involved in OPCs loss after preconditioning. Repeated ischemia stabilized BNIP3 and increased the vulnerability of OPCs to subsequent ischemic events. BNIP3 became mitochondrial-bound and was concurrent with the dysfunction of monocarboxylate transporter 1 (MCT1). Inhibition of BNIP3 by RNAi or necrostatin-1 (Nec-1) and knocking out of BNIP3 almost completely prevented OPCs loss and preserved white matter integrity. Together, our results suggest that the unfavorable effect of BNIP3 on OPCs should be noted for safe development of ischemic tolerance. BNIP3 inhibition appears to be a complementary approach to improve the efficacy of preconditioning for ischemic stroke.

A food-grade vector for Streptococcus thermophilus based on the α-complementation of β-galactosidase

Streptococcus thermophilus is a common yogurt starter that consumes lactose as its primary carbon source. The enzyme β-galactosidase is essential for the lactose metabolism and the growth of this species. Streptococcus thermophilus appears to be a promising cell factory. Food-grade vectors have advantages in heterologous protein expression. This study aimed to determine whether the β-galactosidase of S. thermophilus has the α-complementary characteristic and to develop a novel food-grade vector based on this phenomenon. The N-terminal 7 to 36 AA residues of the β-galactosidase in S. thermophilus were deleted. The obtained mutant S. thermophilus Δα lost β-galactosidase activity and growth ability in the lactose medium. Subsequently, plasmids expressing α-fragments with different lengths of 1 to 36 (Sα1), 1 to 53 (Sα2), and 1 to 88 (Sα3) AA were constructed and transformed into S. thermophilus Δα. Recombinant S. thermophilus Δα expressing Sα2 or Sα3 recovered the ability to grow in the lactose medium, and their β-galactosidase activity accounted for 24.5% or 11.5% of the wild strain, respectively. These results indicated that the α-complementation system of β-galactosidase existed in S. thermophilus. Based on the characteristic, a food-grade vector pSEα was constructed. Except for Sα2, vector pSEα expressed the α-donor derived from E. coli β-galactosidase. This facilitated the construction of recombinant plasmids in E. coli DH5α and thus improved the transformation efficiency of S. thermophilus. Green fluorescent protein as a reporter protein could be highly expressed in S. thermophilus using this vector. As a result, pSEα is an efficient and safe vector for S. thermophilus with potential food applications.

Longitudinal Cognitive Decline in Patients With Mild Cognitive Impairment or Dementia Due to Alzheimer's Disease

Sensitive cognitive assessments accurately detect and track cognitive decline in Alzheimer's disease. The Cogstate battery was used to measure cognitive change in cognitively normal participants and in individuals with mild cognitive impairment and mild Alzheimer's disease enrolled in the Australian Imaging, Biomarker and Lifestyle Rate of Change Substudy. Over 18 months, verbal episodic memory performance declined for mild cognitive impairment and mild Alzeheimer's disease groups when compared to cognitively normal participants. Frequent assessments of episodic memory may facilitate early detection of cognitive decline due to Alzheimer's disease.

Layer-by-Layer Cell Encapsulation for Drug Delivery: The History, Technique Basis, and Applications

The encapsulation of cells with various polyelectrolytes through layer-by-layer (LbL) has become a popular strategy in cellular function engineering. The technique sprang up in 1990s and obtained tremendous advances in multi-functionalized encapsulation of cells in recent years. This review comprehensively summarized the basis and applications in drug delivery by means of LbL cell encapsulation. To begin with, the concept and brief history of LbL and LbL cell encapsulation were introduced. Next, diverse types of materials, including naturally extracted and chemically synthesized, were exhibited, followed by a complicated basis of LbL assembly, such as interactions within multilayers, charge distribution, and films morphology. Furthermore, the review focused on the protective effects against adverse factors, and bioactive payloads incorporation could be realized via LbL cell encapsulation. Additionally, the payload delivery from cell encapsulation system could be adjusted by environment, redox, biological processes, and functional linkers to release payloads in controlled manners. In short, drug delivery via LbL cell encapsulation, which takes advantage of both cell grafts and drug activities, will be of great importance in basic research of cell science and biotherapy for various diseases.

Site-directed mutation of β-galactosidase from Streptococcus thermophilus for galactooligosaccharide-enriched yogurt making

β-Galactosidase is one of the most important enzymes used in dairy processing. It converts lactose into glucose and galactose, and also catalyzes galactose to form galactooligosaccharides (GOS), so-called prebiotics. However, most of the β-galactosidases from the starter cultures have low transgalactosylation activities, the process that results in galactose accumulation in yogurt. Here, a site-directed mutation strategy was attempted, to genetically modify β-galactosidase from Streptococcus thermophilus. Out of 28 Strep. thermophilus strains, a β-galactosidase gene named bgaQ, encoded for high β-galactosidase hydrolysis activity (BgaQ), was cloned from the strain Strep. thermophilus SDMCC050237. It was 3,081 bp in size, with 1,027 deduced amino acid residuals, which belonged to the GH2 family. After replacing the Tyr⁸⁰¹ and Pro⁸⁰² around the active sites of BgaQ with His⁸⁰¹ and Gly⁸⁰², the GOS synthesis of the generated mutant protein BgaQ-8012 increased from 20.5% to 26.7% at 5% lactose, and no hydrolysis activity altered obviously. Subsequently, the purified BgaQ or BgaQ-8012 was added to sterilized milk inoculated with 2 starters from Strep. thermophilus SDMCC050237 and Lactobacillus delbrueckii ssp. bulgaricus ATCC11842. The GOS yields with added BgaQ or BgaQ-8012 rose to 5.8 and 8.3 g/L, respectively, compared with a yield of 3.7 g/L without enzymes added. Meanwhile, the addition of the BgaQ or BgaQ-8012 reduced the lactose content by 49.3% and 54.4% in the fermented yogurt and shortened the curd time. Therefore, this study provided a site-directed mutation strategy for improvement of the transgalactosylation activity of β-galactosidase from Strep. thermophilus for GOS-enriched yogurt making.

Squeezed-Light Enhancement and Backaction Evasion in a High Sensitivity Optically Pumped Magnetometer

We study the effect of optical polarization squeezing on the performance of a sensitive, quantum-noise-limited optically pumped magnetometer. We use Bell-Bloom (BB) optical pumping to excite a ^{87}Rb vapor containing 8.2×10^{12}  atoms/cm^{3} and Faraday rotation to detect spin precession. The sub-pT/sqrt[Hz] sensitivity is limited by spin projection noise (photon shot noise) at low (high) frequencies. Probe polarization squeezing both improves high-frequency sensitivity and increases measurement bandwidth, with no loss of sensitivity at any frequency, a direct demonstration of the evasion of measurement backaction noise. We provide a model for the quantum noise dynamics of the BB magnetometer, including spin projection noise, probe polarization noise, and measurement backaction effects. The theory shows how polarization squeezing reduces optical noise, while measurement backaction due to the accompanying ellipticity antisqueezing is shunted into the unmeasured spin component. The method is compatible with high-density and multipass techniques that reach extreme sensitivity.

[BK virus encephalitis in children with hematopoietic stem cell transplantation]

目的

探讨异基因造血干细胞移植患儿中BK病毒（BKV）脑炎的发病率、病死率、中位发病时间、临床表现、诊治及转归等，以提高临床医师对本病的认识。

方法

回顾性分析2015年1月1日至2020年12月31日在北京大学人民医院接受单倍型造血干细胞移植治疗的709例儿童患者，其中14例诊断为BKV脑炎，分析其临床特征、治疗过程及转归。

结果

BKV脑炎发生率为1.97％（14例）。患儿多为男性（12例），中位年龄为11岁，中位发病时间为移植后第55天。最常见的临床表现为意识障碍、抽搐发作（7例）。14例患儿予阿昔洛韦、更昔洛韦单用，或联合丙种球蛋白治疗，9例患儿痊愈，1例患儿死于病毒性脑炎，4例患儿死于其他疾病，病死率为35.7％。

结论

BKV脑炎主要表现为脑炎或脑膜炎。虽然确诊BKV脑炎后积极予药物治疗，但许多患者仍死于多器官衰竭或其他并发症。当异基因造血干细胞移植患者出现神经系统症状、出血性膀胱炎时，必须高度警惕BKV脑炎，尽早施救，从而改善患者的生存率及生活质量。

Computational Drug Repurposing for Alzheimer's Disease Using Risk Genes From GWAS and Single-Cell RNA Sequencing Studies

Background: Traditional therapeutics targeting Alzheimer's disease (AD)-related subpathologies have so far proved ineffective. Drug repurposing, a more effective strategy that aims to find new indications for existing drugs against other diseases, offers benefits in AD drug development. In this study, we aim to identify potential anti-AD agents through enrichment analysis of drug-induced transcriptional profiles of pathways based on AD-associated risk genes identified from genome-wide association analyses (GWAS) and single-cell transcriptomic studies. Methods: We systematically constructed four gene lists (972 risk genes) from GWAS and single-cell transcriptomic studies and performed functional and genes overlap analyses in Enrichr tool. We then used a comprehensive drug repurposing tool Gene2Drug by combining drug-induced transcriptional responses with the associated pathways to compute candidate drugs from each gene list. Prioritized potential candidates (eight drugs) were further assessed with literature review. Results: The genomic-based gene lists contain late-onset AD associated genes (BIN1, ABCA7, APOE, CLU, and PICALM) and clinical AD drug targets (TREM2, CD33, CHRNA2, PRSS8, ACE, TKT, APP, and GABRA1). Our analysis identified eight AD candidate drugs (ellipticine, alsterpaullone, tomelukast, ginkgolide A, chrysin, ouabain, sulindac sulfide and lorglumide), four of which (alsterpaullone, ginkgolide A, chrysin and ouabain) have shown repurposing potential for AD validated by their preclinical evidence and moderate toxicity profiles from literature. These support the value of pathway-based prioritization based on the disease risk genes from GWAS and scRNA-seq data analysis. Conclusion: Our analysis strategy identified some potential drug candidates for AD. Although the drugs still need further experimental validation, the approach may be applied to repurpose drugs for other neurological disorders using their genomic information identified from large-scale genomic studies.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

Transanal mesorectal excision: early outcomes in Australia and New Zealand

BACKGROUND

Transanal total mesorectal excision (taTME) aims to overcome some of the technical challenges faced when operating on mid and low rectal cancers. Specimen quality has been confirmed previously, but recent concerns have been raised about oncological safety. This multicentre prospective study aimed to evaluate the safety of taTME among early adopters in Australia and New Zealand.

METHODS

Data from all consecutive patients who had taTME for rectal cancer from July 2014 to February 2020 at six tertiary referral centres in Australasia were recorded and analysed.

RESULTS

A total of 308 patients of median age of 64 years underwent taTME. Some 75.6 per cent of patients were men, and the median BMI was 26.8 kg/m2. The median distance of tumour from anal verge was 7 cm. Neoadjuvant chemoradiotherapy was administered to 57.8 per cent of patients. The anastomotic leak rate was 8.1 per cent and there was no mortality within 30 days of surgery. Pathological examination found a complete mesorectum in 295 patients (95.8 per cent), a near-complete mesorectum in seven patients (2.3 per cent), and an incomplete mesorectum in six patients (1.9 per cent). The circumferential resection margin and distal resection margin was involved in nine patients (2.9 per cent), and two patients (0.6 per cent) respectively. Over a median follow-up of 22 months, the local recurrence rate was 1.9 per cent and median time to local recurrence was 30.5 months.

CONCLUSION

This study showed that, with appropriate training and supervision, skilled minimally invasive rectal cancer surgeons can perform taTME with similar pathological and oncological results to open and laparoscopic surgery.

MiR-1301 promotes adipogenic and osteogenic differentiation of BMSCs by targeting Satb2

OBJECTIVE

Bone marrow mesenchymal stem cells (BMSCs) have the ability to differentiate into several cell lines and are critical for skeletal microenvironment and bone development. MiR-1301 is involved in multiple pathological and physiological processes. However, miR-1301's role in BMSCs adipogenic and osteogenic differentiation remains unclear.

MATERIALS AND METHODS

Rat BMSCs were isolated and randomly divided into control group, miR-1301 group, and miR-1301 siRNA group followed by analysis of the expression of miR-1301, Bax, Bcl-2, UNX2, and OPN, as well as FABP4 and PPARγ2 by Real Time-PCR. Cell proliferation was assessed by MTT assay and the relationship between miR-1301 and Satb2 was evaluated by the Dual-Luciferase reporter assay. Satb2 expression was detected by Western blot.

RESULTS

The pcDNA-miR-1301 plasmid was transfected into BMSCs to upregulate the expression of miR-1301, which promoted cell proliferation, decreased Bax expression, and increased Bcl-2 expression and ALP activity. In addition, it also elevated the expression of RUNX2 and OPN and decreased the expression of FABP4, PPARγ2, and Satb2. Compared with the control group, the difference was statistically significant (p<0.05); Satb2 was the target gene of miR-1301. MiR-1301 siRNA transfected into BMSCs down-regulated miR-1301 expression, inhibited cell proliferation, increased Bax expression and decreased Bcl-2 expression and ALP activity. Meanwhile, miR-1301 siRNA also reduced RUNX2 and OPN expression and increased expression of FABP4, PPARγ2 and Satb2. The difference was statistically significant compared with control group (p<0.05).

CONCLUSIONS

Regulation of miR-1301 expression in BMSCs can improve BMSCs proliferation and regulate their adipogenic and osteogenic differentiation by regulating Satb2.

NIX Mediates Mitophagy in Spinal Cord Injury in Rats by Interacting with LC3

Excessive mitophagy plays a role in neuronal death in spinal cord injury (SCI), its molecular regulation remains largely unknown. The present study aims to determine the role of NIX, a member of a unique subfamily of death-inducing mitochondrial proteins, in the regulation of mitophagy in SCI. Here we show that NIX is highly upregulated in SCI and hypoxia, and localized to mitochondria. The mitochondria-bound NIX interacts with autophagosome-localized LC3 (Microtubule-associated protein 1 light chain 3) to form a mitochondria-NIX-LC3-autophagosome complex, resulting in excessive mitophagy in SCI. Downregulation of NIX by RNA interference restores the function of mitochondria in spinal cord neurons under hypoxia. Importantly, inhibition of NIX improves recovery of locomotor function in rats after SCI. The present study demonstrates that NIX interacts with LC3 to activate excessive mitophagy in SCI. Inhibition of NIX is therefore likely a neuroprotective strategy.

Reduced Granule Cell Proliferation and Molecular Dysregulation in the Cerebellum of Lysosomal Acid Phosphatase 2 (ACP2) Mutant Mice

Lysosomal acid phosphatase 2 (Acp2) mutant mice (naked-ataxia, nax) have a severe cerebellar cortex defect with a striking reduction in the number of granule cells. Using a combination of in vivo and in vitro immunohistochemistry, Western blotting, BrdU assays, and RT-qPCR, we show downregulation of MYCN and dysregulation of the SHH signaling pathway in the nax cerebellum. MYCN protein expression is significantly reduced at P10, but not at the peak of proliferation at around P6 when the number of granule cells is strikingly reduced in the nax cerebellum. Despite the significant role of the SHH-MycN pathway in granule cell proliferation, our study suggests that a broader molecular pathway and additional mechanisms regulating granule cell development during the clonal expansion period are impaired in the nax cerebellum. In particular, our results indicate that downregulation of the protein synthesis machinery may contribute to the reduced number of granule cells in the nax cerebellum.

Implication of post-translationally modified SOD1 in pathological aging

Why certain people relish healthy aging throughout their life span while others suffer pathological consequences? In this review, we focus on some of the dominant paradigms of pathological aging, such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), and Parkinson's disease (PD), and predict that the antioxidant superoxide dismutase 1 (SOD1), when post-translationally modified by aging-associated oxidative stress, acts as a mechanism to accelerated aging in these age-related neurodegenerative diseases. Oxidative modifications of natively reduced SOD1 induce pathological confirmations such as misfolding, leading to a subsequent formation of monomeric, oligomeric, and multimeric aggregates. Misfolded SOD1 propagates like prions from cell to cell. These modified conformations are detected in brain tissues in ALS, AD, and PD, and are considered a contributing factor to their initial pathogenesis. We have also elaborated on oxidative stress-induced non-native modifications of SOD1 and offered a logistic argument on their global implication in accelerated or pathological aging in the context of ALS, AD, and PD.

Peptide transporter-related protein 2 plays an important role in glutathione transport of Streptococcus thermophilus

Streptococcus thermophilus is widely used as a starter culture in the fermentation of yogurt. Glutathione (GSH; γ-glutamyl-cysteinyl-glycine), as a tripeptide, has an important physiological role for Strep. thermophilus. However, the scope of the GSH transport proteins is still unexplored in this species. In the present study, 5 peptide transporter-related proteins (Ptrp) of Strep. thermophilus strain ST-1 were selected and then inactivated by gene insertion, respectively. Through detection and comparison of intracellular GSH content of mutant strain and wild strain, we identified 2 proteins, named Ptrp-2 and Ptrp-4, that might be related to GSH transport. Reverse-transcriptase quantitative PCR was performed to verify the gene expressions of these 2 possible GSH transport-related proteins, and it was finally determined that Ptrp-2 plays an important role in GSH transport of Strep. thermophilus. Milk fermentation experiments were further conducted to test the effect of Ptrp-2 on the characteristics of yogurt. The results showed that the fermented milk hardly curds using the mutant strain, indicating that Ptrp-2 is important for Strep. thermophilus as a yogurt starter.

Ketogenic diet protects myelin and axons in diffuse axonal injury

BACKGROUND

Ketogenic diet (KD) has been identified as a potential therapy to enhance recovery after traumatic brain injury (TBI). Diffuse axonal injury (DAI) is a common type of traumatic brain injury that is characterized by delayed axonal disconnection. Previous studies showed that demyelination resulting from oligodendrocyte damage contributes to axonal degeneration in DAI.

AIM

The present study tests a hypothesis that ketone bodies from the ketogenic diet confers protection for myelin and attenuates degeneration of demyelinated axon in DAI.

METHODS

A modified Marmarou's model of DAI was induced in adult rats. The DAI rats were fed with KD and analyzed with western blot, transmission electron microscope, ELISA test and immunohistochemistry. Meanwhile, a co-culture of primary oligodendrocytes and neurons was treated with ketone body β-hydroxybutryate (βHB) to test for its effects on the myelin-axon unit.

RESULTS

Here we report that rats fed with KD showed an increased fatty acid metabolism and ketonemia. This dietary intervention significantly reduced demyelination and attenuated axonal damage in rats following DAI, likely through inhibition of DAI-induced excessive mitochondrial fission and promoting mitochondrial fusion. In an in vitro model of myelination, the ketone body βHB increased myelination significantly and reduced axonal degeneration induced by glucose deprivation (GD). βHB robustly increased cell viability, inhibited GD-induced collapse of mitochondrial membrane potential and attenuated death of oligodendrocytes.

CONCLUSION

Ketone bodies protect myelin-forming oligodendrocytes and reduce axonal damage. Ketogenic diet maybe a promising therapy for DAI.

Prognostic factors influencing survival in patients undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for isolated colorectal peritoneal metastases: a systematic review and meta-analysis

AIM

Peritoneal metastases from colorectal cancer confer the worst survival among all metastatic sites. The adoption of cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) can offer selected patients with isolated colorectal peritoneal metastases (CRPM) a favourable long-term survival. There are numerous factors postulated to influence survival in patients undergoing CRS and HIPEC. The aim of this study was to identify the key perioperative prognostic factors that influence survival in patients undergoing CRS and HIPEC for isolated CRPM.

METHOD

A systematic review and meta-analysis were conducted to evaluate prognostic factors influencing survival in patients undergoing CRS and HIPEC for isolated CRPM.

RESULTS

Thirty-three studies fitted the inclusion criteria for the systematic review, with 25 studies included in the meta-analysis. On pooled analysis, incomplete cytoreduction, increasing peritoneal carcinoma index (PCI) and lymph node involvement were significantly associated with a worse survival. Additionally, a rectal primary [hazard ratio (HR) 1.93, 95% CI 1.10-3.37], adjuvant chemotherapy (HR 0.71, 95% CI 0.54-0.93) and perioperative grade III/IV morbidity (HR 1.59, 95% CI 1.17-2.16) were also found to significantly influence survival. Notably, tumour differentiation and signet ring cell histology did not influence survival on pooled analysis.

CONCLUSION

This meta-analysis confirms that in patients undergoing CRS and HIPEC for isolated CRPM, incomplete cytoreduction, high PCI and lymph node involvement have a negative influence on survival. In addition, a rectal primary, adjuvant chemotherapy use and grade III/IV morbidity are important factors that also significantly influence survival.

Compromised Lactate Efflux Renders Vulnerability of Oligodendrocyte Precursor Cells to Metabolic Stresses

Among the brain cells, oligodendrocyte progenitor cells (OPCs) are the most vulnerable in response to hypoxic and ischemic insults, of which the mechanism remains unknown. Brain cells are known to import or export lactate via differentially expressed monocarboxylate transporters (MCTs) to maintain energy metabolism and pH homeostasis. The present study aims to determine the role of MCT1 in the high vulnerability of OPCs. Here we show that a mild ischemic condition equivalent to ischemic preconditioning caused detectable loss of OPCs. MCT1, which is primarily expressed in oligodendrocyte lineage cells including OPCs, was up-regulated immediately under oxygen-glucose deprivation (OGD) conditions. However, persistent hypoxia, but not hypoglycemia, inhibited the function of MCT1, leading to an intracellular lactate accumulation and acidosis in OPCs. Neurons, which express primarily MCT2, were able to export lactate and maintain an intracellular pH homeostasis under similar conditions. The results support that compromised lactate efflux resulting from hypoxia-induced dysfunction of MCT1 contributes to the high vulnerability of OPCs.

Alteration of the Dopamine Receptors' Expression in the Cerebellum of the Lysosomal Acid Phosphatase 2 Mutant (Naked-Ataxia (NAX)) Mouse

A spontaneous mutation in the lysosomal acid phosphatase (Acp2) enzyme (nax: naked-ataxia) in experimental mice results in delayed hair appearance and severe cytoarchitectural impairments of the cerebellum, such as a Purkinje cell (PC) migration defect. In our previous investigation, our team showed that Acp2 expression plans a significant role in cerebellar development. On the other hand, the dopaminergic system is also a player in central nervous system (CNS) development, including cerebellar structure and function. In the current investigation, we have explored how Acp2 can be involved in the regulation of the dopaminergic pathway in the cerebellum via the regulation of dopamine receptor expression and patterning. We provided evidence about the distribution of different dopamine receptors in the developing cerebellum by comparing the expression of dopamine receptors on postnatal days (P) 5 and 17 between nax mice and wild-type (wt) littermates. To this aim, immunohistochemistry and Western blot analysis were conducted using five antibodies against dopamine receptors (DRD1, -2, -3, -4, and -5) accompanied by RNAseq data. Our results revealed that DRD1, -3, and -4 gene expressions significantly increased in nax cerebella but not in wt, while gene expressions of all 5 receptors were evident in PCs of both wt and nax cerebella. DRD3 was strongly expressed in the PCs' somata and cerebellar nuclei neurons at P17 in nax mice, which was comparable to the expression levels in the cerebella of wt littermates. In addition, DRD3 was expressed in scattered cells in a granular layer reminiscent of Golgi cells and was observed in the wt cerebella but not in nax mice. DRD4 was expressed in a subset of PCs and appeared to align with the unique parasagittal stripes pattern. This study contributes to our understanding of alterations in the expression pattern of DRDs in the cerebellum of nax mice in comparison to their wt littermates, and it highlights the role of Acp2 in regulating the dopaminergic system.

Necrostatin-1 prevents the proapoptotic protein Bcl-2/adenovirus E1B 19-kDa interacting protein 3 from integration into mitochondria

Necrostatin-1 (Nec-1) has previously been shown to protect neurons from death in traumatic and ischemic brain injuries. This study tests the hypothesis that Nec-1 protects neural cells against traumatic and ischemic brain injuries through inhibition of the Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNIP3). We have used biochemical and morphological techniques to determine the inhibition of Nec-1 on BNIP3-induced cell death and to identify its mechanism of action in in vivo and in vitro models of neurodegeneration. Here we show that Nec-1 significantly increased neuronal viability following prolonged exposure to hypoxia in vitro, and attenuated myelin damage and neuronal death in traumatic brain injury and cerebral ischemia in Sprague-Dawley rats. Nec-1 alleviated traumatic brain injury-induced up-regulation of BNIP3 in mature oligodendrocytes. In isolated mitochondria, Nec-1 prevented BNIP3 from integrating into mitochondria by modifying its binding sites on the mitochondria. Consequently, Nec-1 robustly inhibited BNIP3-induced collapse of mitochondrial membrane potential and reduced the opening probability of mitochondrial permeability transition pores. Nec-1 also preserved mitochondrial ultrastructure and suppressed BNIP3-induced nuclear translocation of apoptosis-inducing factor. In conclusion, Nec-1 protects neurons and oligodendrocytes against traumatic and ischemic brain injuries by targeting the BNIP3-induced cell death pathway, and is a novel inhibitor for BNIP3. Cover Image for this issue: https://doi.org/10.1111/jnc.15056.

Selective Susceptibility of Oligodendrocytes to Carbon Monoxide Poisoning: Implication for Delayed Neurologic Sequelae (DNS)

Delayed neurologic sequelae (DNS) are recurrent-transient neuropsychiatric consequences of carbon monoxide (CO) intoxication. Pathologically DNS features damages to the brain white matter. Here we test a hypothesis that direct cytotoxicity of CO to oligodendrocytes plays a role in the development of DNS. In an in vitro model of CO poisoning with the carbon monoxide releasing molecule-2 (CORM-2) as a CO donor, we show that CORM-2 at concentrations higher than 200 µM significantly inhibited viability and caused significant death of PC12 cells. Similar minimum toxicity concentration was observed on primary brain cells including neurons, astrocytes, and microglia. Interestingly, oligodendrocytes showed cytotoxicity to CORM-2 at a much lower concentration (100 µM). We further found that CORM-2 at 100 µM inhibited proteolipid protein (PLP) production and reduced myelin coverage on axons in an in vitro model of myelination. Our results show that direct cytotoxicity is a mechanism of CO poisoning and DNS may result from a high susceptibility of oligodendrocytes to CO poisoning.

The Long-Term Effects of Adolescent Social Defeat Stress on Oligodendrocyte Lineage Cells and Neuroinflammatory Mediators in Mice

OBJECTIVE

Adverse childhood and adolescent experiences are associated with the emergences of psychopathology later in life and have negative consequences on white matter integrity. However, this adversity-induced white matter impairment remains not fully investigated.

METHODS

Adolescent Balb/c mice were subjected to intermittent social defeat stress once a day during postnatal days 25 to 40. Then, the subjects were allowed to recover for three weeks before sacrifice. At the end, oligodendrocyte (OL) lineage cells, cell proliferation, and microglia activation, as well as myelin basic protein (MBP) levels in frontal cortex and hippocampus were evaluated. The levels of interleukin (IL)-1β and IL-6 in the brain regions were assessed.

RESULTS

MBP protein level in frontal cortex, but not in the hippocampus of defeated mice, decreased significantly compared to controls. The numeral densities of mature OLs, oligodendrocyte progenitor cells, and proliferating cells in medial prefrontal cortex were comparable between the defeated mice and controls. The defeated mice, however, showed significantly higher IL-1β level, although IL-6 level and numeral density of microglia in frontal cortex did not change relative to controls.

CONCLUSION

These results indicate that effects of intermittent social defeat stress on the white matter integrity and OL lineage cells in mouse brain are region- and developmental stage-specific. Upregulated IL-1β may contribute to this negative consequence though the underlying mechanism remains to be investigated.

Primary Culture of Neurons Isolated from Embryonic Mouse Cerebellum

The use of primary cell cultures has become one of the major tools to study the nervous system in vitro. The ultimate goal of using this simplified model system is to provide a controlled microenvironment and maintain the high survival rate and the natural features of dissociated neuronal and nonneuronal cells as much as possible under in vitro conditions. In this article, we demonstrate a method of isolating primary neurons from the developing mouse cerebellum, placing them in an in vitro environment, establishing their growth, and monitoring their viability and differentiation for several weeks. This method is applicable to embryonic neurons dissociated from cerebellum between embryonic days 12-18.

Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 ¹/₂ years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

Atractylenolide III ameliorates cerebral ischemic injury and neuroinflammation associated with inhibiting JAK2/STAT3/Drp1-dependent mitochondrial fission in microglia

BACKGROUND

Inflammation is a major contributor to stroke pathology, making it a promising strategy for intervention. Microglia, the resident macrophages in the brain, play essential roles in both the generation and resolution of neuroinflammation. In particular, mitochondrial homeostasis is critical for microglial function and its dysregulation is involved in the pathogenesis of ischemic stroke. Atractylenolide III (A III), a sesquiterpene lactone found in Atractylodes macrocephala Koidz, has been shown to have an inhibitory effect on inflammation. However, its effect specifically on neuroinflammation and microglial mitochondrial homeostasis following stroke remains elusive.

HYPOTHESIS

We hypothesized that A III protects against brain ischemia through inhibition of neuroinflammation mediated by JAK2/STAT3/Drp1-dependent mitochondrial fission.

METHODS

The neuroprotective and anti-neuroinflammatory effects of A III were investigated in vivo in mice with transient occlusion to the middle cerebral artery (MCAO) and in vitro in oxygen glucose deprivation-reoxygenation (OGDR)-stimulated primary microglia from mice.

RESULTS

A III and AG490, an inhibitor of JAK2, treatment reduced brain infarct size, restored cerebral blood flow (CBF), ameliorated brain edema and improved neurological deficits in MCAO mice. Furthermore, A III and AG490 inhibited mRNA and protein expressions of proinflammatory (IL-1β, TNF-α, and IL-6) and anti-inflammatory cytokines in both MCAO mice and OGDR-stimulated primary microglia. The JAK2/STAT3 pathway was effectively suppressed by A III, similar to the effect of AG490 treatment. In addition, A III and AG490 treatments significantly decreased Drp1 phosphorylation, translocation and mitochondrial fission in primary microglia stimulated with OGDR for 24 h.

CONCLUSION

Our study demonstrated that A III was able to reduce complications associated with ischemia through inhibiting neuroinflammation, which was mediated in part by JAK2/STAT3-dependent mitochondrial fission in microglia.

Myelin Damage in Diffuse Axonal Injury

Diffuse axonal injury (DAI) is characterized by delayed axonal disconnection. Although the effect of DAI on axonal pathology has been well documented, there is limited information regarding the role of myelin in the pathogenesis of DAI. We used a modified Marmarou method to create a moderate DAI model in adult rat and examined the corpus callosum and brain stem for myelin pathology and dynamic glial responses to DAI. During the first week following DAI, Luxol Fast Blue staining and western blot analysis for MBP showed significant loss of myelin in the corpus callosum and the brain stem. Increased apoptosis of mature oligodendrocyte, as depicted by its marker CC-1, was observed. Conversely, there was an increased number of Olig2-positive cells accompanied by hypertrophic microglia/macrophage and mild reactive astrocytes. Electron microscopy revealed degenerating axons in the corpus callosum and marked myelin abnormalities in the brain stem in the early stage of DAI. Brain stem regions exhibited myelin intrusions or external protrusions with widespread delamination and myelin collapse, leading to degeneration of accompanying axons. Our results show distinct pathologic processes involving axon and myelin between the corpus callosum and the brain stem in DAI. Oligodendrocyte selective vulnerability and subsequent demyelination may contribute to axonal degeneration in the brain stem. Defining the cause of ongoing oligodendrocyte death and promoting myelin regeneration may provide important targets for therapeutic interventions of DAI.

[Clinical analysis of hemorrhagic cystitis in children and adolescents with hematological diseases post haplo-hematopoietic stem cell transplantation]

目的

观察儿童及青少年血液病患者单倍型造血干细胞移植（haplo-HSCT）后出血性膀胱炎（HC）的临床特征并探讨其影响因素。

方法

回顾性分析2015至2016年接受haplo-HSCT的89例儿童及青少年血液病患者的临床资料。

结果

全部89例患者中，≤14岁62例（儿童组）、>14~<18岁27例（青少年组）；男56例，女33例；中位移植年龄10（1~17）岁；急性淋巴细胞白血病（ALL）44例，急性髓系白血病（AML）33例，急性混合细胞白血病（AHL）3例，骨髓增生异常综合征（MDS）9例。移植物来源均为骨髓+外周血干细胞。全部89例患者中32例（36%）发生HC，其中迟发型31例，早发型1例；Ⅰ度6例、Ⅱ度16例、Ⅲ度8例、Ⅳ度2例；HC发病中位时间为移植后25（2~55）d，中位持续时间为19（3~95）d；所有患儿均获得治愈。儿童组HC发病率低于青少年组[27.4%（17/62）对55.6%（15/27），χ²=6.466，P<0.05]。儿童组中<5岁组HC发生率低于5~14岁组[0（0/12）对34%（17/50），χ²=4.043，P<0.05]。

结论

HC是儿童及青少年血液病患者haplo-HSCT的常见并发症，总体预后良好，年龄是其发生的影响因素。