High-level dialogue deliberated solutions for gender equality and climate resilience in Africa

Climate change harms women disproportionately, exposing social and gender inequalities across the globe. At the same time, women are essential for transforming food systems that increase resilience, food and nutrition security and well-being for entire communities. That was the key message delivered at the 1st high-level dialogue on gender and climate change in Africa at the International Livestock Research Institute (ILRI) in Nairobi, Kenya, on 12 October 2022, convened by CGIAR’s Gender Equality (HER+) initiative, designed to address gender challenges in Global South food systems affected by climate change

Distant chaperones and N-glycan signals : new mechanisms of secretory pathway proteostasis

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 2018.Page 176 blank. Cataloged from PDF version of thesis.Includes bibliographical references.Approximately one-third of all cellular proteins traverse the secretory pathway. After translation and folding in the endoplasmic reticulum (ER), proteins are transported through the Golgi to their final locations inside or outside of cells. At each step, proteins are helped by chaperones, which both shepherd proteins towards their native structures and serve as gatekeepers for export. Many proteins in the secretory pathway are also modified by installation of polysaccharides on specific asparagine residues. These N-glycans are installed in the ER as uniform precursors, but are trimmed and built up by Golgi glycan maturation enzymes into a striking array of epitopes. N-glycans act as a second mechanism to stabilize protein structure and prevent the release of misfolded proteins. Outside the cell, N-glycans on cell surfaces and secreted, soluble proteins allow cells to interact with each other, with their environment, and with distal tissues. During development, cells encounter physiological ER stress incurred by high levels of sustained protein production. Unresolved protein misfolding, on the other hand, results in pathological ER stress and tissue dysfunction. Prior work has used small model substrates to show that cells utilize secretory pathway chaperones and tune N-glycosylation to respond to ER stress. This thesis examines how cells use similar strategies to accommodate challenging cargoes such as collagen-1. In the human body, collagen-I constitutes the primary protein component of bone, skin, and other organs; collagen-I misfolding results in pathological ER stress and connective tissue diseases. We therefore set out 1) to identify cellular components required for collagen-I secretion that could be targeted to address disease and 2) to assess the effects of ER stress on both cellular N-glycan structures and individual glycoproteins. Here, we employ a high-throughput assay for collagen-I secretion and find that the cytosolic isoform of Hsp90 is required for collagen-I export. We also show that intracellular stress signaling alters the structures of cell surface and secreted N-glycans. Finally, we demonstrate that the collagen-I N-glycan buffers collagen-I folding against destabilizing mutations and ER stress. Our results identify potential therapeutic leads for collagen misfolding diseases and point to new mechanisms for maintaining secretory pathway proteostasis.by Madeline Y. Wong.Ph. D

Improving Senior Fitness Programs & Dementia Care (Canadian Centre for Activity & Aging)

Our team worked alongside the Canadian Centre for Activity and Aging (CCAA) to improve senior fitness programs and dementia care through volunteering at weekly exercise classes, assisting with fitness assessments, and creating two tangible deliverables. Our first deliverable was a Wordle; a tool for visualizing the modifiable risk factors of dementia. By consulting existing literature, we concluded that hearing loss, low education status, depression, and smoking were the main modifiable risk factors. This Wordle will be used for future research and educational purposes. Our next deliverables targeted the fitness aspect of the CCAA. We helped facilitate weekly instructor-led fitness classes and recorded our observations each time. We also conducted a functional fitness assessment to obtain baseline measurements of each participant’s functional abilities. Future measurements can then be compared with these values to evaluate the fitness classes’ efficacy at reducing or ameliorating declines in physical functioning. Some assessments required more time to complete than others, which reduced testing efficiency. Participants had the most difficulty with the timed up-and-go, 30-second arm curl, 30-second chair stand, and 2-minute step tests. Male participants were less likely to meet established standards compared with their female counterparts. Measurements were recorded using the Healthy Active Living Database (HAroLD) which was straightforward but difficult to use in real-time. Observations and recommendations were summarized with an infographic that will inform the CCAA’s management team about our contributions this term. Future students working with the CCAA can use our deliverables to improve the curriculum

Effects of vitamin D3 and its chemical analogs on the growth of Hodgkin’s lymphoma, in vitro

Objective: Vitamin D receptor (VDR) activities have been noted for a number of B cell malignancies which showed varying sensitivities to vitamin D3 (1,25-dihydroxyvitamin D3, VD3, calcitriol) and its synthetic analogs. The objective of this study was to address the potential effects of VD3 and vitamin D3 analogs (VDAs) on the growth of Hodgkin’s lymphoma (HL), a malignant pathology of B cell origin, in vitro. Results: Immunofluorescence staining showed the expression of VDR by primary Hodgkin’s (H) and Reed–Sternberg (RS)—HRS-tumor cells in HL histological sections. Western blot analyses revealed expression of VDR in the HL cell lines Hs445, HDLM2, KMH2, and L428. One-way analysis of variance (ANOVA) on data obtained from water-soluble tetrazolium 1 (WST-1) cell proliferation assay showed decreased cell growth in HDLM2 and L428, 72 h after treatment with 10 μM of either VD3 of VDAs. Western blot analyses showed that treatment of L428 cells with the VDAs (calcipotriol and EB1089) resulted in modest increases in nuclear accumulation of VDR (nuVDR) compared to either dimethyl sulfoxide (DMSO) or VD3 treatments. nuVDR for DMSO control and VD3 was comparable. These results suggest that VD3 or VDAs may affect growth of HL

Loss of H2A.Z Is Not Sufficient to Determine Transcriptional Activity of Snf2-Related CBP Activator Protein or p400 Complexes

The p400 and SRCAP (Snf2-related CBP activator protein) complexes remodel chromatin by catalyzing deposition of histone H2A.Z into nucleosomes. This remodeling activity has been proposed as a basis for regulation of transcription by these complexes. Transcript levels of p21 or Sp1 mRNAs after knockdown of p400 or SRCAP reveals that each regulates transcription of these promoters differently. In this study, we asked whether deposition of H2A.Z within specific nucleosomes by p400 or SRCAP dictates transcriptional activity. Our data indicates that nucleosome density at specific p21 or Sp1 promoter positions is not altered by the loss of either remodeling complex. However, knockdown of SRCAP or p400 reduces deposition of H2A.Z∼50% into all p21 and Sp1 promoter nucleosomes. Thus, H2A.Z deposition is not targeted to specific nucleosomes. These results indicate that the deposition of H2A.Z by the p400 or SRCAP complexes is not sufficient to determine how each regulates transcription. This conclusion is further supported by studies that demonstrate a SRCAPΔATP mutant unable to deposit H2A.Z has similar transcriptional activity as wild-type SRCAP

Recertification guidelines for Massachusetts educators

The incorporation of the extracellular matrix (ECM) is essential for generating in vitro models that truly represent the microarchitecture found in human tissues. However, the cell-cell and cell-ECM interactions in vitro remains poorly understood in placental trophoblast biology. We investigated the effects of varying the surface properties (surface thickness and stiffness) of two ECMs, collagen I and Matrigel, on placental trophoblast cell morphology, viability, proliferation, and expression of markers involved in differentiation/syncytial fusion. Most notably, thicker Matrigel surfaces were found to induce the self-assembly of trophoblast cells into 3D spheroids that exhibited thickness-dependent changes in viability, proliferation, syncytial fusion, and gene expression profiles compared to two-dimensional cultures. Changes in F-actin organization, cell spread morphologies, and integrin and matrix metalloproteinase gene expression profiles, further reveal that the response to surface thickness may be mediated in part through cellular stiffness-sensing mechanisms. Our derivation of self-assembling trophoblast spheroid cultures through regulation of ECM surface alone contributes to a deeper understanding of cell-ECM interactions, and may be important for the advancement of in vitro platforms for research or diagnostics

POLYDOPAMINE AS A BIOMATERIAL FOR HYDROGELS

Hydrogels are networked polymers with hydrophilicity that helps them to retain an ample amount of water. Recent research on hydrogels have been focusing on their use as tissue scaffolding, wound dressings, and drug delivery agents. Polydopamine is formed from the oxidation of dopamine and is attractive as a biomaterial because of the adhesive properties it imparts due to the catechol motif. We proposed polydopamine may behave utility as an antioxidant, as its precursor dopamine has antioxidant properties. We recently developed a method of preparing polysaccharide-polyamine hybrid hydrogels by first reacting the less reactive polysaccharides with the cross-linker epichlorohydrin and completed by the addition of polyamines. Here in we have expanded this methodology to utilize polydopamine as the polyamine. We successfully prepared hydrogels with 10:1, 4:1 and 2:1 dextran:dopamine mass ratios. Using electrostatic crosslinks we also prepared hydrogels from dextran sulfate and polyethyleneimine (PEI) modified with polydopamine, synthesizing 1:1 and a 2:1 PEI:dextran mass ratio hydrogels