Aging
Abstract
Managing immune-related adverse events (irAEs) caused by cancer immunotherapy is essential for developing effective and safer therapies. However, cellular mechanism(s) underlying organ toxicity during anti-PD-(L)1 therapy remain unclear. Here, we investigated the effect of chronological aging on anti-PD-(L)1 therapy-induced irAE-like lung toxicity, utilizing tumor-bearing aged mice. Anti-PD-(L)1 therapy facilitated ectopic infiltration of T and B cells, and antibody deposition in lung of aged but not young mice. Adoptive transfer of aged lung-derived CD4 T cells into TCR-deficient mice revealed that both pathogenic CD4 T cells and aged host environment were necessary for the irAE-inducible responses. Single-cell transcriptomics of lung-infiltrating cells in aged mice demonstrated that anti-PD-(L)1 therapy elicited ICOS+CD4 T-cell activation. Disruption of ICOS-ICOSL interaction attenuated germinal center B-cell differentiation and subsequent lung damage, which were overcome by local administration of IL-21 in the lung of anti-PD-1 therapy-treated aged mice. Therefore, ICOS+CD4 T cells elicited under aged environment exacerbated aberrant immune responses and the subsequent lung dysfunction. Consistent with the findings from mouse model, ICOS up-regulation in CD4 T cells was associated with later irAE incidence in patients with cancer. These finding will help development of useful strategies for irAE management in cancer patients, many of whom are elderly.
Authors
Mari Yokoi, Kosaku Murakami, Tomonori Yaguchi, Kenji Chamoto, Hiroaki Ozasa, Hironori Yoshida, Mirei Shirakashi, Katsuhiro Ito, Yoshihiro Komohara, Yukio Fujiwara, Hiromu Yano, Tatsuya Ogimoto, Daiki Hira, Tomohiro Terada, Toyohiro Hirai, Hirotake Tsukamoto
Abstract
Adult stem cells decline in number and function in old age and identifying factors that can delay or revert age-associated adult stem cell dysfunction are vital for maintaining healthy lifespan. Here we show that Vitamin A, a micronutrient that is derived from diet and metabolized into retinoic acid, acts as an antioxidant and transcriptional regulator in muscle stem cells. We first show that obstruction of dietary Vitamin A in young animals drives mitochondrial and cell cycle dysfunction in muscle stem cells that mimics old age. Next, we pharmacologically targeted retinoic acid signaling in myoblasts and aged muscle stem cells ex vivo and in vivo and observed reductions in oxidative damage, enhanced mitochondrial function, and improved maintenance of quiescence through fatty acid oxidation. We next detected the receptor for vitamin A derived retinol, stimulated by retinoic acid 6 or Stra6, was diminished with muscle stem cell activation and in old age. To understand the relevance of Stra6 loss, we knocked down Stra6 and observed an accumulation of mitochondrial reactive oxygen species, as well as changes in mitochondrial morphology and respiration. These results demonstrate that Vitamin A regulates mitochondria and metabolism in muscle stem cells and highlight a unique mechanism connecting stem cell function with vitamin intake.
Authors
Paula M. Fraczek, Pamela Duran, Benjamin A. Yang, Valeria Ferre, Leanne Alawieh, Jesus A. Castor-Macias, Vivian T. Wong, Steve D. Guzman, Celeste Piotto, Klimentini Itsani, Jacqueline A Larouche, Carlos A. Aguilar
Abstract
Humoral immunity is orchestrated by follicular helper T (Tfh) cells, which promote cognate B cells to produce high-affinity, protective antibodies. In aged individuals, humoral immunity after vaccination is diminished despite the presence of Tfh cells, suggesting defects after initial Tfh formation. In this study, we utilized both murine and human systems to investigate how aging alters Tfh cell differentiation after influenza vaccination. We found that young Tfh cells underwent progressive differentiation after influenza vaccination, culminating in clonal expansion of effector-like cells in both draining lymph nodes and blood. In aging, early stages of Tfh development occurred normally. However, aging rewired the later stages of development in Tfh cells, resulting in a transcriptional program reflective of cellular senescence, sustained pro-inflammatory cytokine production, and metabolic reprogramming. We investigated the extent to which this rewiring of aged Tfh cells is due to the age-associated inflammatory (“inflammaging”) microenvironment and found that this setting was sufficient to both block the transition of Tfh cells to a post-effector resting state and to skew Tfh cells towards the age-rewired state. Together, these data suggest that aging dampens humoral immunity by cytokine-mediated rewiring of late effector Tfh cell differentiation into an activated, yet less functional, cellular state.
Authors
Cody S. Nelson, Manuel A. Podestà, Maya G. Gempler, Jeong-Mi Lee, Cole J. Batty, Peterson G. Mathenge, Asra Sainju, Matthew R. Chang, Hanzhong Ke, Pragya Chandrakar, Elsa Bechu, Sierra Richardson, Cecilia B. Cavazzoni, Stefan G. Tullius, Reza Abdi, Musie Ghebremichael, Marcia C. Haigis, Wayne A. Marasco, Peter T. Sage
Abstract
Acute respiratory distress syndrome (ARDS) results in significant morbidity and mortality, especially in the elderly. Mechanical ventilation, a common supportive treatment for ARDS, is necessary for maintaining gas exchange, but can also propagate injury. We hypothesized that aging leads to alterations in surfactant function, inflammatory signaling, and microvascular permeability within the lung during mechanical ventilation. Young and aged male mice were mechanically ventilated, and surfactant function, inflammation, and vascular permeability were assessed. Additionally, single-cell RNA sequencing was used to delineate cell-specific transcriptional changes. The results showed that in aged mice, surfactant dysfunction and vascular permeability were significantly augmented, while inflammation was less pronounced. Differential gene expression and pathway analyses revealed that alveolar macrophages in aged mice showed a blunted inflammatory response, while aged endothelial cells exhibited altered cell-cell junction formation. In vitro functional analysis revealed that aged endothelial cells had an impaired ability to form a barrier. These results highlight the complex interplay between aging and mechanical ventilation, including an age-related predisposition to endothelial barrier dysfunction, due to altered cell-cell junction formation, and decreased inflammation, potentially due to immune exhaustion. It is concluded that age-related vascular changes may underlie the increased susceptibility to injury during mechanical ventilation in elderly patients.
Authors
Aminmohamed Manji, Lefeng Wang, Cynthia M. Pape, Lynda A. McCaig, Alexandra Troitskaya, Onon Batnyam, Leah J.J. McDonald, C. Thomas Appleton, Ruud A.W. Veldhuizen, Sean E. Gill
Abstract
The mechanisms utilized by differentiating B cells to withstand highly damaging conditions generated during severe infections, like the massive hemolysis that accompanies malaria, are poorly understood. Here we demonstrate that ROCK1 regulates B cells differentiation in hostile environments replete with PAMPs (pathogen-associated molecular patterns) and high levels of heme by controlling two key heme-regulated molecules, BACH2 and Heme-regulated eIF2a kinase (HRI). ROCK1 phosphorylates BACH2 and protects it from heme-driven degradation. As B cells differentiate, furthermore, ROCK1 restrains their proinflammatory potential and helps them handle the heightened stress imparted by the presence of PAMPs and heme by controlling HRI, a key regulator of the integrated stress response and cytosolic proteotoxicity. ROCK1 controls the interplay of HRI with HSP90 and limits the recruitment of HRI and HSP90 to unique p62/SQSTM1 complexes that also contain critical kinases like mTORC1 and TBK1, and proteins involved in RNA metabolism, oxidative damage, and proteostasis like TDP-43. Thus, ROCK1 helps B cells cope with intense pathogen-driven destruction by coordinating the activity of key controllers of B cell differentiation and stress responses. These ROCK1-dependent mechanisms may be widely employed by cells to handle severe environmental stresses, and these findings may be relevant for immune-mediated and age-related neurodegenerative disorders.
Authors
Juan Rivera-Correa, Sanjay Gupta, Edd Ricker, Danny Flores-Castro, Daniel Jenkins, Stephen Vulcano, Swati P. Phalke, Tania Pannellini, Matthew M. Miele, Zhuoning Li, Nahuel Zamponi, Young-Bum Kim, Yurii Chinenov, Eugenia Giannopoulou, Leandro Cerchietti, Alessandra B. Pernis
Abstract
BACKGROUND. We aimed to characterize factors associated with the under-studied complication of cognitive decline in aging people with long-duration type 1 diabetes (T1D). METHODS. Joslin “Medalists” (n = 222; T1D ≥ 50 years) underwent cognitive testing. Medalists (n = 52) and age-matched non-diabetic controls (n = 20) underwent neuro- and retinal imaging. Brain pathology (n = 26) was examined. Relationships amongst clinical, cognitive and neuroimaging parameters were evaluated. RESULTS. Compared to controls, Medalists had worse psychomotor function and recall, which associated with female gender, lower visual acuity, reduced physical activity, longer diabetes duration and higher inflammatory cytokines. On neuroimaging, compared to controls, Medalists had significantly lower total and regional brain volumes, equivalent to 9 years of accelerated aging, but small vessel disease markers did not differ. Reduced brain volumes associated with female sex, reduced psychomotor function, worse visual acuity, longer diabetes duration and higher inflammation, but not with glycemic control. Worse cognitive function, lower brain volumes, and diabetic retinopathy correlated with thinning of the outer retinal nuclear layer. Worse baseline visual acuity associated with declining psychomotor function in longitudinal analysis. Brain volume mediated the association between visual acuity and psychomotor function by 57%. Brain pathologies showed decreased volumes, but predominantly mild vascular or Alzheimer’s-related pathology. CONCLUSION. This first comprehensive study of cognitive function, neuroimaging and pathology in aging T1D individuals demonstrated that cognitive decline was related to parenchymal rather than neurovascular abnormalities, unlike type 2 diabetes, suggestive of accelerated aging in T1D. Improving visual acuity could perhaps be an important preventive measure against cognitive decline in people with T1D.
Authors
Hetal S. Shah, Matthew N. DeSalvo, Anastasia Haidar, Surya Vishva Teja Jangolla, Marc Gregory Yu, Rebecca S. Roque, Amanda Hayes, John Gauthier, Nolan Ziemniak, Elizabeth Viebranz, I-Hsien Wu, Kyoungmin Park, Ward Fickweiler, Tanvi J. Chokshi, Tashrif Billah, Lipeng Ning, Atif Adam, Jennifer K. Sun, Lloyd Paul Aiello, Yogesh Rathi, Mel B. Feany, George L. King
Abstract
CD8+ T cells are critical for immune protection against severe COVID-19 during acute infection with SARS-CoV-2. However, the induction of antiviral CD8+ T cell responses varies substantially among infected people, and a better understanding of the mechanisms that underlie such immune heterogeneity is required for pandemic preparedness and risk stratification. In this study, we analyzed SARS-CoV-2-specific CD4+ and CD8+ T cell responses in relation to age, clinical status, and inflammation among patients infected primarily during the initial wave of the pandemic in France or Japan. We found that age-related contraction of the naive lymphocyte pool and systemic inflammation were associated with suboptimal SARS-CoV-2-specific CD4+ and, even more evidently, CD8+ T cell immunity in patients with acute COVID-19. No such differences were observed for humoral immune responses targeting the spike protein of SARS-CoV-2. We also found that the proinflammatory cytokine IL-18, concentrations of which were significantly elevated among patients with severe disease, suppressed the de novo induction and memory recall of antigen-specific CD8+ T cells, including those directed against SARS-CoV-2. These results potentially explain the vulnerability of older adults to infections that elicit a profound inflammatory response, exemplified by acute COVID-19.
Authors
Gaëlle Autaa, Laura Papagno, Takuto Nogimori, Andrea Boizard-Moracchini, Daniil Korenkov, Maeva Roy, Koichiro Suzuki, Yuji Masuta, Eoghann White, Sian Llewellyn-Lacey, Yasuo Yoshioka, Francesco Nicoli, David A. Price, Julie Dechanet-Merville, Takuya Yamamoto, Isabelle Pellegrin, Victor Appay
Abstract
In the mammalian cochlea, sensory hair cells are crucial for the transduction of acoustic stimuli into electrical signals, which are then relayed to the central auditory pathway via spiral ganglion neuron (SGN) afferent dendrites. The SGN output is directly modulated by inhibitory cholinergic axodendritic synapses from the efferent fibers originating in the superior olivary complex. When the adult cochlea is subjected to noxious stimuli or aging, the efferent system undergoes major rewiring, such that it reestablishes direct axosomatic contacts with the inner hair cells (IHCs), which occur only transiently during prehearing stages of development. The trigger, origin, and degree of efferent plasticity in the cochlea remains largely unknown. Using functional and morphological approaches, we demonstrate that efferent plasticity in the adult cochlea occurs as a direct consequence of mechanoelectrical transducer current dysfunction. We also show that, different from prehearing stages of development, the lateral olivocochlear — but not the medial olivocochlear — efferent fibers are those that form the axosomatic synapses with the IHCs. The study also demonstrates that in vivo restoration of IHC function using AAV-Myo7a rescue reestablishes the synaptic profile of adult IHCs and improves hearing, highlighting the potential of using gene-replacement therapy for progressive hearing loss.
Authors
Andrew P. O’Connor, Ana E. Amariutei, Alice Zanella, Sarah A. Hool, Adam J. Carlton, Fanbo Kong, Mauricio Saenz-Roldan, Jing-Yi Jeng, Marie-José Lecomte, Stuart L. Johnson, Saaid Safieddine, Walter Marcotti
Abstract
Radiotherapy (RT) remains a primary treatment modality for glioblastoma (GBM), but it induces cellular senescence and is strongly implicated in GBM progression and RT-related injury. Recently, eliminating senescent cells has emerged as a promising strategy for treating cancer and for mitigating radiation-induced brain injury (RBI). Here, we investigated the impact of all-trans retinoic acid (RA) on radiation-induced senescence. The findings of this study revealed that RA effectively eliminated astrocytes, which are particularly prone to senescence after radiation, and that the removal of senescence-associated secretory phenotype factor–producing astrocytes inhibited GBM cell proliferation in vitro. Moreover, RA-mediated clearance of senescent cells improved survival in GBM-bearing mice and alleviated radiation-induced cognitive impairment. Through RNA sequencing, we found that the AKT/mTOR/PPARγ/Plin4 signaling pathway is involved in RA-mediated clearance of senescent cells. In summary, these results suggest that RA could be a potential senolytic drug for preventing GBM progression and improving RBI.
Authors
Min Fu, Yiling Zhang, Bi Peng, Na Luo, Yuanyuan Zhang, Wenjun Zhu, Feng Yang, Ziqi Chen, Qiang Zhang, Qianxia Li, Xin Chen, Yuanhui Liu, Guoxian Long, Guangyuan Hu, Xiaohong Peng
Abstract
Given the potential fundamental function of osteal macrophages in bone pathophysiology, we study here their precise function in experimental osteoporosis. Gene profiling of osteal macrophages from ovariectomized mice demonstrated the upregulation of genes that were involved in oxidative stress, cell senescence and apoptotic process. A scRNA-seq analysis revealed that osteal macrophages were heterogenously clustered into 6 subsets that expressed proliferative, inflammatory, anti-inflammatory and efferocytosis gene signatures. Importantly, postmenopausal mice exhibited a 20-fold increase in subset-3 that showed a typical gene signature of cell senescence and inflammation. These findings suggest that the decreased production of estrogen due to postmenopause altered the osteal macrophages subsets, resulting in a shift toward cell senescence and inflammatory conditions in the bone microenvironment. Furthermore, adoptive macrophage transfer onto calvarial bone was performed and mice that received oxidative-stressed macrophages exhibited greater osteolytic lesions than control macrophages, suggesting the role of these cells in development of inflammaging in bone microenvironment. Consistently, depletion of senescent cells and oxidative-stressed macrophages subset alleviated the excessive bone loss in postmenopausal mice. Our data provided a new insight into the pathogenesis of osteoporosis and sheds light on a new therapeutic approach for the treatment/prevention of postmenopausal osteoporosis.
Authors
Yoshio Nishida, M. Alaa Terkawi, Gen Matsumae, Shunichi Yokota, Taiki Tokuhiro, Yuki Ogawa, Hotaka Ishizu, Junki Shiota, Tsutomu Endo, Hend Alhasan, Taku Ebata, Keita Kitahara, Tomohiro Shimizu, Daisuke Takahashi, Masahiko Takahata, Ken Kadoya, Norimasa Iwasaki
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