Biology subjects

Bellamkonda, R. V.

Publications and source records attributed to Bellamkonda, R. V..

4 recordsLinked to original sources

bioRxiv2021

DIY caging apparatus to facilitate chronic and continuous stimulation or recording in an awake rodent

Chronic stimulation of and recording from the brain and brain diseases can require expensive apparatus and tedious cycles of inducing rodents with anesthesia. To resolve this, we have designed and fabricated a low-cost ([~]$75 vs. $450) DIY rodent caging apparatus consisting of commercially available and 3D-printed components. This apparatus is customizable and can be used to rapidly prototype devices with large rodent sample sizes. Importantly, it enables continuous and chronic stimulation of and recording from the brains of awake and freely moving rodents. It also opens the possibilities of trying complex paradigms of treatment (continuous, intermittent, variable, and chronic). We have successfully used this caging apparatus for chronic intratumoral hypothermia treatment and are currently using it while advancing electrotactic therapies.

bioengineering↗

bioRxiv2021

Cytostatic hypothermia and its impact on glioblastoma and survival

Novel therapeutic approaches are needed for patients with glioblastoma (GBM) who otherwise have limited options. Here we studied and deployed non-freezing cytostatic hypothermia to stunt GBM growth. This contrasts with ablative, cryogenic hypothermia: a double-edged sword against tumors infiltrating otherwise healthy tissue. We investigated three grades of hypothermia in vitro and identified a cytostatic window of 20-25{degrees}C. For some glioma lines, 18 h/d of cytostatic hypothermia was sufficient to halt division in vitro. Cytostatic hypothermia induced cell cycle arrest, reduced metabolite production and consumption, and reduced inflammatory cytokine synthesis. Next, we fabricated an experimental device to test local cytostatic hypothermia in vivo in two rodent models of GBM: utilizing the rat F98 and the human U-87 MG lines. Hypothermia more than doubled the median survival of F98 bearing rats from 3.9 weeks to 9.7 weeks and two rats survived through 12 weeks. All U-87 MG bearing rats that successfully received cytostatic hypothermia survived their study period. Thus, this approach lengthened survival without chemical interventions. Unlike targeted therapeutics that are successful in preclinical models but fail in clinical trials, cytostatic hypothermia affects multiple cellular processes simultaneously. This, alongside reduced cellular division, suggests that opportunities for tumor evolution are reduced and the likelihood of translation to larger species may be more likely. In addition, based on our work, designs, and the literature, engineering a patient-centric device is tangible. Taken together, cytostatic hypothermia could be a novel approach to cancer therapy and eventually serve a valuable role to patients with GBM. One Sentence SummaryHypothermia influences multiple cellular pathways, can be a safe and effective approach to halt glioblastoma growth, and holds translational promise.

bioengineering↗

bioRxiv2020

Enriching neural stem cell and pro-healing glial phenotypes with electrical stimulation after traumatic brain injury in male rats

Traumatic Brain Injury (TBI) by an external physical impact results in compromised brain function via undesired neuronal death. Following the injury, resident and peripheral immune cells, astrocytes, and neural stem cells (NSCs) cooperatively contribute to the recovery of the neuronal function after TBI. However, excessive pro-inflammatory responses of immune cells, and the disappearance of endogenous NSCs at the injury site during the acute phase of TBI, can exacerbate TBI progression leading to incomplete healing. Therefore, positive outcomes may depend on early interventions to control the injury-associated cellular milieu in the early phase of injury. Here, we explore electrical stimulation (ES) of the injury site in a rodent model (male Sprague-Dawley rats) to investigate its overall effect on the constituent brain cell phenotype and composition during the acute phase of TBI. Our data showed that a brief ES for 1h on day 2 of TBI promoted pro-healing phenotypes of microglia as assessed by CD206 expression and increased the population of NSCs and Nestin+ astrocytes at 7 days post-TBI. Also, ES effectively increased the number of viable neurons when compared to the unstimulated control group. Given the salience of microglia and neural stem cells for healing after TBI, our results strongly support the potential benefit of the therapeutic use of ES during the acute phase of TBI to regulate neuroinflammation and to enhance neuroregeneration. Significance StatementTraumatic brain injury (TBI) occurs when a head injury leads to a disruption of normal function in the brain and is a major cause of death and disability, worldwide. The authors used electrical stimulation during the acute phase of TBI, which promoted pro-healing phenotypes of microglia and increased the number of neural stem cells and Nestin+ astrocytes, thereby enhancing neuronal viability. These findings support further study of electrical stimulation to regulate neuroinflammation and to enhance neuroregeneration after TBI. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=157 SRC="FIGDIR/small/372979v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@1bdc466org.highwire.dtl.DTLVardef@1a912c4org.highwire.dtl.DTLVardef@10f269dorg.highwire.dtl.DTLVardef@1b02487_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFIGURE 1.C_FLOATNO C_FIG

bioengineering↗

bioRxiv2020

Evaluation of M2-like macrophage enrichment after diffuse traumatic brain injury through transient interleukin-4 expression from engineered mesenchymal stromal cells

Appropriately modulating inflammation after traumatic brain injury (TBI) may prevent disabilities for the millions of those inflicted annually. In TBI, cellular mediators of inflammation, including macrophages and microglia, possess a range of phenotypes relevant for an immunomodulatory therapeutic approach. It is thought that early phenotypic modulation of these cells will have a cascading healing effect. In fact, an anti-inflammatory, "M2-like" macrophage phenotype after TBI has been associated with neurogenesis, axonal regeneration, and improved white matter integrity. There already exists clinical trials seeking an M2-like bias through mesenchymal stem/stromal cells (MSCs). However, MSCs do not endogenously synthesize key signals that induce robust M2-like phenotypes such as Interleukin-4 (IL-4). To enrich M2-like macrophages in a clinically relevant manner, we augmented MSCs to transiently express IL-4 via synthetic IL-4 mRNA. We observed that these IL-4 expressing MSCs indeed induce a robust M2-like macrophage phenotype and promote anti-inflammatory gene expression in a modified TBI model of closed head injury. However, here we demonstrate that acute enrichment of M2-like macrophages did not translate to improved functional or histological outcomes. This suggests that an acute enrichment of M2-like macrophages cannot solely orchestrate the neurogenesis, axonal regeneration, and improved WMI after diffuse TBI. To further understand whether dysfunctional pathways underlie the lack of therapeutic effect, we report transcriptomic analysis of injured and treated brains. Through this, we discovered that inflammation persists in spite of acute enrichment of M2-like macrophages in the brain. Last, we comment on our modified TBI model, behavioral studies, and propose that IL-4 expressing MSCs may also have relevance in other cavitary diseases or in improving biomaterial integration into tissues.

neuroscience↗