The human microglial HMC3 cell line: where do we stand? A systematic literature review

Abstract

Microglia, unique myeloid cells residing in the brain parenchyma, represent the first line of immune defense within the central nervous system. In addition to their immune functions, microglial cells play an important role in other cerebral processes, including the regulation of synaptic architecture and neurogenesis. Chronic microglial activation is regarded as detrimental, and it is considered a pathogenic mechanism common to several neurological disorders. Microglial activation and function have been extensively studied in rodent experimental models, whereas the characterization of human cells has been limited due to the restricted availability of primary sources of human microglia. To overcome this problem, human immortalized microglial cell lines have been developed. The human microglial clone 3 cell line, HMC3, was established in 1995, through SV40-dependent immortalization of human embryonic microglial cells. It has been recently authenticated by the American Type Culture Collection (ATCC®) and distributed under the name of HMC3 (ATCC®CRL-3304). The HMC3 cells have been used in six research studies, two of which also indicated by ATCC® as reference articles. However, a more accurate literature revision suggests that clone 3 was initially distributed under the name of CHME3. In this regard, several studies have been published, thus contributing to a more extensive characterization of this cell line. Remarkably, the same cell line has been used in different laboratories with other denominations, i.e., CHME-5 cells and C13-NJ cells. In view of the fact that “being now authenticated by ATCC®” may imply a wider distribution of the cells, we aimed at reviewing data obtained with the human microglia cell line clone 3, making the readers aware of this complicated nomenclature. In addition, we also included original data, generated in our laboratory with the HMC3 (ATCC®CRL-3304) cells, providing information on the current state of the culture together with supplementary details on the culturing procedures to obtain and maintain viable cells.

Oxyresveratrol Inhibits IL-1β-Induced Inflammation via Suppressing AKT and ERK1/2 Activation in Human Microglia, HMC3

“…These results clearly indicate that OXY can alleviate the production of important inflammatory mediators in IL-1β-induced HMC3 cells. Although HMC3 cells have been reported to have no nitric oxide (NO) generation since there is no expression of inducible nitric oxide synthase (iNOS) [ 16 ], we still tested for the production of NO and the expression of iNOS in response to IL-1β stimulation and asked whether OXY has inhibitory effects on iNOS expression and NO production. As expected, data clearly showed that there was no iNOS expression and very low levels of NO in HMC3 induced with IL-1β, and OXY at all concentrations did not generate any difference in the level of iNOS and NO ( Supplementary Materials Figure S1A–G ).…”

“…The modulation of ERK1/2 phosphorylation is crucial for relaying the signaling for the production and secretion of different nociceptive factors (cytokines such as TNF-α and IL-1β or enzymes COX-2, iNOS, and nNOS), which are related to an increase in the neuropathic pain sensations [ 32 , 33 , 34 ]. However, it has been reported that HMC3 cells cannot express iNOS nor produce nitric oxide (NO), even when stimulated with several different inflammatory stimuli [ 16 ]. Our current data confirmed the previous report since we could not detect iNOS in this cells in comparison to the high level in the lysate of LPS-induced RAW 264.7 cells.…”

Neuroprotective effect from Salvia hispanica peptide fractions on pro‐inflammatory modulation of HMC3 microglial cells

“…In the present study, the 100 µM TBHP radical was used to induce oxidative stress on HMC3 cells. According to Rawat and Spector (2017), macrophages are resistant to damage by H 2 O 2 given their capacity to respond to the lesion, since the microglia have a basal production of H 2 O 2 ; reason why the use of TBHP radical has a greater stability than H 2 O 2 in the generation of injury and ROS induction (Dello Russo et al, 2018). After incubation for 2 hr with TBHP, HMC3 cells increased ROS levels by 2 times.…”

β-Hydroxybutyrate Oxidation Promotes the Accumulation of Immunometabolites in Activated Microglia Cells

“…To study the metabolism of BHB in microglia, the cell lines BV2 (mouse) and HMC3 (human) were chosen as microglia cell models. These cells conveniently recapitulate the most important aspects of the biology of the microglia and have been previously used in a number of studies [ 42 , 43 , 44 ]. The concentration of BHB rises in physiological conditions characterised by limited glucose availability [ 45 ].…”

“…BV2 cells are immortalized microglia cells that recapitulate a large proportion of the phenotypic traits of primary and in vivo microglia. They have been widely used to study microglia biology [ 42 , 43 , 44 ], and observations have successfully been validated in primary and in vivo microglia studies [ 104 , 105 , 106 ]. However, some limitations in the use of these cell lines have been reported.…”