Synergistic and feedback signaling mechanisms in the regulation of inflammation in respiratory infections

Wenzhuo Y. Wang, Jae Hyang Lim, Jian Dong Li

Research output: Contribution to journalReview articlepeer-review

26 Scopus citations


Pneumonia, the most typical and frequent lower respiratory tract infection (LRTI), is a leading cause of health problems in the United States. Bacteria represent the most prevailing cause of pneumonia in both children and adults. Although pneumonia with a single bacterial infection is common, a significant portion of patients with pneumonia is polymicrobial. This infection is often complexed with other physiological factors such as cytokines and growth factors. Nontypeable Haemophilus influenzae (NTHi) is the most frequently recovered Gram-negative bacterial pathogen in the respiratory system and induces strong inflammatory responses. NTHi also synergizes with other respiratory pathogens, such as Streptococcus pneumoniae and respiratory viruses and pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-γ±). It is noteworthy that NTHi not only synergizes with growth factors such as transforming growth factor-beta (TGF-γ2), but also utilizes growth factor receptors such as TGF-γ2 receptor and epidermal growth factor receptor (EGFR), to enhance inflammatory responses. Although appropriate inflammation is a protective response against invading pathogens, an uncontrolled inflammatory response is often detrimental to the host. Thus, inflammation must be tightly regulated. The human immune system has evolved strategies for controlling overactive inflammatory response. One such important mechanism is via regulation of negative feedback regulators for inflammation. CYLD, a multifunctional deubiquitinase, was originally reported as a tumor suppressor, but was recently identified as a negative regulator for nuclear factor-kappa B (NF-κB) signaling. It is induced by NTHi and TNF-γ± via a NF-κB-dependent mechanism, thereby serving as an inducible negative feedback regulator for tightly controlling inflammation in NTHi infection.

Original languageEnglish
Pages (from-to)131-135
Number of pages5
JournalCellular and Molecular Immunology
Issue number2
StatePublished - Mar 2012

Bibliographical note

Funding Information:
This work was supported by grants from National Institute of Health DC005843, DC005843-S1, DC004562 and AI073374 (to J-DL) and AHA 10SDG2630077 (to JHL).


  • CYLD
  • NF-kB
  • negative regulation
  • nontypeable Haemophilus influenzae
  • synergistic regulation


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